The “Other” PT Boats

Updated:  10Oct17

The Vietnam-era PTF’s were similar in concept to the WWII PT Boats so let’s look at those Elco’s and Higgins boats a bit. Starting off with the 1942 Motor Torpedo Boat Tactical Orders and Doctrine Manual as declassified.
From Historic Naval Ships Association

Military Characteristics:

PT 103 type-PTs 103-196 (Elco Boat Works). Length 80 feet 3 inches; beam 20 feet 10 3/4 inches; max. draft 5 feet 3/4 inch; displacement 100,000 pounds.
(a)GUNS:

Four .50-caliber air-cooled B. A. machine guns, two twin, hand-operated scarf ring mounts.
One 20-mm. Oerlikon mount.
One .45-caliber Thompson submachine gun.
Two .30-caliber Springfield rifles.
Thirteen .45-caliber Colt pistols.

(b) AMMUNITION:
20-mm.:

Allowance-1,200 rounds.
Carried on board-480 rounds in eight 60-round magazines (ratio one Tr. to one H. E.).

.50-caliber:

Allowance-10,000 rounds per gun.
Carried on board-1,000 rounds per gun belted (ratio one Tr. to one A. P.) in four 250-round magazines per gun.

.45-caliber:

Allowance-4,000 rounds ball.
Carried on board-All.

.30-caliber:

Allowance-1,200 rounds. Carried on board-All.

(c) TORPEDOES: Four 21-inch Mark 8-3 C and D, speed 27 knots, range 13,500 yards. (If depth charges and 20-mm. gun are mounted, only two 21-inch torpedoes are carried, the others are held in reserve.)

(d) TORPEDO TUBES: Four 21-inch Mark 18-1 bow launching (only two tubes mounted if 20-mm. gun and depth charges are mounted).

(e) DEPTH CHARGES: Eight Mark 6 (300-pound charge).

(f) DEPTH CHARGE RACKS: Eight individual side launching type “C”.

(g) SMOKE SCREEN GENERATOR: Mark 3, capacity 32-gallon F. S. mixture.

(h) FRESH WATER: 200 gallons (approximate).

(i) FUEL: 3,000 gallons high octane gasoline.

(j) LUBRICATING OIL: 30 gallons.

(k) FRESH PROVISIONS: Four days rations for nine men and two officers.

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(l) COMMUNICATIONS: Blinker tube, semaphore, M. P. signal light, 8-inch searchlight, TCS voice radio set, range about 75 miles.(m)RADIO DIRECTION FINDER: One R. D. F. set per boat.(n)MACHINERY:

Maine engines-three 1,200-hp. Packard 4-M2500.
Auxiliary generator-two 1/2-kw. water-cooled generator.
Power-Four 6-volt storage batteries 24 volts.
Shafts-Three shafts, three propellers (all right hand).
Rudders-Three rudders, mechanical steering.

(o) CRUISING RADIUS (see table in back of book):

Full load maximum speed ____ knots, ____ miles.
Full load maximum sustained speed ____ knots, ____ miles.
Full load one engine ____ knots, ____ speed

PT Boat Radioman

 

Note Paragraph 5210:  All crew members must know Morse Code

 

CHAPTER 2. COMMUNICATIONSDoctrine and Practice5201. Communications in motor torpedo boats are difficult even under good conditions due to the unstable platform, exposure of personnel to seas and weather, and the limitations of the facilities available on board.5202. Facilities.-The following facilities are available for communications:

(1) Radio telephone and telegraph with limited output range and power supply.
(2) Signal flags.
(3) Semaphore flags.
(4) M. P. (multi-purpose) signal light.
(5) Blinker tube.
(6) Searchlight.
(7) Arm signals.
(8) Verys pistols.
(9) Code and cipher publications similar to those carried by aircraft.
(10) Radio direction finder.

5203. Radio transmissions.-In view of the necessity for radio silence during wartime or the transmissions of radio messages in code, use of the radio will normally be restricted on motor torpedo boats and confined to very urgent messages. However, during the progress of a motor torpedo boat attack on the enemy, or if being attacked by the enemy, full use of the radio should be made, if it will add to the effectiveness of the attack or counterattack.

5204. Visual communications.-Visual communications should be used whenever possible. During daytime operations when motor torpedo boats are in small compact formations, hand and flag signals will normally be the primary method of communicating between boats. At night, when the security of position will not be disclosed, blinker tube or signal light will be necessary. If light signals cannot safely be used, boats will close and communicate by word of mouth.

