PTF-17, PTF’s in general and Coastal River Division 21 Ops:
Updated – 5/13/18
First, a little background: Why PTF’s? The Green Water Navy.
Despite what several Keyboard Kommando’s have stated online, the PTF’s did not operate on the rivers of Vietnam nor were they part of the “Brown Water Navy”. Read on….
During their deployment to Vietnam the PTF’s operated as the primary naval weapons of MACV-SOG’s* OPLAN 34A. The boats were nominally leased to the RVN Navy and crewed “officially” by South Vietnamese Sea Commando sailors when operating north of the 17th parallel – the “demilitarized zone”. Very fast, heavily armed and long-range, the boats and crews were highly effective for their small numbers in the mission objectives of using both conventional naval operations and unconventional warfare (U/W) to return the war back to the communist thugs in Hanoi.
*Military Assistance Command Vietnam-Studies and Observations Group.
This included operations in the Tonkin Gulf stopping the infiltration of personnel, weapons and ammunition being sent south by the “Democratic Republic of Vietnam”. These PTF missions were run from Da Nang and supported by the US Navy Mobile Support Team One an element of MACV-SOG’s Naval Advisory Detachment located there. These now-declassified missions were code-named “PLOWMAN” and “PARBOIL”. They also supported cross-beach “CADO”, “FOOTBOY” and other U/W operations.
Above: An early Nasty class PTF with two 40 mm guns. The 40 mm gun mounted on the bow was removed at Subic Bay and replaced with an 81mm mortar/.50 cal BMG prior to deployment to Vietnam. Official US Navy photograph, location and date unknown, likely in the Philippines, circa 1963, early 64.
During combat operations in Vietnam the PTF’s were also armed with additional “weapons of opportunity”. These included 57 mm recoilless rifles and launchers for Soviet 122 mm rockets captured from the VC/NVA. A 106 mm recoilless rifle was also tried but the backblast and firing shock was a bit too much so that idea was scrapped.
Many of the communists’ coastal cargo vessels, armed Junks and “fishing” boats carrying supplies to the Viet Cong and NVA were shot up or sunk on these “LOKI” Junk-capture missions north of the DMZ. This included some of their P-4, P-6, Swatow and Shanghai gun/torpedo boats that tried to stop the PTF’s. Those were also shot up, sunk or outrun by the PTF’s on these missions. Along with the related “Market Time” patrols further south, stopping this seaborne infiltration was successful enough that the communists had to shift most of their infiltration to the “Ho Chi Minh trail(s)” through Laos and Cambodia. These operations off the coast of North Vietnam also caused the communists to divert tens of thousands of troops from the assault on the South to defend their own coastal areas against these missions.
However, the PTF’s primary missions were offensive in nature. Those were to insert and extract the U.S. Navy SEAL-trained Sea Commando’s of the Republic of Vietnam’s Navy into North Vietnam to run attacks against NVN naval and coastal installations supporting the subversion of the South. That included gunnery and mortar attacks against the communists’ shore based radar sites, military installations, bridges on Route 1, artillery positions, port facilities, transhipment sites and targets of opportunity. PTF operations were also instrumental in conducting prisoner captures and PsyOps against the communist north. More on that later on….
Offensive PTF operations against Viet Cong and North Vietnamese Army strongholds in coastal South Vietnam were also the targets of DEWEY RIFLE and BIFROST/DODGE MARK missions crewed by US Navy personnel along with Vietnamese crew members. See References (7), (8) and (18) primarily. Note that the PTF’s of the “Green Water Navy” were not used in riverine warfare like the smaller PBR’s, PCF’s, ATC’s and similar small craft of the Brown Water Navy down south in the Mekong Delta.
The PTF was not designed or suited for operations in confined canals, rivers, inland waters and the like – they were too big and too deep draft for those environments and their long range and speed would not be advantageous there. Also, the big diesels could not operate at low speeds for very long – more on that later. They carried a big offensive punch but their best defense when needed was open water speed. Photo Below: Curt Froyen
To put some of this document into post-war context, I was a Plank Owner in Coastal River Division 21, having received active duty Orders to the unit in the winter of 1972-1973. By then the boats had redeployed to CONUS and were still in post-deployment overhaul while making preparations for supporting NATO operations in northern Europe. This was certainly NOT Vietnam but the boat crews and supporting staff were almost all recently back from Vietnam deployments – except me, “the new guy”. As a “Boot Ensign” I was initially assigned to CRD-21 Staff as Weapons Officer and Electronic Materiel Officer. I subsequently also served as Executive Officer of PTF-18 and then “fleeted-up” as Officer in Charge of PTF-17 (seen above), a distinct honor, challenge and responsibility for a young Ensign. And fortunate to have landed THE best job in the Navy!! Our great crew trained me and kept me out of trouble – in the finest Navy tradition.
After enlisting in the Navy in May, 1971 as a Seaman Recruit, I graduated from Boot Camp at Great Lakes, completed Class “A” School (Communications Technician) in Pensacola, Officer Candidate School at Newport RI and then to the Naval Training Center, back at Great Lakes. (I had requested “small combatants” on my assignments Dream Sheet). After completing my active duty time with CRD-21 in 8/75, I served on CRD-21 staff as a drilling reservist for an additional year in the billet of Assistant Ops Officer while maintaining my former collateral duties as Weapons Officer and Electronic Materiel Officer.
The PTF: The first 80 foot, wood-hulled Nasty Class PTF boats were built in Norway, based upon their Tjeld Class Motor Torpedo Boats. The Norwegians learned from WWII PT boat experiences and built upon them – unfortunately we did not. We gave up on this type of vessel after WWII when most surviving Pacific boats were burned on the beach at Samar in the Philippines. They Were Expendable….The next time it would be a “push button war”.
Then the North Vietnamese communists invaded South Vietnam just as the North Korean communists invaded South Korea in 1950.
With no enemy targets worthy of (or approved for) a torpedo, the US Navy outfitted them as heavily armed gunboats, not unlike the WWII PT boats used to take THAT fight back to Japan, especially in the New Guinea campaign. However the hybrid type-name “Fast Patrol Torpedo Boat”, “PTF” surfaced. So we bought 14 boats from Norway (PTF’s 3-16), dubbed as the Nasty Class PTF.
We then built another 6 PTF’s (PTF-17, 18, 19, 20, 21 and 22) as virtual copies under license to fulfill our needs in Vietnam. Those 6 were built by John Trumpy and Sons in Annapolis MD in 1967-68 and are sometimes called “Trumpy’s” or sometimes “PTF-17 Class” or sometimes “Nasty’s”, depending upon the document. PTF-17 was launched on 11/17/67 after a 7 month construction effort. She was delivered to the US Navy on 7/1/68 after fitting out.
CRD 21’s Boats: Some Background: The boats of Coastal River Division 21, PTF’s 17, 18 and 19 operated in Vietnam for several years.
There are several photos elsewhere on the web of Da Nang (as well as Cam Ranh Bay) harbor and the PTF base piers during the late 1960’s – early 1970’s. The boats pictured are clearly Trumpy’s as indicated by the distinctive rectangular slot radar antennas. (PTF’s 3-16 had a prominent curved radar antenna described elsewhere on this website). The Da Nang photos show boats that could have been any of PTF’s 17-22 but the photo’s don’t show the specific hull numbers. PTF’s operating in North Vietnamese waters were unmarked. There are also numerous photos of PTF’s being repaired and overhauled back at Subic, including one described as PTF-17 getting some damaged planking repaired. Again, many Trumpy’s but no obvious individual hull numbers are visible. The declassified record is pretty thin when it comes to combat ops of individual boats by hull number; that sort of detail did not make it in the overall operations summaries. Hopefully more will be revealed over time, especially by the actual participants.
Hanoi’s February 1968 Tet offensive in South Vietnam was a tactical disaster for them when the people of South Vietnam didn’t “rise up” against the government as hoped. Despite their tactical surprise the Viet Cong and many North Vietnamese Army elements involved in the South were essentially destroyed. But they achieved their strategic objective of further turning “useful fools” (V. Lenin) in the American public against further combat to defend the South. That bought the NVA time to rebuild their forces in the South. So among other actions, in November 1968 the President ordered the cessation of PTF PLOWMAN Ops against enemy forces north of the 17th parallel (however PTF Ops continued in the South). In 1969, COMUSMACV recommended to the Joint Chiefs of Staff that PTF’s 17-22 be pulled back and held in reserve at Subic Bay, believing that the existing 7 Nasty’s at DaNang could handle scaled – back taskings.
