Torpedo Tubes for ELCO PT BOATS

The Mk.18 torpedo tube, which launched the Mk.8 21” torpedo, was used on Elco PT boats beginning with the 77 footer and part way into the production of the 80 foot PT-103 class in its original form that I call “Mod.0”. Mods 1 through 5 followed, but you need a “Mod.0” on your 77 footer or PT-109 80 footer. And it does differ in some visible ways from Mod.1, but it’s not a well documented design.

I’ve been frustrated by the incomplete details needed to accurately model this very visible part of the early Elco PTs. A number of modeler’s drawings exist, but they don’t shed light on all the mysteries of this complicated assembly.

So I’ve assembled all the available Electric Boat drawings and the handful of historic photos that show any detail of the tubes, and built a complete CAD model of the tube in 1:1 scale. This project allowed me to fill in many of the blanks, interpolating between the existing “knowns” to flesh out possible solutions for the unknowns.

The 3D CAD model, my 2D drawings, and historic reference material is now all posted at GrabCAD:

https://grabcad.com/patrick.matthews-1/
(you may need to click on “View All”)

GrabCAD is a trusted file sharing site run by the 3D printing technology giant Stratasys. Downloads are FREE but you do need to sign in there. Note that my model is NOT directly usable for 3D printing! But a CAD designer can work up printable parts from this information.

Once there, PLEASE read the “NOTES” document which provides much more additional detail on the torpedo tube and the available files.

CREDIT: All the source information comes from the PT boat community, in Groups like this, at the PT Boat Forum, and from books by more PT boat fans. Thanks to all who keep contributing to the knowledge base!

The 3D CAD model, available on GrabCAD

Top level 2D drawing

One of the 20 available component drawings

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My Free Models on GrabCAD

I use CAD when designing my scratch built model boats, but I usually haven’t make the CAD models available. Not because I want to protect anything, but simply because building a complete and shareable CAD model and associated 2D drawings can be as much work as building the actual model boat!
I’m going back and rectifying this where possible. In addition to free standing CAD models I’ve made and shared before (where I haven’t actually built a physical model), I’m now completing other older CAD models of my RC boats and uploading them for free sharing on GrabCAD:
https://grabcad.com/patrick.matthews-1/models

The most recent is PILAR, Hemingway’s boat. And I’m currently working on a PANAIR seaplane tender- the boats that serviced Pan American “Clipper” stations around the world.

PANAIR 36 foot seaplane tender, on the digital ways.

PILAR on GrabCAD: Here is a 3D model that you can download, or just spin around for viewing on the GrabCAD page.

One of the several 2D drawings for PILAR, available for free download.

Crowley Invader

Latest job off the bench

My latest completion, a 1:32 Invader class tug built on the available Harbor Models fiberglass hull. Deck, cabin, running gear, and all fittings were self-made using traditional techniques and extensive 3D printing.

All lit up

In the marine test facility

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Pilar, again

Lighting makes all the difference! My brother Wil is a photographer, and he did a quick shoot of Pilar. In my garage, with whatever was available to make a “studio”. He did have a “softbox” with strobe for the lighting, and a serious camera.

The set up, which included 3 yards of black fabric from JoAnn’s

A couple more nice shots:

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3D Model of San Francisco Fire Boats

SFFD fire boat now on GrabCad

It’s 1909, and San Francisco is cheering the launch of twin new fire boats, the “David Scannell” and the “Dennis T. Sullivan”, named for two previous fire chiefs. Sullivan was mortally injured in the disastrous earthquake and fire of ’06, a disaster which launched the installation of improved fire fighting resources for the city. The two new fire boats were part of the new system, as they could connect their pumps to numerous shoreside manifolds.

I have drawn up a 3D CAD model of the boats along with 2D CAD drawings, and assembled my research notes and some 50 photos into a set which can be downloaded for free from GrabCad:
https://grabcad.com/library/sffd-fire-boats-1909-1

One of the four sheets of 2D drawings

If you download the set, be sure to review the 37 page document full of my research notes. And if you build a model, please send pics!

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Hillman Towboat Model

Back in 2015, I wrote about researching towboats from the Hillman Barge Company. And late last year I got started on building a model of the 115′ towboat, which I show in this detailed build post. I do get easily distracted, so I’m on yet another project right now, leaving the Hillman looking something like this:

Hoping to get back to it soon!

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3D Model of Santa Fe Tugboat

While I continue to tweak the CAD model of the ATSF tug “Edward J. Engel”, I’ve gone ahead and posted a downloadable 3D CAD file on GrabCAD:
https://grabcad.com/library/edward-j-engel-1
You can spin it around and download it. See the notes at GrabCAD for more details.

EDIT: 6/1/2019: The CAD file at Grabcad may be updated at any time, and I just did. Now on v179, with numerous corrections and improvements, thanks to the new set of drawings from Stanford.

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Santa Fe Tugboat Edward J. Engel

I stumbled across an image of the Edward J. Engel a few years ago, and have been chasing leads ever since. Not much info was readily available, but we have uncovered rudimentary plans that were published in 1945 marine journals. That and a few photos that have surfaced are enough for me to develop a 3D CAD model and plans.

Engel and two other ex-Army LT tugs were used by the Santa Fe to ferry cars across San Francisco Bay into the 1970’s. Engel was new bought and seems to have been a showcase of design. Obviously, she was streamlined, and originally she carried full “warbonnet” livery. Powered by an efficient Skinner Unaflow steam engine, she also had other interesting technical features. For example, she carries no fenders or unsightly rub rails, as she was built with a 4 foot deep sheer strake of massive 1-1/4″ steel!

For convenience, I am documenting the project and making the information available on a Facebook page:
https://www.facebook.com/groups/edwardjengel

Just yesterday, I posted the first installment on distributable drawings, my rendering of a lines plan set. But again, go to the FB page for the full size docs!

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Library

My modest library of boat books

Where would I be without all my reference materials? Sure there’s plenty online, and plenty of digital content saved on my disk, but there’s nothing like the old books and magazines. And I’m not even showing the plans and drawings, that’s another pile!

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Hemingway’s PILAR in 1:12

I’ve been posting elsewhere for the last few years, but I need to update this column. Here’s my latest build, Hemingway’s PILAR. A more complete set of images and a build log for the model can be found on RC Groups.

The model was designed in CAD from photos and one profile image in an old Wheeler sales brochure. I know the model is not correct in many areas, but I believe it is more correct than many others. This may be the only model around that shows the forward cockpit, which is now decked over on the boat at Finca Vigia. And most modelers don’t understand the rudder footing, which is missing on the museum boat, and which is a hallmark of 1930’s cabin cruiser design, along with its extended skeg. We also see the auxiliary trolling drive, which Hemingway had installed as a special by Wheeler.

A handful of 3D printed fittings, both in plastic, and as investment cast bronze from printed waxes, complete the model. But the main structure is all hand built in a variety of woods. All of the exposed cabin wood is cherry, which I find to better simulate the original mahogany in this scale.

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