@Mirangi Agree that variations are likely but these circular items seem to have some sort of “hanger” arrangement.

The hanger is the push-rod control for operating the butterfly valves. It is there on all Elco boats.

@Mirangi The mufflers shown on your pic do not have the characteristic three dimples across the expansion chamber, and so are not the design which we associate with the standard Elco. If I had to speculate, I'd suggest that they are lorry or bulldozer mufflers, pressed into service because the last set corroded in the salt water and there were no Elco spares available at the time.

Note that the deck equipment of each boat is different and differently placed. It has been said that no two PT boats were alike 6 months after leaving the factory, and this seems to be a good illustration. Interestingly, the boats, though of a late series, appear to have wood planking decks (I always understood them to have plywood sheet) and do not seem to carry the green camouflage that we often see. I made my EeZeBilt PT boat with deck planking because I thought it looked more attractive - looks as it it was actually accurate (in some cases...).

Agree that variations are likely but these circular items seem to have some sort of “hanger” arrangement.

You could be right and perhaps these were sourced from a different vessel/ truck / tank / other when originals needed replacement or these were quieter than original.

I guess we will never know.

1: Pic of the PT109.
2: Pic of my PT61, 1/20 scale model (about 10 years ago).
3. Protector for the transom (mufflers, props, and rudders for my PT61.

Update: The mufflers were mounted to the transom via two brackets (which might have been welded to the mufflers). Seems the mufflers and exhaust designs were very similar for most of the boats. Checkout: https://www.pt-boat.com/muffler/muffler.html

@Mirangi Great pics!

The circularity may be a photographic effect, of course. But if it isn't, I would not be surprised to find all sorts of minor variations on these boats. Many sub-contractors would have made parts, and those mufflers must have been changed frequently. I can't see them lasting long in that environment.

Interesting radar on one of the boats - not a shape I have seen before. And each boat has a host of detail differences. They seem to have different cowl vents, for a start...

Hi, still chasing info on the PT Boat mufflers when I came across this photo.

These 3 boats seen to have an almost circular housing which seems to enclose each muffler.

Am I deluding my self here or is this really there?

Any ideas on what these are for?

Seems odd for 3 boats to have these, making it unlikely just a local mod!!

@jumpugly I do like 1/24 scale when moving from inches to mm's!

@jumpugly These boats are not intended to be fine scale - they are 'starter boats' for beginners, so the workmanship will never be perfect! They are designed to give a 'reasonable result' for people with a low skill level - typically children around 8-10 years, who would like to make a model boat but don't want to spend a lot of time and don't have expensive tools or facilities. The 'egg-box' structure means that they can be assembled without a building board (though a flat surface of some kind is helpful). Typically, a bedside table or desk...

The original EeZeBilt range were made by Keil Kraft in the UK in the 1960s. I have added to the range 50 years later with some bigger designs more suitable for radio control, as the 'EeZeBilt 50+' range. You can download the free plans for them here: http://eezebilt.uk/plans.html and the 50+ range includes build logs and in some cases 3-D print files.

Some pics: http://eezebilt.uk/front.jpg http://eezebilt.uk/20260614_151602.jpg http://eezebilt.uk/PTB10.html

Points well taken DodgyG. Beautiful workmanship on your boat! Send more pix!
😉

@jumpugly I can see some possibility for confusion here. The mufflers comprise an oval expansion chamber, with an output pipe below and an inlet system with a butterfly valve above. My mufflers were 1" in total size - the oval expansion chamber was about 3/4", which would make that chamber length about 36" in full size - with 8" for the valve above and a 4" stub exhaust below...

My semi-scale EeZeBilts are generally made with eyeball estimations rather than measured scale, but they seem to come out quite close. Here is a shot of the stern of a restored Elco - https://www.williammaloney.com/Aviation/PTBoat/PTBoatStern.jpg
and here is a pic of the stern of one of mine: http://eezebilt.uk/img_2344.jpg

I think they look quite similar. Note that in real life all these parts would have been made by different sub-contractors, and so non-critical measurements would have probably been slightly different. And of course continuous development would have occurred, changing various dimensions as a result of combat feedback...

BTW: Sasa Drobac at Di Stefan 3D Print has helped me out from time to time...his team prints in every scale if you ask and they have a mountain of PT Boat parts. Not always in love with their prices as they vary wildly, but it's a great site all the same to see what they've got. Note: They've farmed out to work to 3D print shops in China and shipping can be slow. Also try "Matthews Model Marine" by Patrick Matthews.

https://distefano3dprint.com/products/1-20-usn-pt-boat-109-mufflers-set?variant=40403649429569&utm_source=Pinterest&utm_medium=organic

Morning Steve:

Using my favorite scale converter, Dodgy Geezer's hugely helpful numbers in 1:24th scale work out as such...

15 inches = .5833 inch = 15.875mm
46 inches = 1.9167 inch = 48.6833mm
8 inches = .3333 inch = 8.467mm


https://www.ginifab.com/feeds/cm_to_inch/scale_converter.html

Hi,
Yes I have this article and it is excellent with a great way of producing 6 of these all the same, but it does not have any dimensions.

AI is effectively a more sophisticated Google look-up, and is good for this sort of question. This is what I got back:

On the World War II Elco 80-foot Patrol Torpedo (PT) boat, the six external mufflers mounted diagonally on the stern transom are approximately 14 to 15 inches in diameter and roughly 3.5 to 4 feet in length. Each of the boat's three massive 1,500-horsepower Packard V-12 marine engines required two of these distinct, barrel-shaped "wet type" mufflers (one for the port exhaust bank and one for the starboard exhaust bank of each engine). Design and Dimensions: External Casing Diameter: ~14 to 15 inches. Length: between 42 to 48 inches. Internal Exhaust Pipe Size: The internal copper piping running through the transom and into the mufflers had a diameter of 8 inches, which matches the main exhaust manifold outlets of the Packard engines. The "Dimples": If you are looking at or building a scale model of an Elco boat, you will notice three distinct circumferential reinforcing ribs or "dimples" spaced along the main cylindrical body of each muffler casing.

My EeZeBilt Elco PT Boat is 1/48 scale - 20" long, and I made the mufflers 1" long, which looked in scale to me.

Hey there Steve:
This is a pretty cool article that may help a bit. 👍🏻

https://www.pt-boat.com/muffler/muffler.html