During that time frame some OPLAN 34A maritime ops were being cut back due to transfer of responsibilities to the RVN forces but also as an economy of forces savings. The JCS did not act upon the recommendation regarding the 17-22 boats. It appears that some of them were deployed along with the remaining PTF’s to make up for losses, mostly groundings in poorly-charted North Vietnamese waters. (Reference 7, MACV-SOG Maritime Ops Summary, 1970). The 4 Osprey aluminum hulled PTF’s (23, 24, 25 and 26) were previously withdrawn from DaNang in 1968 after only 6 months of operations – their aluminum hulls suffering severe fatigue cracking. Those 4 were replaced by at least 4 of the Trumpy boats (Ref. 34). But things heated back up in early 1971 with several successful PTF raids north of the DMZ which shot up or sank numerous North Vietnamese gunboats, luggers and supply boats.
With the disestablishment of MACV-SOG in 1972 and the ending of the RVN leasing arrangement, the PTF’s were redeployed back to the US and assigned to the Coastal River Squadrons and Divisions, formerly called Boat Support Units prior to June 1971. I cannot find a solid reference to when the boats actually moved back to the US or how they were transported. That was likely done as cargo aboard an LSD or similar ship. It is known that PTF-26 was transported back as deck cargo aboard the USS Tuscaloosa, LST 1187.
CRD-21’s 3 boats were sent to the Naval Amphibious Base (NAB) at Little Creek VA and at least PTF-17 did some exercise work (Exotic Dancer series) in the Atlantic in 1971-1972 before they went to CRD21 at Great Lakes in October 1972. (and no, they were not used to “train recruits” at the Great Lakes boot camp as a couple of Keyboard Kommando’s have proclaimed online.) PTF’s 20, 21 and 22 were assigned to CRS 2 at NAB Coronado for Pacific Fleet ops.
Below are some photos of PTF-17 operating in the Atlantic circa early 1972. This was possibly in conjunction with the Exotic Dancer fleet training exercises off the Virginia Capes or training workups out of Guantanamo Bay Cuba. When the PTF’s were not performing training missions or supporting SEAL teams, they were often utilized in Fleet Training Exercises to simulate Soviet OSA or Komar missile patrol boats in running long range approaches against other exercise units.
The following 3 photos courtesy of GMGC(SW) Rob Summerhill USN who was a Gunners Mate aboard the USS Joseph Hewes DE 1078 at the time. See the Comments section below. Thanks Chief!
This one shot through a telephoto lens at a distance.
PTF-17 approaching the USS Hewes.
PTF-17 coming alongside the port quarter of the USS Hewes for a post-exercise debrief at-sea with the crew. I have found no information indicating that PTF-18 or 19 were also involved in these exercises. They were both PTF-17 “Classmates” and all 3 boats were at NAB Little Creek at the time before deploying to Great Lakes.
I cannot find any definitive official references to the dispositions of the remaining Nasty boats (hulls 3-16 minus the operational or combat groundings) but most if not all ended up at Little Creek VA. The 3 CRD21 boats made the transit from NAB Little Creek to Great Lakes via the Hudson River, the Erie Canal system and Lakes Erie, Huron and Michigan. Can any of you Coastal River Squadron Two guys provide any detail here?
Above: A nicely detailed mahogany 1/48 scale model of PTF-17 along with some representative ammo. This model was built from “scratch” by a shipyard worker at Peterson Boat Builders in Sturgeon Bay Wisconsin in late 1974. He built it from scrap mahogany utilizing detailed measurements he made of the actual boat while it was in winter overhaul at the boat yard. The hull is a single, solid piece. He came aboard with calipers, rulers and a clipboard, documenting all measurements. He even used some of the Marine 123 green and red anti-fouling bottom paint to get the colors exactly right. Glass case cover removed.
Representative ammunition in the case: 40 mm “Bofors” automatic cannon high explosives round, 20 mm high explosives round, .50 caliber M2 BMG, 7.62 mm M-60 machine gun belted rounds. We also carried M-16’s, M-79 grenade launchers, M-870 shotguns, .45 automatics and a .38 cal revolver. Oh, and the 81 mm mortar on the bow. See the “PTF Firepower” category in this blog for further weapons details.
Another view. The boat builders at Peterson did outstanding work; their specialty was wooden boats. They also built many mine sweepers, patrol boats, tug boats, sub chasers and landing craft for WWII. They were building wood minesweepers for the Republic of Korea and aluminum hulled 65 foot US Navy patrol boats while we were there in overhaul. True craftsmen. It was amazing to watch them steam-bend long mahogany hull planks with compound curves that then fit precisely into the hull of our PTF’s.
Surviving PTF‘s: (to my knowledge as of April 2018)
PTF-3 (the first Nasty) is at 29 degrees 3.435 N x 81 degrees 17.29′ W (Deland FL)
PTF-10 (reportedly) was at 36 degrees 45.30N x 76 degrees 18.15W in a November 2016 Google Earth photo (Chesapeake Yachts VA)
PTF-17 (the first Trumpy) is now located at 42 degrees 52.653’ N x 78 degrees 52.801’W (Buffalo NY)
PTF-19 is located at 39 degrees 16.447 N x 76 degrees 10.081 W (at Worton Creek Marina near Worton MD)
PTF-25 Wreck is located at 35 degrees 1.90 N x 76 degrees 27.85W (in the MCAS Cherry Point NC gunnery range BT-11)
PTF-26 often moored at 38 Degrees 8.98 N x 121 degrees 40.99 W (near Rio Vista CA. See earlier Google Earth photos)
PTF-23 (the first Osprey) has been heavily modified structurally, including small 12V71 Detroit diesels, modified deck house and the addition of a small crane. It is back east as the Research Vessel “Osprey” Completely unrecognizeable as a PTF from the deck up – but it’s afloat.
In May 2018 it appeared for sale in Boats and Harbors for $225K, presently located in Port Canaveral FL.
PTF-26 (the last Osprey) is operational in the San Francisco Bay area, based in Rio Vista CA with the Liberty Maritime Museum. . PTF-26 has been modified with Detroit diesels replacing the Napier Deltic’s and some superstructure modifications including added windows in the CIC area and the inclusion of a small deck house aft. It is otherwise complete, in good shape and underway – it even has a 40 mm “Bofors” gun back aft.
The rest of the boats are gone, lost to accidental or combat groundings, missile and gunnery tests or the scrappers. “Excessed” by the Navy in the late 1970’s, seven “east coast” wooden boats ended up rotting on the sand for 15 years at Great Bridge VA. A Google Earth photo taken in April 2002 showed 7 PTF’s on the beach, in a photo taken a year later, they were gone (36 43.570’N 76 15.048’W). One apparently went to the UK; then most off to a local marina (Chesapeake Yachts) for scrapping.
Incidentally, the disposition and provenance of the boats once they left US Navy service is very fuzzy due mainly to poor identification markings on the specific, surviving boats. Once the hull numbers had been sanded off the bridge and overpainted there was little else to definitively identify any particular boat. The defining engraved stainless steel identification plates bolted to the aft bridge bulkhead (at least on the 17, 18 and 19 boats) were lost to souvenir thefts. Some equipment and fittings had apparently been marked with an associated hull number but yard work at Subic Bay and DaNang during the war found many parts being swapped during repairs, temporary cannibalizations and overhauls. “Get her back in the fight!”
More on that later. I can positively identify PTF’s 17, 18 and 19 due to unique repairs but the identity of the rest of the boats is buried in history someplace. The website ptfnasty.com has lots of information, speculation, observations and photos of the the boats while on the East Coast, after the US Navy disposed of them.
Below is a shot of PTF-18 up on step. Authors Photo:
PTF’s 23-26 were different boats entirely – the “Osprey” class built by Sewart Seacraft in Berwick, Louisiana in 1968. They were 95 foot aluminum hulled boats but with the same Napier Deltic engines and weapons systems. They were reportedly too big and heavy (at 105 tons) to really get up “on step” and cruised more as a “semi-displacement” type hull would despite the same engines. They were therefore slower – by 5 knots – than the planning-hull Nasty’s according to Reference (9); Jane’s Fighting Ships and Reference (17); PT Boats at War .
There are some references stating the Osprey’s were originally built to be powered by a gas turbine engine – hence the huge air intake structure behind the pilot house. (It’s also possible that only one Osprey was to be turbine powered, however they all have that large air intake structure. More research needed here.) That would have been a great system for a boat that size although at the expense of fuel economy. With all that aluminum they also had a much bigger radar return too, not good for stealthy Ops or when up against radar-controlled guns. Reference (7) states all 4 Osprey’s were briefly in Da Nang in 1968. However, they were withdrawn back to the US within 6 months because their aluminum hulls developed severe fatigue cracks from the pounding in the open sea. Can any of you Osprey – MST/BSU vets expound upon any of this?
