The PT Boat Forum

Forum Category: PT Boats of WWII

Forum Name: PT Boats - General

Topic: ELCO torpedo tube training gear

A couple days ago, a modeler asked me about the training gear on the early 80' ELCOs. He mentioned that he had gotten information on here that some of the first boats used the type of training gear used on the 77' ELCOs. This is something I've never heard of and the ELCO drawings I've looked at don't seem to support it. What I am missing?

Posted By: alross2 | Posted on: May 1, 2021 - 10:36am
Total Posts: 930 | Joined: Oct 30, 2006 - 8:19pm

Hi Al . . .

It’s been a while, nice to see your post. There have been many torpedo questions on the forum over the many, many years. I’m guessing one of the several post concerning the torpedo tube training gear was this one here, where I was the lead on the discussion after receiving an email about the subject.

Link: [url][/url]

The post started about 6 or 7 years ago, with the Elco 77 and 70 boats. It later progressed to early Elco 80 boats, but not much discussion. There are no Elco 80 engineering drawings that gave a clue as to installation, timming, or application of the “ Inline Drive or the 90-degree drive. “ At least none of which I have found. However your detailed engineering drawing of the the Mark 18 tubes clearly calls out the training drive types and parts. The biggest aid in making our assumptions, and that is what they were, assumptions, were based on photographic evidence. Not any detail engineering knowledge. We only discussed what we could see with our own eyes. This was that early Elco 77 and early Elco 80’s were using the inline tube training gearbox. With later photographic evidence showing later Elco 77’s and Elco 80’s were then using the more convent 90-degree gearboxes. See the photos below. And please read the reference link, I would love to know your opinion on the subject.

I hope all understand the hundreds and hundred of drawings that we now have, are far from all of the drawings that had to have been created just to make the Elco boat regardless of size. Also the thousands of DCN (Drawing Change Notices), TOD (Technical Order Dilemma) and the TOI (Technical Oder Instructions), all of which were needed to rectify manufacturing and Navy concerns and orders. I’m getting pretty old, to think I will ever make it to ARA at College Park to throughly score there records for more . . . .

Hopefully, I’ll post this answer post on the original post mentioned above to advance it to the top of the Forum here.

Reference Photos . . .



Dick . . .

Posted By: Dick | Posted on: May 1, 2021 - 3:41pm
Total Posts: 1313 | Joined: Aug 27, 2006 - 6:36pm

Dick, I contacted Al thru a different site, asking about the inline training gear, I wanted to know about how shaft entered the cabin ? was there a cover, mount, bracket ? and what it looked like , I referenced your post Oct 14 Stewart Hurley told me about the 105 not being fitted with a 90 deg gearbox because I originally had the crank handles stowed on the day cabin roof., which I removed and rebuilt the training gear based on the inline type I followed your drawing and Pictures from Jerry Gilmartin. I know you guys are the experts here, but did I miss something ? Mike

Posted By: Grady | Posted on: May 2, 2021 - 2:33am
Total Posts: 144 | Joined: Oct 2, 2018 - 8:04am

Hi Dick,. Thanks for your, as usual, great response. This is a curious one and I'd love to see more. I have a number of ELCO drawings of several gear boxes, some of which are dated. I should go back and look at those and see where they fit in the production of the 80' boats. I'm having a hard time figuring out where they exited the chart house given its internal structure. I have them scanned. Is there a way to upload them here?


Posted By: alross2 | Posted on: May 2, 2021 - 7:24am
Total Posts: 930 | Joined: Oct 30, 2006 - 8:19pm

Al & Grady . . .

Al, if your scans are image files like .JPG you can upload them when you post a message. Next to the message reply box is an orange " Upload Images". However if they are .PDF or .DOC, email them to me and I'll do something with them to get them posted.

Al & Grady . . . you'll have to give this old man some time, and I will see what I can better define.

Please make sure you go through the Linked forum posting above, It should give a better understanding.

Dick . . .

Posted By: Dick | Posted on: May 2, 2021 - 11:48am
Total Posts: 1313 | Joined: Aug 27, 2006 - 6:36pm

The Elco drawings of the 90 degree gearbox seem to be dated Oct 1942 so this might give an indication of the timeframe when they were fitted. I have never seen a photo of the early inline drives being operated on the 80' boats so not sure of the tools used. I don't think they operated through the cabin walls like on the 77' though IMHO.

Best Regards,

Posted By: Stuart Hurley | Posted on: May 3, 2021 - 2:00pm
Total Posts: 247 | Joined: Mar 19, 2013 - 3:32am

I have a 90degree drawing 1798-14 dated 5/29/42. PT103 was placed in service 6/2/42.

Posted By: alross2 | Posted on: May 3, 2021 - 4:41pm
Total Posts: 930 | Joined: Oct 30, 2006 - 8:19pm

It's hard to tell with the training gear sheets of the tube drawings, the Mod 0 has 4 sheets for it but the first is missing. I can't tell how the short cranks were used, a universal joint, or maybe 2, is / are also laid out, maybe one was used between the crank and the end of the acme screw. Although the right angle gear drive used a u-joint between the gearbox and acme screw so maybe it is that.

From what I can tell on this rather low res shot of the 105, there are no openings for a crank rod going into the chart house:


This shot of PT 111 shows the inline style, looks like there would be plenty of room for a short crank with a universal joint on the end:


Posted By: Jeff D | Posted on: May 4, 2021 - 10:15am
Total Posts: 2066 | Joined: Dec 21, 2006 - 1:30am