The PT Boat Forum

» Forum Category: PT Boats of WWII

» Forum Name: PT Boats - General

» Topic: Sextants on PT Boats?

Hello everyone! I was wondering if either Elco or Higgins were supplied with a Sextant for the boat and also with a Boat Chronometer? I looked at the "PT Tactical Orders and Doctine" Book and the "Elco Builders Specifications" books on the HNSA website, but I could not find any listing of either. I know the Chartboards were supplied with a Parallel Motion Protractor (PMP) as well as Parallel Rules and Navigators Instrument set, (Dividers etc) but have never seen them listed anywhere either for that matter. I have seen photos of the PMP and Rulers being used on PT Boats however, by the QM but not a Sextant. Is there a list somewhere that shows all of the equipment that would have been supplied on board the newly built PT Boats? (Kind of like a modern day COSAL?) One thing I did see on You Tube was the old PT Boat Propaganda Movie called "Devil Boats" it shows the main character, the Officer "Bob" learning how to use a Sextant while he is at the Melville Training Center. So let me know if you have any ideas about this! We want to add this sextant to our list of needed equipment if it is accurate. Thanks Jerry PT658 Portland, OR

Jerry Gilmartin

Posted By: Jerry Gilmartin | Posted on: Aug 23, 2010 - 7:42pm
Total Posts: 1227 | Joined: Oct 8, 2006 - 11:16pm

Hey! I was hoping somebody would have an answer for me? How about Earl or CJ or Ted? Or Dr Ross? Frank? Will? Garth? Steve Nugent, Jim Stanton? Does anybody have any ideas about this? Please? I dont even know where to look for the answer without your help! Jerry

Jerry Gilmartin

Posted By: Jerry Gilmartin | Posted on: Aug 25, 2010 - 6:14pm
Total Posts: 1227 | Joined: Oct 8, 2006 - 11:16pm


The boats had chronometers provided by the Bureau of Ships. They may not have been assigned to the boat but rather to the Quartermaster .I am not sure. But, just as important, each Quartermaster had a "comparing watch" also issued by BuShips. I have photos of both from the Quartermaster of PT 113 in Division 17, the first US Navy contingent into New Guinea in December, '42. The chronometer was mounted into a very nicely made wooden box, probably Philippine Mahogony, with a nicely fitted cover, as well. The comparing watch was in a simple chamois type sleeve within a cardboard box. Navigation required such precision that the comparing watch, as I understand it, was used to verfy the accuracy of the chronometer. I suppose if there was a descrepancy, then the QM would have to determine which, if either, was correct. But, I'm no navigator.

I think I remember a reference to the sextant in a book by Lent called simply P.T. Boat. I looked quick but there is no Index so I'll check again within the text asap.


Posted By: Allan | Posted on: Aug 25, 2010 - 6:23pm
Total Posts: 161 | Joined: Sep 18, 2007 - 7:07pm

The MTB Manual mentions a sextant in passing. Rappleyea, in NAVIGATION WRINKLES FOR COMBAT MOTOR BOATS (published by Higgins) talks about the use of sextants. This cartoon shows a sextant being used:[IMaGe][/IMaGe]

A sextant would probably be a Title B item, which would be listed on an Allowance List. I have allowance lists for ordnance, but not the general equipment list. Mavbe Germantown has a copy.

Al Ross

Posted By: alross2 | Posted on: Aug 25, 2010 - 7:32pm
Total Posts: 904 | Joined: Oct 30, 2006 - 8:19pm

Thanks you guys! Al I loked in that MTB Manual [url][/url] and searched for the word "Sextant" and also for "star sight"and thats how I found it! Thanks so much for the help. It does indeed list it under examples of Title B Materials, along with a Chronometer and etc. The MTB Manual also has a section that requires Officer Trainees to be able to "shoot a star sight or if no opportunity shoot a sun sight" I think it is in the appendix 1 of the book.

Here is the part: on page 304
SECTION B. INSTRUMENTS USED IN PILOTING AND THEIR OPERATION (6) The Sextant: Sextants are used mainly for celestial navigation. However, they are useful in piloting for the measurement of horizontal angles between objects, after which the angles are laid off on the chart to fix the ship's position. Occasionally, vertical sextant angles are taken to determine the ship's distance off a chartered object.

Also in the Stores Section of Part 1 it talks about Title B Material

MTB officers, in the course of routine duties, are principally concerned with Title B articles.....the officer custodian may then use the copies retained on board to turn over custody to appropriate members of his crew. For example, the quartermaster should take custody of the SEXTANT, chronometers, and navigational instruments. The men who take custody sign the copy of the card in the provided space, and are then responsible to the officer custodian. ....In PT boats, an inventory of all Title B equipment will be made by each boat captain once each quarter and entered in the deck log .