Above a nice shot of PTF-26 off the Golden Gate, San Francisco during Fleet Week, October 2010. Taken from the S.S. Jerimiah O’Brien Liberty ship. Note that the owners (Liberty Maritime Museum) have applied a camouflage pattern based on the WWII Elco Boat. PTF-17 had a unique camouflage adaptation during the brief time that scheme was experimented with back at Great Lakes. (Interestingly, the owners of PTF-3 seemed to have duplicated the PTF-17 design and colors during the PTF-3 restoration back in Florida). There are no known published photos of the PTF’s with pattern-camouflage during the Vietnam war – they were painted Marine Formula 123 Lustreless Green. But the 26 boat sure looks great out there – and OPERATING!! The last of the PTF’s. Photo by Jason Atkin. Thanks to Liberty Maritime for setting me straight on the PTF-26 camo design.
Welcome Aboard: This article will describe life aboard PTF-17 and Coastal River Division 21. I’ll note the very minor differences between the Norwegian and Trumpy PTF’s, and point to references about their Vietnam combat Ops to the extent that some of this information is now being declassified. I was still in Navy schools / training when that effort was ongoing.
CRD21 certainly wasn’t Vietnam, the Canadians were very friendly, but there we were, sometimes freezing, roaring around the Great Lakes of all places. That was our new, post-Vietnam mission; training to support future NATO ops in northern Europe. As a Division of the east coast Coastal River Squadron 2, the Great Lakes were a good place for us to train for cold weather environments.
Take a tour of PTF-17 as it was assigned to Coastal River Division 21, an element of Coastal River Squadron 2 based in Little Creek VA. See photo’s of main systems, weapons, communications, engineering etc. Included are photo’s of PTF 18 and 19 as well as the Patrol Gunboats Asheville, Crockett and Marathon, PG’s 84, 88 and 89.
Command and Control:: All tactical combat units require the ability to move, shoot and communicate. So let’s start with Comms since command and control is essential to the mission. There is almost no information on the Web describing the communications systems on PTF’s so I will attempt to fill in some of that void. (Since I was also a Ham Radio operator and an electronics engineer, this aspect of the boats was also of particular interest to me.)
“All members of a MTB crew must be qualified in standing a radio watch. Each man must have an operating understanding of the radio equipment, know the Morse Code, understand the effective call sign, and Recognition and Emergency Identification System.” From the WWII “Motor Torpedo Boats Tactical Orders and Doctrine” manual. 1942
PTF-17 had HF, VHF and UHF transceivers to cover most comms needs. (Reference 64.) Our JANAP plain language call sign was Culpepper Sierra 17, quite a mouth full, so we normally used simply “Tango One-Seven”, particularly between the boats. My “personal” call sign was Tango One Seven Actual in keeping with the protocol of the day. The CRD-21 callsign was Richard November, AKA “Two-One”.
The photo below shows the radio room of PTF-17. On the right, top is the HF transceiver ARC-94. Its control head is behind the white stanchion just above the CW key. Below the ARC-94 is the ARC-27 UHF transceiver – its control head is up on the bridge. On the operating table we see the SB-315 CW key and to the left of that is the VRC-46/RT-524 VHF transceiver. It is locally tuned and has a C-1138 remote control on the bridge. Above the VRC-46 are the three AM-215/U audio amplifiers. These can select any radio output, amplify it and route it to any speaker or handset. There are also various junction boxes and patch panels in view. A compact, efficient space. This view is looking outboard, forward is to the right.
High Frequency Radio: We had an AN/ARC-94, based upon the Collins 618T aircraft transceiver operating from 2-30 MHz which was mounted in an overworked shock mount in the radio room. The radio room was approximately under the port side 20 mm gun mount. This radio provided SSB, CW and AM capability with 400 watts PEP output on SSB but we only used SSB. (plus an occasional AM radio check with some surprised CB’er on 27.065 MC). It drove a Collins 490T automatic antenna matching unit which was mounted on the after bulkhead of the chart room and it was connected to the port side 28 foot fiberglass whip antenna.
Some photo’s of these boats while in Vietnam (and also while on post-launch sea trials on Chesapeake Bay) show the two HF whips mounted forward of the bridge, braced with support struts to the bridge structure. Some time later, on some boats, they were moved further aft to the positions seen in my photo’s. Also, our fold-down main radio / Nancy Beacon mast seems to have been a later modification. Some Vietnam photo’s don’t show this mast. A photo of a PTF hulk in Great Bridge Virginia also shows the HF whip mounted forward with the support struts.
The HF radio drove an H-169/U handset remote unit on the bridge and its normal aircraft control panel for frequency and mode selection was mounted in the radio room. The radio was powered by the boats’ 28 VDC batteries as well as a 28V-115V 3 phase 400 cps rotary “inverter” which was located in the weapons locker in the passageway across from the head. The radio could be operated locally in the radio room via an RS-38 Mic plugged directly into the transceiver.
The NAVSHIPS Technical Manual (see Reference (15)) for the PTF-17 Class also shows the CW-only AN/GRC-109 as standard, installed equipment. Also interesting, the Manual for PTF’s 9-16 (the last 8 Norwegian boats) shows a nice photo of a Collins TCS AM and CW HF Radio set in the Radio Room and notes this radio was installed equipment. The photo also shows the TCS Loading Coil, required for use with a 28 foot whip on the lower frequencies. It appears that the TCS’s were aboard the 9-16 boats while in Vietnam as the primary HF radio at least at some point. Interesting, considering that the same Collins TCS was the primary radio system used in the WWII PT boats.
At some point prior to 1966, the ARC-94 SSB/CW radio was being used on some, if not all of the Nasty Class boats. It was noted that maintaining the ARC-94 was problematic due to the severe mechanical shocks they encountered while underway. Repair work was difficult on these complex aircraft radios due to repair parts logistics and the lack of specific training by NAD personnel on these particular sets. A recommendation was made to either improve the ARC-94 shock mounts or install (re-install?) the WWII vintage TCS sets as a replacement! (Reference (33). I cannot determine if this was ever done on all, or any particular Nasty boats.
Curiously, the GRC-109 transmitters were not directly connected to an antenna on CRD-21’s boats as we received them, even though the PTF’s had a second 28 foot whip on the starboard side of the bridge. All Nasty and Trumpy Class PTF’s (and the Osprey’s) had two HF antennas and it is highly likely the starboard antenna was dedicated for the GRC-109’s. There was no provision for any starboard antenna matching and in fact, I recall that the receivers and AC power supplies were missing when we received the boats. The transmitters were bolted to the radio room forward bulkhead, about eye level and there was an SB-315A/U CW key located on the operating desktop next to the VRC-46.
Since the ’109 was not complete or operative on any of the boats, I initiated a request to Division and Squadron for a BOATALT (boat alteration) to remove them. As the Staff Electronics Materiel Officer for CRD21 (collateral duty) I was responsible for making sure all the shore and afloat equipment was working and supported properly. It was approved and they were excessed; one less mystery problem to deal with but we never received a modern replacement for them. (If someone can get aboard PTF-17 at the Servicemen’s Museum in Buffalo, please take a picture of the forward bulkhead and note the position of the GRC-109 mounting holes – I’d appreciate it!). More details on the AN/GRC-109 sets here: AN/GRC-109
The CW key for the ARC-94 or the GRC-109 could be “patched in” via the two gray junction boxes mounted above the key. The ARC-94 radio was capable of operating CW via the Mode switch on the control panel. Our Radiomen in the crews were all CW qualified in those days, unlike today. Most of our comms were tactical, boat-to-boat FM voice. Long range comms back to base were another matter; that was normally SSB voice. The built-in CW key mounted on the GRC-109 transmitter would have been barely usable with the transmitter being mounted vertically on a bulkhead, at eye- level. The transmitter has provision for an external key which would have been much more practical in that installation. There is a NAVSHIPS drawing that details each communications system, including the GRC-109 but they are in the National Archives; I have not seen them. More research needed.
During the war, the GRC-109 was relied upon extensively for comms back to Base during raids in their operating areas. Ref (7) indicates they used the following freqs for CW with the GRC-109 (incorrectly identified as the CIA’s nearly-identical “RS-1” in the document): Transmit/Receive: 4069.3/8217, 4258/4632, 6220/3493 KC as primary, secondary and tertiary circuits respectively. Split T/R operation would have been routine and its likely the Ops officers/OinC’s had authority to pick the best freqs for day/night operations, the “hot work” happening mainly at night. Reference (33) states that there were severe logistics issues in obtaining additional crystals for these sets despite many special request follow-ups. A trip to “Radio Row” in New York could have quickly produced barrels of FT-243 crystals being bought back from the surplus dealers of the day. I remember seeing 55 gallon drums of FT-243’s for 25 cents apiece in those days. Finding suitable frequencies would have been pretty simple….JAN, Texas Crystals, Peterson, ICM and a host of others were still selling FT-243’s to any frequency you wanted for a few dollars. Huh?