5205. Encoded messages.-When encoded radio communications are permitted and the necessity for communications between boats is urgent, it will be found expeditious to arrange certain



code words in advance to denote phrases appropriate to the particular mission on which to be engaged. This will preclude use and probable compromise of, official code publications which ordinarily cannot be conveniently carried or used aboard motor torpedo boats. For communicating with other units of the fleet, the aircraft signal book and contact report pads are adequate and should be carried on board. 5206. Authenticators.-Radio personnel should develop the habit of recognizing the voices of their contemporaries on other boats, thus eventually eliminating the need for authenticators when orders are transmitted by radio from one boat to other boats.5207. Conservation of power.-(a) The necessity for conserving power when operating in motor torpedo boats and the importance of keeping radio equipment in an excellent state of repair cannot be too greatly emphasized. Emergencies may occur requiring continuous operation of the radio for long periods. Also circumstances may arise where the state of readiness of the radio may determine the destruction of one’s own forces, an enemy force or the destruction of an individual boat and crew.

(b) Maintenance and periodic overhaul of material should be made in accordance with the prescribed check off lists and weekly reports.

(c) Effective safety measures should be continually employed to prevent the following:

(1) Shorting of wires and sparking of loose connections.(2) Injury to personnel from dangerous voltages in antenna and transmitter.(3) Creation of explosive hydrogen gases in storage batteries due to improper ventilation.(4) Static electricity and consequent sparking as a result of broken bonding.

(d) Radio direction finder equipment should be calibrated as soon as the boats are received and calibration curves should be kept posted in the immediate vicinity of the equipment.

5208. Standard procedure.-

(a) Standard procedure is absolutely essential and must be adhered to by personnel operating the radio. Some of the more important details of proper procedure are given below. A complete guide is given in Naval Communication Instructions.

(b) In wartime encoded call signs are assigned to and used by each boat to preserve secrecy of identity. The examples below

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give the regular calls for simplicity: Assume the PT 1 wishes to call the PT 2 and order it to return to base.

Step 1-2 from 1, 2 from 1, answer.
Step 2-1 from 2, go ahead.
Step 3-2 from 1, return to base, acknowledged.
Step 4-1 from 2, wilco.

(c) The above steps illustrate the following basic principles:

Step 1-The addressee’s call is always given first. Answer is used when trying to establish contact with another boat.Step 2Go aheadis used when contact is established and when either the addressee or the sender is ready for the other party to “come back”.Step 3Acknowledge is standard phraseology for requesting acknowledgment.Step 4Wilco means “I will comply” and is used by a boat on receiving instructions from a senior boat to carry out an order. The use of wilco should not be confused with that of the word roger. Roger is used merely to acknowledge that a message is received; it does not imply the intention to comply.

5209. Operation.-Efficient radio communication requires constant effort to eliminate the following practices:

(a) The use of unauthorized procedure which permits the enemy to associate types of craft with the operating peculiarities of the personnel.(b)Unnecessary use of the radio. This is the most common form of bad communication practice. It is dangerous in that it permits radio direction finding and consequent compromise of security of position.(c)Excessive test counts. Test counts should be held to an absolute minimum.(d) Operation of the radio by inadequately indoctrinated personnel.

5210. Personnel.-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. Each man must know MTB communications procedure as well as the basic principles of sound communication practice set forth in Communications Instructions. The importance of training and disciplining operating

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personnel in the developing of sound communication habits cannot be overemphasized. In the last analysis the standard of radio communication efficiency will largely depend on the intelligence of the personnel and therefore selection of only the best qualified is of paramount importance. 5211. Recognition and identification.-(a)Because of the similarity of the general appearance between MTB’s and submarines, MTB’s are not infrequently mistaken for enemy submarines by friendly surface vessels and aircraft. It is, therefore, of the utmost importance that MTB personnel be trained to use maximum speed in identifying themselves. Emergency recognition signals and Verys pistols should always be kept at hand to avoid a moment’s delay when needed.(b) The communication officer on MTB’s should have made out daily, the following lists for all MTB’s in the squadron:

Four days recognition and emergency identification signals.
Encoded calls.

No boat captain should get underway without having these lists aboard and he should be personally responsible for turning the list in when his boat returns to base.

5212. Confidential publications.-Confidential publications carried on board MTB’s should be carried in a locked W. T. case which will readily sink when thrown overboard, in case the boat is captured or destroyed. These cases should be turned in to commanding officer upon return to base.

5213. Security.-The highly confidential nature of certain military characteristics of motor torpedo boats must be guarded against compromise. New personnel, personnel under training and civilian contractors working in an official capacity with motor torpedo boats must be thoroughly instructed regarding the importance of preserving the inviolability of confidential information regarding the size, seaworthiness, cruising radius, speed, armament, armor and operations of motor torpedo boats.

PT Boat Radio Transmitter - TCS

PT Boat Radio Transmitter - TCS

Above: My TCS Transmitter on temporary display at the local Veterans Memorial Building for Veterans Day 2013.

After action reports from PT Boat squadrons in the South Pacific / Rendova AOR for example include a statement about communications. Those indicate that TCS radio comms between the boats and from the boats to base were generally “satisfactory” however there were failures as well. Enemy jamming was noted and was effective at times on 3785 kc, one of the operational frequencies in use. When TCS/HF radio problems occurred, the reports noted that TBY’s were used to good effect however weak batteries, beyond their “use by” dates, were a constant problem. Reference 54.