The Steamboating Forum

Wow!!! I'm impressed!

The first time I ran this engine I detected a clunk from the crank, on checking I found the flywheel loose, I tapped the taper key home and thought that's that.

I ran it again having messed with a few other bits and there was still a clunk. Not the flywheel. When cold again I found a bit of clearance in both small ends. I carefully stripped the slide bars off this morning, and then removed the outside slide and pin and this is what I found.
Whoever built this thing did a fantastic job, the only thing here is that the bearing halves appear to be butting so will need to be trimmed. That gudgeon pin is only 5/16" dia so you can see how small all this is.

Wow. The level of detail is impressive indeed! Many would have just "called it in" or faked it. What a great quality model.

fredrosse wrote: ↑

Wed Apr 01, 2020 9:05 pm

The originally proposed hull, with a loaded displacement of 780 lbs (0.35 long tons, very close to 0.35 Metric tonne), can make 4 knots with propeller drive at 0.45 shaft horsepower (0.34 kW). Best arrangement is 500 RPM with a 12 x 12 propeller.

These are rough numbers, I would think +/- 20%, but still useful for this discussion.

Fred, having looked a lot closer at the drawings, I believe that 12" x 12" would be just about possible, but pushing things a bit (pun intended). 9" or perhaps even 10" would be much more practical, what does you calculator suggest as pitch for those sizes? These sizes might still require some minor modification to the stern and skeg.

A 10 inch dia. x 9 pitch propeller at 717 RPM would be ok, requiring 0.475 horsepower. With the original 0.45 horsepower the boat would make only 3.95 knots, no big difference. Probably best to use a steam engine at lower RPM, in the vicinity of 400-600 RPM. A toothed belt drive would easily do this.

10 x 10 propeller at 650 RPM
10 x 12 propeller at 535 RPM

I think I would probably choose the 10 x 12, with direct drive,running a small steam engine at 535 RPM

Engine, 1.5 inch bore & stroke, double acting single cylinder, 535 RPM, giving about 0.5 HP at a BMEP of 75 PSI, 140 psig main steam pressure.

Thanks Fred, that gives a little more to the equation. After confab with P.T.P. we are working on several scenarios. Meanwhile when I next run the little twin I will put the tach on it and see what revs it's happiest at. There is currently no counterbalance on the crank/flywheel and I want to experiment with adding a little to see how it fairs.

This is all at the expense of getting on with the bigger twin of course.

Talking of the little twin, today, under full lock-down conditions, that thing the executed the feline took hold, and I removed one of the valve-chest covers. This is what I found.
IT is a lovely piece of work throughout, worthy of a museum model.

I also, having to hand a Lovejoy coupling, bored and keyed it to the crank.
I'm not sure how far this is going to go but, 'tis fun none the less!

dampfspieler wrote: ↑

Sun Apr 05, 2020 8:18 pm

Hi Mike,

a friend runs a canoe with a 38 x 38 mm (square 1 1/2") single and a VFT-boiler like mine. The prop has a diameter of 220 mm and a unknown pitch - it comes from a 2 hp outborder.
He steamed it on the Moselle river.

Here is a video - https://youtu.be/3G_ukzzOCZg

--
Dietrich

Sorry Dietrich, somehow I missed your post. Roughly, what is the heating area of the VTF? I presume also the pitch on the prop is very course being from an outboard. It seems to push it along at a good speed.

A thought for today, if your outboard falls off, does it become an overboard?

Hi Mike,

... Roughly, what is the heating area of the VTF?

3.500 cm²

... I presume also the pitch on the prop is very course being from an outboard.

Ronny (the builder of the plant) had increased the pitch by hand so he is possible to run it with lower speed than the original for a reasonable speed of the canue.

Dietrich

dampfspieler wrote: ↑

Thu May 07, 2020 2:59 pm

Hi Mike,

... Roughly, what is the heating area of the VTF?

3.500 cm²

... I presume also the pitch on the prop is very course being from an outboard.

Ronny (the builder of the plant) had increased the pitch by hand so he is possible to run it with lower speed than the original for a reasonable speed of the canue.

Dietrich

Ahh great, understood! I too prefer to run at lower revs where possible, I think it is less strain on bearings etc.and the sound is often much better.

"Roughly, what is the heating area of the VTF?
3.500 cm²"

In typical English/USA practice, that is 3.77 square feet heating surface. Very close to the 5 square feet heating surface for the boiler used in the Steam Scanoe, which was made from a 15 ft long Coleman square stern canoe.

"A thought for today, if your outboard falls off, does it become an overboard?"

Under this circumstance, I think it becomes a "Far-Out Outboard"?

Cabin fever is setting in.