The use of those “split Frequency” assignments ruled out the ARC-94 as a possible CW radio on the PTF’s, at least in split frequency operation. It is incapable of operating on separate transmit and receive frequencies. I believe this is good evidence that the GRC-109 (and by implication the TCS radio on the older boats) was the primary long-range radio set used on these missions. However, during the 8 war years of PTF operations with different classes of boats delivered and/or modified at different times, almost any configuration was possible.
A 28 foot whip would be resonant around 8.3 MC. However with its feedline and ground line to the bronze ground plate along the keel, in a wood hull, the resonant frequency would be somewhat lower. The 4 and 6 MC transmit freqs would have seen a capacitive load without any matching devices; the receivers would have worked fine. They probably just tuned up and let the ’109 grunt out CW. I’ll have to try that setup with mine to see how they handle it. While at aboard PTF-17 I did run my Heathkit SB-102 SSB Transceiver into the starboard whip without a tuner on 40 meters Ham frequencies and it worked great, I’m sure the GRC-109′s did the job, mine always does.
Here’s a shot of the Heathkit SB-102 SSB transceiver aboard PTF-17 during a Ham Radio Field Day back then, probably 1975. The starboard HF whip antenna is visible outside the bridge window.
Back to the ARC-94′s. We used the HF radios on occasion, particularly when we were underway around the Great Lakes on various training and recruiting port visits. We had several HF freqs available but mostly used 6970 KC USB which covered the ranges of interest. They had no squelch so they were a bit annoying being turned up to overcome the formidable engine noise when at-speed. One day the USS Marathon ran into a problem while transiting the St Lawrence Seaway, inbound to Great Lakes from Guam. They called us on 6970 KC’s, we had good comms and got them the assistance they needed. This was before Cell Phones don’tchya know!
Reference (7) states that HF SSB radios, UHF radios, IFF gear, galley equipment etc (being “U.S. attributable”) and the forward 40 mm gun mount were removed from the Norwegian Nasty boats (Hulls 3-16 inclusive) at Subic prior to commencing Ops in 1964. Again, Reference (7) has noted later on the availablity of SSB voice (for the ARC-94, misidentified in Ref (7) as the “GRC-94″) and assigned SSB freq’s in combat aboard the PTF’s but it appears it was not used for voice comms. (Reference (32)). (Conflicting references, more research is needed here but the unclassified record is pretty vague and it contains several typo’s and other mistakes.) It is possible that the ARC-94 SSB radios were only briefly in the Nasty hulls but they were installed in the Trumpy’s from the very beginning. However, I have learned that the ARC-94 was routinely used on offline – encrypted CW circuits (possibly from the Nasty Class) to send hourly SITREPS while on PLOWMAN missions, at least in the 1969-70 timeframe. (Reference 32)
During covert intel ops, psyops and full-on raids, HF AM or SSB would have been too easy to intercept; no crypto capability, using a complex and therefore a possibly less-than-reliable radio system. The intercept problem would have been serious since the boats primarily operated with local crews who spoke the same language so it would have been easy to perform COMMINT against them. Encrypted CW would have been more secure. The operating areas were around 200-250 miles over sea water from Base, so a TCS set or a 10 watt GRC-109 sending coded CW would do the job pretty reliably. A 400 Watt ARC-94 would have been an even easier shot when necessary. I wonder what the tropical static noise sounded like with all that lightning around.
Incidentally, our HF comms aboard were very quiet. Although each engine had 18 cylinders and 36 pistons, they were diesels – no ignition noise! Fluorescent lighting was quiet and mostly brushless motors in the aux gear. It made for a very quiet RF environment.
VHF: On VHF we relied upon the trusty AN/VRC-46/RT-524 FM radio also mounted in the Radio Room. It covered 30-75 MC with output of around 35 watts into the AS-1729/VRC whip antenna. We used the VRC-46 for 90% of our Comms as it was reliable and had SQUELCH! The whip was originally mounted on the forward starboard side of the bridge and the radio used a C-1138 remote control box with H-189/U handset on the bridge. A great radio system that could handle the pounding that often caused the other radios to fail.
Our primary freq was 39.00 MC. Apparently that freq was also common to US Army armor units at Ft Knox, infantry units at Bragg and other Army units in the country because we often talked with them when “skip” propagation was in. Pretty reliable, pretty often. We talked with guys in tanks, APC’s, CP’s and even some PRC-25′s being humped around. We also worked an Army helo once – indicated by rotor blade modulation of his signal. We’d ask “how’s the chow”, they wanted to know “how’s the fishing”…. When we got back in, we could look up their daily callsign and find out who/where they were. You could always tell when you were talking to a VRC-46 – the cooling blower and HV switching supply for the output tube had a distinct, loud background whine. The Russian REK (Radioelectronic Kombat) guys would have had a field day with us…
We also carried a PRC-25 (or was it a 77?). Our SEAL team used it when going ashore on training exercises in their IBS, Inflatable Boat Small. Great radio, always worked. I remember when the message came in directing all PRC-25 owners to install the battery vent device in the side of the battery boxes. Apparently the new BA-4386 magnesium batteries out gassed hydrogen and some cigar-smoking RTO probably blew himself up with one. I believe that message was actually the first directive establishing The Great Nanny-State we presently find ourselves in.
The VRC-46 system worked well but as stated earlier, it was not quite enough to make it from our gunnery training areas back to base. I experimented by installing another AS-1729 whip on the top of our foldable mast, getting it somewhat higher and more in the clear. It made about a 15% improvement in range so I submitted a BOATALT request up the chain and got it approved for the PTF’s.
UHF: We had an AN/ARC-27 aircraft radio, a very heavy 1950′s beast that we used to talk with aircraft and occasionally each other. The antenna was the Navy standard AS-390 “spider” up on the fold-over mast. H-169/U handset and a small Channel Select panel up on the bridge. The ARC-27 in the Radio Room would wear out the overworked shock mounts on a regular basis and then fail. We had a deal with the Naval Air Station at Glenview Illinois to provide us repair support as that was still a common radio in Mil aircraft as was the ARC-94. They’d fix our gear, we would take them for rides.
As noted above, much US-supplied equipment was removed from the Nasty boats before they were leased to the RVN navy for non-attribution purposes. However shortly after they arrived in Vietnam, ARC-27 UHF radios were installed on the PTF’s at DaNang in order to coordinate air cover with RVN Air Force A1H Skyraiders.
We also talked with NAS Glenview’s P-3 Orions of VP-60 as they “searched for subs” in the deeper sections of the Lakes, on their way out to the Atlantic to track the real Russian subs operating off our coast. The P-3’s used to like sneaking up on us from astern, blasting by us at low altitude when we were underway. They left a big wake in the water from those 4 big turboprops. The lookouts spotted them long before, so we were ready. Hitting them with the morse letter “G” from the signal lights, the standard exercise surrogate for Gunfire; they buzzed off, probably not knowing morse code or surface warfare training trivia. Ha Ha, we got ya – BS! We got you…
We did a fair amount of search and rescue training with the US Coast Guard units at Chicago. They flew H-3 Helo’s and we did many underway transfers of simulated litter patients, usually simulated by a case of beer wrapped inside a kapok life jacket lashed to a stokes stretcher. We quickly learned the “helo static electricity grounding stick trick”. Grabbing a stokes stretcher hung by a steel cable from a helo while standing on the aluminum soft-patch over the engine room provided quite a static electricity jolt! Build a whack-stick from a piece of pipe, ground wire to the deck plate and whack the stretcher BEFORE you touched it – helo rotors could build up a lotta volts… Authors Photo Below:
Fun Fact: The UHF radio came in handy one day while we were firing 81 mm mortar illumination flares and the .50 Cal in a daytime training exercise. A lookout reported incoming aircraft (CEASE FIRE!) and soon a TWA 727 jet buzzed us about 2000 feet above the water in a hard left bank. The firing area was in the south-center part of the lake and was apparently under a VOR path into O’Hare airport. The pilot apparently thought we were in distress by seeing all the flares, he was still too far away to see the .50 Cal TRACERS! So I figured I would call him on the UHF Guard freq of 243.0 MC. Even civilian aircraft guard that freq, right?