II. Seamanship and Navigation Practical factors.--
* Get under way from the dock and make a landing.
* Plot, satisfactorily, a 100-mile cruise on a chart in coastal waters, noting compass courses to be steered.
* Take a star sight, identify star, and work out for line of position (sun sight if no opportunity exists for taking star sights)--officers only.
* Demonstrate how to tow another PT boat.
* Anchor a PT boat.

So I think this is a pretty good indication that they actually did have a Sextant on the PT Boats! Thanks again for you guys response! Jerry

SO my question is still, especially for the WW2 PT Boat veterans out there (especially QM!) did you ever use or see used a Sextant on your boat?

Thanks again!

Jerry Gilmartin

Posted By: Jerry Gilmartin | Posted on: Aug 25, 2010 - 9:11pm
Total Posts: 1227 | Joined: Oct 8, 2006 - 11:16pm


I have never heard of a sextant being used on a PT BOAT. They did teach the use of a sextant at the MTBSTC, but I do not think they were used after that. In my contact with Arthur Frongello, he had mentioned to me that small boats used Piloting (in sight of land) and dead reconing (propeller turns coverted to knots and compass heading over time to determine position). Many boats would use Radar at times to bounce the signals off known mountain peaks. Many used dead roconing and radar most of the time. By the way Arthur mentioned to me that he never saw a sextant after training. I guess this does not speak for every boat, but at least for PT-302 when Arthur was aboard............

Posted By: Frank J Andruss Sr | Posted on: Aug 26, 2010 - 1:27am
Total Posts: 3179 | Joined: Oct 9, 2006 - 6:09am

So what else is new with the PT Navy? Some had sextants, some didn't, etc., etc. I seem to remember a story by Kelly about getting a hard stare from an admiral aboad the 34 boat during the breakout when he used the crook of his arm to shoot a "bow and beam" bearing off a nearby island (or something)...


Posted By: Will Day | Posted on: Aug 26, 2010 - 11:27am
Total Posts: 1896 | Joined: Oct 8, 2006 - 4:19pm

Strictly for Those Who Collect Trivia:

The term "dead reckoning" comes from very early sailing terms as found in ships' logs of the time, where the entry being made was shortened in the interests ofboth time and effort, overall. The actually entry referred to "deduced reckoning" but was often abbreviated to "de'd. reckoning".

Beleive it or not!


Posted By: Allan | Posted on: Aug 26, 2010 - 2:21pm
Total Posts: 161 | Joined: Sep 18, 2007 - 7:07pm

I have to agree with Frank’s explanation, while celestial was taught at Melville; I don't believe it was used afterword, except by those that enjoyed it and were comfortable with it. In Jack Searles book, he mentions the trip (Melville - Panama) he did taking 59(Mills), 60(Searles) and 61(Warfield) down to RON 2 and 3(2). Warfield was into celestial and that’s the way they went on that trip. I also know Ed Hoagland RON 24 used a sextant and did celestial navigation.
As for out in the Zone,I am sure some did it simply because it is a use it or lose it skill. But they mainly did DR or Radar, which was fine for their work around the islands, the open ocean transits they did, like moving from New Guinea to the Philippines, were usually in company of a tender, so for practical purposes all they really had to do was follow the big ship.
Take care,
If your asking for PT 658, I wish you asked this 2 years ago, I had a sweet/mint 1943 sextant with all attachments and original green felt lined case that belonged to my Dad, I would have been happy to send it to you guys.

Posted By: TED WALTHER | Posted on: Aug 26, 2010 - 5:22pm
Total Posts: 2887 | Joined: Oct 16, 2006 - 7:42am

Thanks you guys! I found a guy who is willing to donate one next thursday! I guess it is good to keep asking! We also have a line on a PT Boat Chronometer! I will take photos and post them when it becomes a reality. Jerry

Jerry Gilmartin

Posted By: Jerry Gilmartin | Posted on: Aug 27, 2010 - 10:45pm
Total Posts: 1227 | Joined: Oct 8, 2006 - 11:16pm

Hey guys,

I was at the Archives on Friday looking through the log books of PT-81 and stumbled onto this entry:

March 31, 1944 - Telescopic sight for sextant returned from optical shop No. 3.

So it seems they had a sextant.



