Penbwl a Welsh tadpole

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Tony Bird

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Hi,

It is some time since I posted anything in HMEM, for the last couple of months I have been making a copy of a model steam powered boat described in the August 1933 edition of Popular Mechanics. I have to say that it isn't the prettiest boat that I have built but it does have a certain ugly charm. Known as Polly Wog which I believe is American slang for tadpole the designer isn't credited in PM. On the net I found a 1939 catalogue of a company name Boucher that was marketing both a finished boat and a kit to build a Polly Wog. I wonder if they got the design from PM? It would be interesting to know.

The build started because a member of the Mamod Forum to which I belong to, posted the plans and text for Polly Wog which he had found re-published in a Live Steam magazine.

I was looking for something different to make and Polly Wog is different! A steam outboard motor, a boiler consisting of three tubes joined at each of their ends and a twin rudder in front of the propeller.

Some of the materials suggested were a little bit of a problem to obtain in South Wales: Orange boxes for the hull bottom, aluminium stovepipe for the deck, bevelled gears from a radio tuning condencer for the right angle drive of the engine and a slip tee for the gear box housing being particulary difficult to sourse.

The boiler is heated using Sterno and produces enough heat to power the engine easily. It has been tested in a tank and seems to work well. A safety valve has been fitted instead of just a filling plug as suggested. Rudder only R/C is fitted. Unfortunately our local lake is weed bound until the winter kicks in when it dies back, so it will be some time before it can be tested.

A direct translation of Penbwl, pronounced Pen as in ink and Bull as in cow, is flat head and is used in Welsh for Tadpole. Why Tadpole as well? If you have visited Wales virtually everything is in both English and Welsh. It seemed a shame not to do the same also there were enough letters on the sheet of transfers to do it. The other side has Polly Wog on it just in case she goes to the States, I would hate a language problem.

I did take some photographs of the construct techniques if anyone is interested, which I could post retrospectively.

Regards Tony.

011 PW Finished Penbwl Tadpole LR.jpg


010 PW Finished Penbwl Tadpole LR.jpg
 

Brian Rupnow

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Very nice!!! I see you are using twin wobblers for a motor drive. a lot of folks on here would appreciate plans for that engine.--Very nice and unique project.---Brian
 

dsquire

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Tony

I don't care if it is a Penbwl or a Tadpole, it still is a very nice boat. I can well imagine that you would have had a hard time finding Orange crates to use. My sister still has 2 of them from when we were kids. We used them as bedside tables when we were kids. I think that I would have a hard time if I were to try and use one to build a Tadpole.

We definitely would like to see some more photos and details on how you built the boat as well as the engine details. Perhaps you could re post the plans if it doesn't violate copy-rite or post a link to them.

Thanks for showing this to us.

Cheers :)

Don
 

Brian Rupnow

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DSquire--It must have been a Canadian thing. All the beds in the house I grew up in had orange crates stood on end as night tables beside the bed. My mother had sewn fancy slipcovers for them. they even came with a built in divider that acted as a shelf.---Brian
 

dsquire

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DSquire--It must have been a Canadian thing. All the beds in the house I grew up in had orange crates stood on end as night tables beside the bed. My mother had sewn fancy slipcovers for them. they even came with a built in divider that acted as a shelf.---Brian
Brian

It was the same in our house. Mother or Grandmother had made nice slip-covers for them. If I remember correctly mine had Cowboys and Indians on them.

Cheers :)

Don
 

Tony Bird

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Hi,

http://books.google.com/books?id=7OEDAAAAMBAJ&q=todpole#v=onepage&q=Polly% 20wog&f=false

Yes that is the original article from Popular Mechanics. My copy came from the October 1981 edition of Live Steam which is identical to the original article.

If anyone is thinking of making the boiler or engine it will need drawing out as there are anomalies in the dimentions. I will see if I can make sense of the sketches that I did and post them along with some constructional photograghs.

Regards Tony.
 

Tony Bird

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Hi,

Some photographs of the construction of Polly Wog's Hull. Steaming hull sides, bending hull bottom and finished hull.

Regards Tony.

012 PW Construction steaming hull LR.jpg


020 PW Construction Mk2 bending  hull base LR.jpg


018 PW Construction hull assembled LR.jpg
 

Tony Bird

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Hi,

A start was made on the engine. First a drawing was made based on information from the Polly Wog article. The engine was made using the suggested materials including copper cylinders!

Regards Tony.

Polly Wog Drawing 001 LR.jpg


001 Polly Wog cylinder LR.jpg


004 Polly Wog cylinder soldering finished LR.jpg


010 Polly Wog driilling ports in base plate LR.jpg


013 Polly Wog base plate finished  LR.jpg


015 Polly Wog to date LR.jpg


019 Polly Wog big end LR.jpg


026 Polly Wog big end LR.jpg


030 Polly Wog piston finished LR.jpg


032 Polly Wog pistons fitted LR.jpg


036 Polly Wog in steam LR.jpg
 

dsquire

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Tony

Very nice work there. I'm keeping an eye on it.

Cheers :)

Don
 

ProdEng

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An unusual and attractive project, thanks for sharing.
 

Tony Bird

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Hello again,

Still sorting photographs must use a better system! Propeller gear box assembly.

Propeller next if I can sort the photographs out.

Regards Tony.

011 PW Gear box to date LR.jpg


022 PW gear box cover fitted LR.jpg


025 PW Gear box gears fitted LR.jpg


027 PW Gear box so far LR.jpg
 

nemoc

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Tony, It looks pretty to me. Outstanding workmanship! You did a great job with the sheet metal. Thanks for the photos.

Craig
 

larry1

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Great work,I think that the boat looks great. larry
 

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