Wrong, but the control tower at Naval Air Station Glenview did and replied, asking why Navy PT Boat-17 was calling unknown TWA 727 in the Lake Michigan Controlled Firing Area on the aircraft emergency frequency. (A reasonable question.) I explained the situation to him, he got on the O’Hare tower freq and called off the 727. Probably a rare occasion for an airliner pilot to buzz a PT boat. He was probably an Air Force Reserve C-130 zoomie on drill weekends. Commence firing.
We also had a PRC-41 UHF manpack. Used it to talk with the Helo’s occasionally but rarely carried it. I think we got it from salvage along with the batteries and charger. Comshaw….
Here’s another shot of underway Air Ops with the Coast Guard. Standard Air Ops procedure was to pick a course (assuming you had clear navigation) to put the relative wind 30 degrees off the port bow at about 20 knots. This allowed the helo to fly directly into the relative wind and permit the pilot to see what’s going on. (Helo pilots usually sit in the right-hand seat unlike in fixed wing aircraft). This also allowed the winch operator to get a good view of the situation. They look like they are “crabbing” into the wind but they are not. authors Photo
Marine Band VHF: We carried a Raytheon RAY-50 on the bridge for talking with the many civilian boats in the area. Particularly in the FIRING AREA. These people were clueless, having never read a Notice To Mariners requiring them to stay clear of this charted location. (Come to think of it, that TWA pilot probably didn’t read the Notice to Airmen that we also routinely sent out. But I’m glad he looked anyway).
We would also use the RAY-50 to talk with the Locks operator on the Chicago River when we needed to clear the locks, occasional drawbridge operators and particularly iron ore and grain boats plying the Great Lakes. These guys would travel to/from Chicago right through the firing area and would rarely answer a call on Channel 16 or 13 (bridge-to-bridge). We’d pull up alongside and hit the horn to chase them away and if anyone even appeared on the bridge wing, they’d just shrug and keep going. Time is money ya know and I gotta get back to the Poker game! Sheesh!
Other Electronics: The PTF’s had a gyro compass, a Mark 27 Mod O as I recall. Pretty reliable but it would “tumble” if we pounded down off some big waves. (back to the magnetic compass). A gyro repeater was on the bridge and it was also sync’d to the main radar and radar remote on the bridge. Good gear. We carried a Canadian Marconi LN-66 radar as well. Very reliable and could spot a DIW PT boat about 4 miles out, much further if it was as speed because the rooster tail in the wake showed up more than the boat did. We could see a PG gunboat at about10 miles. We also had a fathometer (couldn’t detect fish) and a pit sword for speed indication read out by cool Nixie Tubes.
Fun Fact: In 1974 the line of zero degrees of magnetic variation ran down the west side of Lake Michigan. Also, when the guns were locked down in their cruise positions, the wood hull of the boat did not influence the magnetic compass. Therefore True north and Magnetic north were in the same direction; the gyro and magnetic compass read the same. No need to use the old Navigators memory trick: True Virgins Make Dull Company At Weddings. If you were ever a Navy navigator, you know what that means.
Fun Fact: It’s easy to tell a Norwegian – built PTF from a Trumpy boat at a distance. The Trumpy LN-66 radar antenna was a straight, rectangular “slotted waveguide” antenna. The Norwegian Nasty’s had a Decca radar with a prominently curved reflector-horn antenna *. Also, any PTF photo showing a 40 mm gun mounted on the bow is a Norwegian-built boat – the Trumpy’s always had the 81mm Mortar/Browning M2 .50 Cal machine gun combo on the bow. After arrival in theater the Norwegian boats also had the 81/50 weapon on the bow as a replacement for their 40 mm guns. Positive visual ID features.
(* There is a photo identified in Reference (17) as PTF-13 (Norwegian -built) with some experimental guns installed. It sports the straight LN-66 Radar antenna versus the curved antenna of the Decca radars, the only exception I have found. PTF-13 was apparently kept stateside as a training and a Tech Evaluation boat during the war. The LN-66 radar was apparently being evaluated for future incorporation in the new-construction boats starting with PTF-17.)
ADF: When we got the boats back from Vietnam they had a curious automatic radio direction finder (ADF) system aboard. Very handy off the coast during radar EMCON, when outside NVA artillery range or in making lengthy transits. (we didn’t carry any celestial navigation gear or pubs, although we were qualified).
The rotating loopstick antenna was inside about a 6 inch square, 2 inch thick block mounted on a mast between the bridge and the forward centerline ammo ready service locker. The electronics and readout was in the chart room and it was strange indeed. It was a US Mil aircraft ADF system of some sort as indicated by the aircraft-type control panel and azimuth display dial. But they were mounted in a metal box, about 1 foot cube, obviously made by an unemployed automotive sheet metal worker at Subic and spray painted (kinda) in haze gray. What a kludge. The metal looked like it was cut with a cold chisel and nothing was square. Also, it didn’t work on any of the boats. Another BOATALT request up the chain and they are gone (but a good ADF system would have been very useful and we never got a replacement system).
The boats also had a NANCY infrared signaling system. It consisted of an incandescent light bulb inside an infrared glass dome filter mounted up on the mast. It is the black-looking hemisphere on the mast in the USCG Helo photo, above. We had an IR viewer (SAR-7 I recall) so we could see it, the naked eye could not. The light was controlled by a box to the helmsman’s left on the bridge bulkhead, either continuous “on”, pulsating or keyable in morse code with a key depending upon where the function switch was set..
Fun Fact: We would do frequent “cat and mouse” ops, under radar EMCON conditions with the other boats, trying to infiltrate some remote, long coastal area undetected by the other boat(s) that were patrolling it. One night, we were the patrol, PTF-18 was going to try to insert the SEALS in. Earlier that day, I had sauntered over to PTF-18 at the pier, turned their NANCY beacon “ON” in the pulsating mode and then removed the selector switch knob and repositioned it, pointing towards the “OFF” position. We could see them coming miles away – they never figured it out. Some more info on our SEAL Det and training here:
CRD-21 SEAL Detachment
Visual Signaling: In addition to the NANCY system, we had two 8″ signal lights mounted behind the bridge, port and starboard. They were the mechanical shutter type for sending morse code. They had different colored filters, including infrared and could be used as clear searchlights as well. Pretty effective, simple gear – it worked. The light(s) could be removed and our M-60 machine guns mounted in the pintle’s in their place. We also carried a limited Flag Bag, consisting of an Ensign, Jack, Golf (if you were the Guide in formation ops), a 21 Division pennant, Oscar (man overboard) and a Bravo flag for fueling, and gunnery ops.
We also carried an early GEN 1 starlight scope with mounts for an M-16 rifle.
Fun Fact: One warm, moonless Saturday night at Zero-Dark-Thirty, we were idling along the beach, darken ship (looking for VC or Spetsnaz infiltrators). Intel had us off Lake Forest Illinois, the home of a fancy liberal arts college – there were probably plenty of enemy sympathizers in the area. Movement! The starlight scope detected much hanky-panky happening among the college students in the bushes along the beach. Until we hit them with the search lights and then hit the engines. Pandemonium! Now, more enemy sympathizers…
Here is an ancient copy of the Underway Check Off list we posted – stuff you needed to do prior to takeoff.
The Front Office: Above is a shot of the Bridge. Above the dashboard is the pelorus for taking bearings. Underneath, left to right: Windshield wiper switch, Gyro-compass repeater, VRC-46 speaker, pit log (Knot-Ometer), C-1138 remote control for the VRC-46. On the panel, left to right: Helm (hydraulic steering), magnetic compass, engine RPM indicators, rudder-angle indicator, throttle/transmission levers, engine warning lights, fire detection warning lights, navigation lights switchboard, cease fire horn buttons for 4 main weapons, and LN-66 radar repeater. Along the vertical bulkhead are 2 weather tight H-169/U handset holders (HF and UHF usually patched to them) and a small door hiding the ARC-27 UHF radio control box. The sound powered phones were usually worn by the OOD but sometimes the helmsman depending upon the evolution. Off to the right out of the photo are the depth indicator, General Quarters and Collision Alarm switches. Behind the bridge crew are 2 weatherproof speakers for the radios (loud!). The Ray 50 VHF Marine Band radio was mounted behind the watertight door down to CIC but the door was kept open while underway. Authors Photo
Hull / Overall Design:
As stated earlier, the hull of PTF-17, like the Norwegian boats was made of wood, 7 different kinds I was told. Oak keel, mahogany planking, ash frames, elm stringers, douglas fir plywood decks etc. The Trumpy-built boats were built in the US but the keels and stem assemblies were apparently imported from Norway as part of the licensing deal. The boats were 80 feet long with a 24 foot beam, 6 feet wider (but the same length) than the WWII Elco boats. This permitted the installation of more weapons, equipment and crew, and especially to contain ten 600 gallon diesel fuel tanks amidships. This was a “planning hull” and above about 25 knots or so, the entire sides from the chine to the rub rail and the entire transom were dry. Above 30 knots, the Bull Nose would drop and you were cooking.