Posted By: 29navy | Posted on: Aug 29, 2010 - 1:48pm
Total Posts: 510 | Joined: Dec 28, 2006 - 3:02pm

Hey thanks Charlie! Also to Ted for that info. I was looking at this websites News Section and under the heading "Artifacts Donated" it says the following:

see below:

"Here are a few items we would like to acquire: Radio and Radar manuals, Compass, Sextant, Barometer, Volume 1 Building the Navy's Bases, Abandon Ship Kit, Torpedo Director MK31, Pistol Signal AN-M8, Coffee Maker Silex type A, Anchor (25 lb)."

So I guess the PT Boats Inc Museum also wants a Sextant! I will keep my eyes open for others that become available. Jerry

Jerry Gilmartin

Posted By: Jerry Gilmartin | Posted on: Aug 31, 2010 - 11:23am
Total Posts: 1227 | Joined: Oct 8, 2006 - 11:16pm

I very seldomr saw a sextant in serious use on board a PT Boat. I considered myself capable of using a sextant, promotions contained that capability and officers respected that a QM could navigate with the stars if necessary. Inherent in celestial was a xery accurite timepiece. The Chronominator was that timepiece. It was highly accurite when kept so but most of them could not be suddenly used along with a sextant should one suddenly located.. So a Chronometer was a good watch to hsve, but a sextant was only good soviinir f you had the guts to try to steal one..

Posted By: BobPic | Posted on: Aug 31, 2010 - 4:37pm
Total Posts: | Joined: Unregistered

Thanks BobPic! I was hoping to hear from the PT veterans that were there! I really appreciate your response. Most of the PT Boater veterans I have spoken to personally were not QM's so your point of view as a QM is especially pertinent. Thanks again. Jerry

Jerry Gilmartin

Posted By: Jerry Gilmartin | Posted on: Aug 31, 2010 - 7:27pm
Total Posts: 1227 | Joined: Oct 8, 2006 - 11:16pm

Update: Photo of Sextant and Chronometer recently donated to PT658 along with updated historically correct Chart board

We were donated these items by some local PT Boat enthusiasts. The chart on the chartboard was donated by Frank J Andruss. (This is a laminated copy, the real one is stored in a safe place.) I just wanted to show you how they look on board the PT Boat! Thanks to all of you on the message board for your help in deciding if this was the right stuff! Jerry

Sextant and Chronometer

Chartboard with Elba Island Invasion chart used on PT Boat.

Jerry Gilmartin

Posted By: Jerry Gilmartin | Posted on: Nov 7, 2010 - 4:03pm
Total Posts: 1227 | Joined: Oct 8, 2006 - 11:16pm

Jerry, I have touched on this subject before as a "default navigator".There were a few navigational quality swxtants arounnd but NONE were used within the squadrons for navigation. They were used by the base to fix the exact location of operations aand by the sea bees in planning and laying out bases, docks, etc. Why? Using a sextant requires a very steady platform from wiich to take accurate readings. Can't be done from the deck of a PT underway. A sextant even used by a skilled navigator can not be relied on for an accuracy of better than 8-10 miles.Not good enough. A good star fix takes too much time. A very precise clock is required. Most PT's provided with chronometers did not properly care for them. I am very sure there were some sextants around, mostly as officers toys, but they were never used for boat navigation. Subject to superior intelligencs and higher authority, I say now that NO sextants were ever used as a tactical device in the PT boat service.

Posted By: BobPic | Posted on: Nov 8, 2010 - 12:12pm
Total Posts: | Joined: Unregistered

Thanks Bob!
I agree with you sentiment, but I was not going to "look a gift horse in the mouth". I understand the fact that Sextants were seldom used on board the PT Boats, but I did find (along with this message board's help enough instances where they were used (although rarely as you state), more like an officers toy. However, I have read more than one PT Boat deck logbook that states every day "Wound the Chronometer" (See PT 127 logbook and PT171 Dyna-Mite" logbooks. This begs the question, why did they even have a chronomter if they did not have a sextant to go along with it? You cannot perform celestial navigation without both instruments. Plus the sextant (eg Taking a star sight or a sun sight) is mentioned as required training for PT Boat Officers at Melville.Sextants are also used as the primary example of Title B equipment that should be placed in the custody of the PT Boat Quartermaster in the "Motor Torpedo Boats Tactical Orders and Doctrine" Manual. So yes I am sure that 99% of all PT Boaters never actually had the occasion to use the Sextant, but at least a few may have been around on different boats. Thanks for posting your comment. Jerry PT658 Portland OR

Jerry Gilmartin

Posted By: Jerry Gilmartin | Posted on: Nov 8, 2010 - 12:38pm
Total Posts: 1227 | Joined: Oct 8, 2006 - 11:16pm