The bad news was that broad beam made operation in rough water pretty tough as it would not slice down through the waves like a narrower hull would. We came down so hard sometimes the shock would trip circuit breakers on the main switchboard OFF as the breaker handles kept going down but the boat didn’t. It was also tough on legs, knees and ankles at times. It wasn’t the North Atlantic but Lake Michigan had some very rough weather with big waves but since the fetch was relatively short, the wave period was fast (they were close together). You didn’t go up and down on swells, you tended to crash through them. As a consequence, of the several hundred photo’s I took at CRD21, I have very few of PTF’s at-speed; you were trying too hard just to hang on and holding a camera steady (or keeping it dry) wasn’t going to happen.
The Great Lakes supposedly has the highest number of shipwrecks per square mile than any other body of water on earth – I believe it. Lake Michigan alone has over 3000 shipwrecks of substantial size plus innumerable smaller pleasure craft. The 730 foot Edmund Fitzgerald ore freighter encountered such weather in Lake Superior and disappeared and sank without a trace or even a distress call.
Another Great Lakes hazard to navigation were “deadheads”. These were telephone poles or other large caliber wooden pilings that a zillion docks, quay walls and dolphin mooring posts were made of. During the winter ice-over, the ice would grab the poles and when the lake rose (due to a low-pressure weather system moving in), it took the piling up a few inches with it. After awhile they worked themselves out of the bottom and the ice dragged them off as it shifted around. Since they were waterlogged at the bottom and bouyant at the top, they floated vertically, often just awash with the surface. You had to keep a sharp lookout for them and they made night ops particularly scary since you could not see them on radar until it was too late. Hit one of these and you had a big hole below the water line – or no more screws or rudders. Another example that “Eternal Vigilance is the Price of Safety”. Fortunately, none of us ever hit one but there were a few close-calls.
The hulls were “plywood” just like the WWII boats. This is not the 4×8 sheets you get at Home Depot (although the deck and pilot house were made of laminated plywood). The hull was made of 2 layers of narrow mahogany planks, about 6″ wide each. The inner planks were about 45 degrees to the keel, the outer planks roughly parallel to the keel. The outer planks were about 1/2 thick, the inner planks somewhat thicker. There was a waterproof, resilient adhesive coating (not fiberglass as some have reported) between the plank layers and they were screwed to the frames, stringers and fish-plates with stainless steel wood screws. The WWII PT boats had over 400,000 wood screws holding them together. Our boats must have had at least that many. Very strong.
I think the Frames were on 12 or 14″ centers. Light, flexible, strong, hard to build, easy to repair. PTF-17 had several combat-era bullet/shrapnel holes in the hull – the repairs can be seen inside covered with odd wood block patches glued and screwed to the inner planks at various places among the more regular fishplates. The outside holes were probably filled with Bondo or something. The hull planking was removed, replaced and repaired many times during overhaul at Subic during the war years.
Here’s a May, 1967 photo of PTF-17 under construction at John Trumpy and Sons. Naval Photographic Center, Wash DC. From ptfnasty.com website.
I managed to bang into the corner of the steel pier while pulling out of a berth on the Huron River, backing into where it empties into the current of the St Claire River. I scraped about a 24″ long gouge in the outer planking, punching a 6″ hole through the inner planking about 12 inches above the water line. It cracked a hull frame about midway down the port side of the engine room. Oh Crap! Tied back up. EN2 Carl R. and ETN2 Bill T. screwed a huge piece of a 3/4″ marine plywood damage-control patch over the hole and we were off again. Oh, except they painted it like a big white Band Aid. I deserved it.. See below. Point is, easy to screw up but also easy to repair. Our “ships carpenter”, QMC “Barney”, made an expert repair of the frame and both layers of planking when we returned back to base. If you can get aboard PTF-17 in Buffalo, look in the engine room, port side, outboard of the underwater exhaust pipe and check out my handi-work!
“Nice Pants!” A civilian visitor aboard during our port call. “Why is there a band-aid on your boat?”
One April day we were departing Peterson Boat Builders in Sturgeon Bay Wisconsin after a winter overhaul. It was PTF-18, I was XO at the time. The lake had cleared of ice a few weeks ago (so we thought) and as we zig-zagged (see below) down the canal, alternating engines to keep the speed down. We felt a bump.
Investigating, we discovered we had hit an awash ice floe which knocked about a 6 inch hole in the starboard side below the waterline, just aft of the water tight bulkhead in the lazarette; it was starting to flood. We could have gotten out to the main lake area and hit the gas – getting up on step would have put the hole above the water and the lazarette would have drained itself.
In an abundance of caution, and not wishing to hit any more ice at-speed, we did some basic damage control (in waist-deep ICE COLD WATER), energized the bilge pump and headed back to Sturgeon Bay. Of course, the gas-powered P-250 de-watering pump test-ran fine at the pier, now it wouldn’t start in the freezing cold wind out on the lake. Radioing ahead, they met us back at the pier with a crane holding a huge concrete clump anchor. As we pulled in, we put some dunnage on the port bow and they lowered the clump. Bow goes down, stern goes up, hole now out of water. A day later, back underway again.
By the way, if you are “restoring” a surplus PTF and it has that repaired damage in the lazarette just below the waterline, you have PTF-18! Similarly, if your PTF has a 8″ patch in the transom directly above and outboard the starboard exhaust pipe, you have PTF-19. The Naval Station LCVP ran into PTF-19 while it was moored. Positive ID here….
Apparently PTF’s-19 and 18 “traded some paint” during an ammunition transfer; shortly before they departed for Little Creek upon decommissioning of CRD-21 in 1976. I remember hearing about it with Chief Barney doing some repairs on the forward “rub rail” on the 19 boat. Again, easy to repair.
We carried about 15-20 crew members at a time when the Reservists were aboard for training; the boats being designed for 4 officers and 20 crew depending upon the mission and weapons requirements. There were 4 racks in the Wardroom and 14 in the crews quarters, accounting for those on watch – “hot bunking” it’s called.
The hull was fairly immune to gross trim changes when loaded with fuel and ammo – it rode about the same when when lightly loaded. It weighed 65 tons dry, about 80 tons when fully loaded, good design accounting for this trim stability with the center of gravity not changing much as we burned fuel. With 6000 gallons of fuel aboard we could go 860 miles at 38 knots, 960 miles at 35 knots or 1050 miles at 20 knots. By way of comparison, a standard highway fuel tanker truck carries 6000 gallons for those volumetrically-challenged folks.
Draft at the screws at 75 tons was 6’10″ and at the bottom of the keel was 3’9″ so you could nose into a beach or mud bank if the bottom dropped off quickly. These were not “PBR” River boats of PCF Swift boats – PTF’s were used in the South China Sea and Tonkin Gulf and the engines were pretty unhappy if you had to idle along in shallow water for very long. With both engines at dead idle (750 RPM) you were doing about 12 knots, much to the angst of the Coast Guard while in “no wake zones”. The rudders were pretty ineffective at low speeds so you would steer zig-zag with the engines (idle or in neutral) to maintain steerage way at low speeds. With those big 4 foot screws, set wide apart and powered by monster engines, they were otherwise pretty maneuverable at low speed. Going slow in a straight line required “pulsing” both engines, something the engines, transmissions, clutches and engineers didn’t like. Carbon and all that…
The boats would easily make 45 knots when lightly loaded in fresh water, especially if it was really cold outside with cold, (dense) air being sucked in by the big turbo superchargers screaming away. They would be a bit faster in sea water (higher density, more prop-bite, more mass for the prop to accelerate). We rarely went above 40 knots as there was no real need and engines were very expensive – they required overhaul when reaching 20 cumulative hours above 2100 RPM. Overhaul was at still Subic Bay in the PI. More on that later…
FUN FACT: You can visually estimate the speed of one of these boats. In calm water at a typical loading the keel cuts the water just under the 81mm mortar mount when the boat is at 40 knots and under the centerline 81mm ready service locker at 45 knots; more forward when slower. The photo on the front page was taken at around 20 knots, not yet up on step.
Camouflage: While in Vietnam, and as we received them, they were painted in Marine Formula 123 lustreless green. A good general purpose camouflage. Not Haze Gray because they routinely operated close to the beach when doing Hot Work. Haze Gray is for TARGETS and other big, fat, slow, gray floating hazards to navigation like destroyers etc…One commenter at another PTF web site stated that the Naval Training Center ordered us to paint the boats in “that hideous camouflage pattern”. Not so! – it was our idea. (The Commander NTC actually wanted us to paint them Haze Gray since that’s what The Real Navy looked like. To him.)
Over the winter overhaul period of 1974-75, I had suggested to Commodore Johnston that we try different Camo schemes to evaluate how effective they were. He enthusiastically agreed so I drew up some sample ideas based upon some WWII patterns. He got the OK from Squadron so off we went. We tried the wavy pattern on PTF-17 placing Haze Gray and flat black waves on top of the Marine 123 on all vertical surfaces. The 19 Boat got Leopard Spots consisting of Haze Gray amoebas with flat black centers, also on top of Marine 123. The 18 Boat got Razzle Dazzle triangle splinters of Haze Gray with flat black interiors, also on Marine 123. This was NOT to try to look inconspicuous while at-sea. In all cases, the decks and other horizontal surfaces were kept 123 green. Remember, this is the Green Water Navy, not brown water or blue water….
Above: A very blurry port-quarter shot of PTF-17 in early 1975 showing the overall camouflage pattern. Also note the second AS-1729 VHF radio antenna has been installed on top of the main mast to increase range. Unfortunately at this time I cannot locate any of the photo’s I took of PTF’s 18 or 19 with their unique patterns.
Note the portside main engine exhaust and cooling water spewing from the transom exhaust; the main engine exhaust bubbling up from the underwater port. The transom exhaust is effective while the boat is stopped or moving slowly. The much larger underwater port handles the main exhaust at-speed. Note the steam cloud from the port diesel 15 KW electric generator on this cold morning.
To evaluate the camouflage, we did some visibility test by running close-aboard the beach and viewed from seaward, in different lighting conditions and at differing ranges.
Depending upon the background, the 17 and 19 boats were pretty well hidden, the 18 Boat not so much. In all cases we were running at slow speed – nothing you could do would hide the big white Rooster Tail in the wake at speed. We would imagine that while hugging the shoreline the camo would be somewhat effective when viewed by a Mach 1 Fast Mover heading for the Officers Club. Especially if the decks were also camouflaged. Just another “lump”. When painted solid 123 green they were more obvious against a typical shoreline, looking like an odd solid dark shape – out of place.. And what are those muzzle FLASHES !?
The 18 Boat was different with the Razzle Dazzle triangles. With triangle bases offset from structural vertical features, it was a bit difficult to ascertain the “target angle” of the boat you were looking at. This is the bearing the PT boat presented to you, from their perspective. It was meant to confuse gunners or fire control viewers about exactly which way you were going. Intended to be confusing for a few critical seconds, it worked pretty well for us and apparently very well in the WWII boats (including large Capital ships) as witnessed by many photos of them sporting this design. However, in the end that was too hard to apply and maintain so Razzle Dazzle was dropped in favor of simpler designs during WWII. We eventually went back to solid 123 green at the end of the experiments and when the paint just wore out. Great leaders, willing to experiment without fear of offending or upsetting someone. It fit in with our mission – and attitude.
Here’s a shot of the PTF’s on the marine railway after being hoisted by the new synchrolift. They were pulled in the winter for overhaul but primarily to prevent damage from the thick ice that formed in the harbor. When frequent storms blew in, the ice smashed itself into big chunks and those chunks smashed anything they contacted. That’s my 1971 Ford Bronco – still driving it but now it sports a desert camo paint job – seen elsewhere on this site. Authors Photo Below:
Engineering Main Control: The below photo shows the engineers station which was actually in the fuel tank room. He monitored all engineering systems while looking aft through the double-pane window into the engine room. He had the main engine run-stop switches and a duplicate set of throttle/transmission controls although the boat was always controlled from the bridge. The port and starboard panels contain the 18 engine cylinder temperature gauges (rectangular gauges) for each engine, the RPM indicators and the other gauges to measure sea-suction water temperature, coolant temperature, lube oil temp and pressure, fuel oil pressure, Vee drive oil pressure and temperature, turbo-supercharger temperature and pressure, generator lube oil temperature and pressure and a few other critical things I am forgetting. The big gauges read main-start compressed air flask pressure. That big white cylinder seen through the window is the port main lube-oil tank. It was loud in Main Control and unbearably loud (more like a FEELING) in the engine room, even with ear plugs covered by mickey-mouse ears.
Note that the Main Control layout in the Norwegian boats (PTF’s 3-16) is different than the Trumpy’s. A good internal identifier. If you’ve got a Trumpy boat, the main control looks like this (or if your radar antenna is the straight LN-66 design).
Engines and Vee Drives:
British Napier Deltic T18-37K diesel marine/locomotive engines. Eighteen opposed-piston cylinders arranged in a compact triangle (Delta) , 3 crankshafts, 36 pistons, turbo supercharged, lightweight, aluminum 3100 horsepower (each), 5384 cubic inch displacement screamers. Two of them. Basically converts #2 diesel into noise, spray and adrenalin …More to follow.
With its origins back in WWII, the Brits outdid themselves with the design of this engine. Not for the faint-at-heart! Incredible engineering to produce so much power in such a small volume. There are many sites on the Web describing this engine in detail – check them out, especially the animations. Suffice to say, there is a lot of hardware flying around inside this powerhouse.
Below is a photo of a 3100 horsepower Napier Deltic engine sitting on a shipping stand waiting to be installed in PTF-19. It had just arrived via USAF C-141 jet transport from Subic Bay, PI. The main engine overhaul shop during the war was in Subic and the Navy elected to keep it there to support us. That fact and the complexity of these engines were eventually what caused the PTF program to be killed off during the Jimmy Carter years – too expensive, no neutrons, not enough push-buttons. “They Were Expendable” rears its head again. But I digress…..
Like all diesel engines, they are thermodynamically most happy and efficient when run at a constant speed as in diesel electric locomotives and ships or as prime movers for generators. These guys idled at about 750-800 RPM. As you accelerated through about 1100 RPM they hit a mechanical resonance which was very ugly and probably damaging – get through there quickly. Above about 1300 RPM they were very smooth. I’ll never forget the sound of them driving that screaming turbo supercharger. When you shut them down (cut fuel) they sounded briefly like a giant dumpster half full of bowling balls being shaken by King Kong. Then DEAD, HOT quiet. As your hearing tried to recover.
The New York City Fire Department had a water pumper truck “The Super Pumper” in service from 1965-1982. It used a Napier Deltic T18-37K to drive a water pump that could deliver 8800 GPM at 350 PSI. Or 4400 GPM at 700 PSI depending upon valving. It could shoot a BIG stream of water to knock down walls if necessary, something lesser trucks could not do. It responded to over 2200 fires but is now in a museum in Bay City Michigan.
PTF-18 had one run away while moored in Port Huron Michigan. Apparently the bearing seal in the turbo became worn or failed during start-up and the engine began to suck lube oil into the intake manifold past this seal. It started to overspeed, the engineer put engine in STOP mode, cutting off fuel. Since it was now running on lube oil vice fuel oil, it didn’t respond, it kept accelerating until it seized up, probably at around 8000 RPM (red-line was 2400 RPM). A memorable experience to be on board at the time, lemme tell ya. The engine destroyed itself with chunks of pistons penetrating the cylinder sleeves and other shrapnel flying around but fortunately the engine and lube oil were fairly cool and there was no fire or personnel injuries. We put in a BOAT-ALT to plumb a 200 cubic foot CO2 gas cylinder into the turbo air intakes that could be actuated remotely – that would have stopped the engine. We installed the mods on all the boats, never happened again, naturally and thankfully. See photo of an aluminum piston fragment I found in the bilge. The remains of the 3 piston ring grooves can be seen.
In the photo below, the output shaft coupling to the Vee drives is on the left and that would face forward in the boat, on the other end is the turbo-supercharger. Also at the output end are the phasing gears that collected power from each of the 3 crankshafts (two turned clockwise, one turned counterclockwise). They connected to the hydraulic clutch and various other engine-driven pumps and machinery. The Vee drives bolted to the output shafts reversed the direction of power flow to the screw shafts. This layout is common in large boats like this and was also found in the two outboard engines of the WWII, 3-engined PT boats. Their Vee-12 Packard 4M-2500 engines and Vee drives were tiny compared to this monster. This arrangement allowed the engines to be placed well aft, making room for the fuel tanks to sit near the center of gravity of the boat – keeping it in longitudinal trim as fuel was burned off. The WWII Packard’s were gasoline powered aircraft-derived engines, this beast is a diesel locomotive engine. All 7500 pounds of it although possessing a high power-to-weight ratio, a bit under 1:2 and very compact for their power. Did I mention that we had two of them? It’s difficult to judge the size of this engine in the photo although make a note of the rectangular crankshaft cover with Napier Deltic painted on it. . authors Photo:
Below is another engine (the one that is still installed starboard side in PTF-17 while in the museum at Buffalo NY). It sits under the aluminum engine room soft-patch; its girders are visible here. Note the size of that rectangular crankshaft cover next to me. The engineers took great pride in their work and this engine room was always spotless. Authors Photo
Starboard engine in 1975, the stripped down carcass remains aboard PTF-17 today. Sad…
PTF-17 Today: (August 2011) PTF-17 has been preserved and is currently on display at the Buffalo and Erie County Naval and Military Park in Buffalo, New York. She arrived at the Park in 1979. The tank landing ship USS Fairfax County was visiting Great Lakes cities on a goodwill cruise in August 1979, and carried her from her interim home at the Naval Amphibious Base in Little Creek VA. to Buffalo. She is sitting on her skid on the pier alongside the USS The Sullivans and the USS Little Rock. Her current position is 42 degrees 52.65 North, 78 degrees 52.80 West; course 315 True, speed 0 knots. She is visible on satellite photos of earth.
When PTF-17 was sent to the museum in Buffalo, it was in excellent running condition. The starboard engine had under 1000 hours on it; I was told at the time that engine was a near-record holder. The port engine probably had less that 200 hours on it – it had been replaced by us in Duluth Minnesota. The recent (2002) videos of the engine room of PTF-17 in Buffalo are a horror. The engine room appears to have been completely trashed. A big hole (tourist access?) had been sawed through the aft engine room bulkhead (!) and major parts have been stripped from this engine including one turbo and major piping, leaving it there bleeding. The turbo donut has been stripped from the port engine. A Vee drive appears to have been pulled out and then dumped on the deck plates under the main-control window. At least one generator has been removed as well as numerous control panel gauges. Wiring harnesses are dangling from the overhead. An engine control lever is missing from Main Control as well as the boats’ helm. WHY? WHO ? Stealing souvenirs is one thing but wholesale destruction?
My son and his wife visited PTF-17 in Buffalo in August 2011. The boat appears to be in “otherwise” “good” condition considering the outside location and the Buffalo weather, especially in contrast to the rest of the Navy’s PTF fleet which has largely been destroyed. Also, I am sure the Museum is strapped for funding just keeping the USS Little Rock and USS The Sullivans afloat and painted out. Other websites show PTF-3 and PTF-19 as the only other remaining Nasty-Trumpy boats. Osprey’s 23 and 26 have also survived with major modifications in civilian life.
FUN FACT: Despite the black smog behind PTF-17 in the photo of the boat crossing the wake, these boats ran very clean and were hard to detect by exhaust plume unless they were running straight at you from over the horizon on a windless day. (Check out other photo’s on this Blog). That photo was taken the day we left winter overhaul and were back in the water. In our haste to get moving, we forgot to open the large underwater main exhaust ports that were designed to deaden the sound and also to diffuse the exhaust into the water, another stealth measure. What this photo shows is the resulting black plume being forced out the low speed exhaust discharge pipes through the transom; the twin 3100 horsepower turbo-supercharged diesel engines were constipated! Opening the underwater exhaust valves cleared it right up -back to normal. Duh…
I will cover this in some detail (see the PTF Firepower Posting in this Blog), but also don’t miss Master Chief Gunners Mate Robert Stoner’s excellent descriptions in the PTFNASTY.COM website, possibly WARBOATS.ORG. He rode PTF-18 while I was the XO.
The basic weapons system included a 40 mm automatic cannon aft, a 20 mm cannon deck mounted on either side of the bridge, an 81mm mortar and .50 cal M2 machine gun combination mount on the bow, an M-60 machine gun on either side of the bridge and an assortment of small arms. These included M-79 grenade launchers, M-16 rifles, M-870 12 ga. shotguns, .45 automatics and a .38 revolver. Pound-for-pound the most heavily armed vessel in the U.S. Navy. Gunnery training was frequent, loud and impressive.
Above: Firing the 40 mm automatic gun aboard PTF-17. This gun can fire as fast as you can load the 4 round “clips”. Up to 140 rounds per minute. That’s over 2 rounds per second from this heavy gun. Boom boom boom boom boom boom boom boom boom boom etc.
Below: Pre-Fire briefing, the Mk2 Mod 0 81mm mortar and Browning M2 .50 Cal machine gun combination mount. The “sailor” right foreground was a Sea Cadet from the local unit – we gave them orientation rides as part of their program. The second “sailor” from the left was a local Marine that we captured from the Great Lakes Marine Barracks. He was pretty handy to have around, kinda like Fuji of McHale’s Navy fame. Come to think of it, I guess he was our Marine Detachment. Authors Photo Below:
Sometime later, the “Duty Marine” loads an 81mm parachute flare into the mortar. I think that is Bob Stoner in the foreground. PTF-18. authors Photo Below:
For more detail about our weapons systems, take a look here:PTF Weapons Systems
Auxillary systems included two 15 KW Onan diesel generators providing 220 VAC 60 Hz power for the boat. They were mounted in the engine room outboard of the Vee drives. One was sufficient for our needs so only one was run at a time. The Norwegian boats used Perkins diesel generators and aside from the radar systems (they ran Decca) the boats were essentially identical once the forward 40 mm gun mounts were removed from the Norwegian boats and replaced with the 81mm/.50 Cal M2 on the bow. With diesel propulsion you could run without AC power in an emergency. The boats also had 4 KW electric heaters for the crew but they were useless in the weather we were working in. Obviously not an issue in Vietnam. (The boats also had “air conditioning” in the crews quarters, but that was equally ineffective.) The Norwegians must have been tough guys. We had to haul the boats out of the water in winter when Lake Michigan froze – not much of an issue in the North Atlantic!
The main critical need for the generators was to power the two big air compressors needed to supply 500 psi air for the main engine air-start systems. You don’t crank these things with an electric motor! A long shot of canned ether sprayed into the turbo intakes while cranking fired them right up. We also had a 28 volt battery system to start the generators, run the radios, gyro, nav lighting and some instrumentation. We also had a small electric stove, sink and reefer for chow but we rarely cooked anything more serious than canned soups etc. But we had a large coffee pot!
We carried about 130 gallons of fresh water in a tank under the deckplates just aft of the forward watertight bulkhead but it just fed the galley and heads. We had 2 heads and a CHT tank up in the fore-peak – a really bad place for a CHT tank with all the pounding it took up there. So we rarely used the heads, also a major problem to pump out when alongside. There was no overboard discharge, possibly modified this way for US waters. There was a guy from NavShips (Mr. Brown – no kidding!) who visited us periodically to tweak the heads and tank. I think that tank was a post-Vietnam addition. No joy – literally.
FUN FACT: The battery compartment hydrogen gas vents were the hollow handrails on the ladder up from the engine room and penetrating the main deck at the hatch coaming. Don’t carry that cigarette while climbing thru the hatch – that’s where they vented.
Below: Some souvenirs from CRD-21, long ago and far away. The “Wings” on the Small Combatant Craft Officer in Charge insignia was a local (unauthorized – Ahem….) adaptation to recognize “water borne flight” aboard these boats. Indeed.
Typical souvenirs of the era. A Plaque from Naval Inshore Warfare Command Atlantic, our Type Commander in the Amphibious Forces in those days. Belt buckles, a cigarette lighter and a PT Boat tie clip. The tie clip was from “Boats” Newberry of “PT Boats Incorporated”, a private outfit that was restoring PT 796 in Memphis at the time. PT 796 is now on display at Fall River Massachusetts. He sent us a bunch of tie clips and “PT Boater” bumper stickers to commemorate the commissioning of CRD 21. These are the same pewter tie clips that John Kennedy handed out to his supporters at the time, a throwback to the PT-109 event.
Note that the “NAVINSWARLANT” insignia on the plaque symbolizes their common Command of the Atlantic Fleet’s US Navy SEALS (top), Explosive Ordnance Disposal (left), Coastal River Squadrons/Divisions (right) and the Inshore Undersea Warfare Group (bottom) commands. The CRD’s would eventually be renamed Special Boat Units and then again be renamed as Special Boat Teams which exist today, continuing to support SEAL / special warfare operations worldwide.
What was old has become new again.
Rear Admiral W.M.A. Greene USN, Commander NAVINSWARLANT was the guest speaker at the Commissioning ceremony of Coastal River Division 21. The other guest speaker was Rear Admiral Draper L. Kauffman USN, “The Father of Underwater Demolition”. More about him in the Coastal River Division 21 Ops post here:
PTF-18 dead astern. FORM-1, PTF-17 is Guide. Authors Photo: