A Smaller Steam Engine For A Smaller Boat

[apointofview]

Problem fixed

 

[apointofview]

I got the last planking done on the hull !! I pulled the boat off the forms, and it came off without any problems. I see why boats are built like this. It is really light and rigid at this point and I haven't put in the rest of the structure that is usually in these boats. I took the boat into my bath tub to see how it sits in the water and how much weight it will hold. To keep the water out I wrapped a trash bag around the wood and then marked the waterline on the plastic. It looks like it will take 10lbs to sink the hull low enough for the propeller and 14lbs is about as much as it will hold without takin on water with small waves. I used a bunch of canned goods to load up the hull and then measured the cans afterwards. The engine is one pound and the boiler is four so I have plenty of room for the rest of the gear. I still have to glue up all the seams because the forms limited access to the planks, they are basically tacked right now. Long way to go but progress is being made. It won't win any awards but it won't sink either !! ( well I shouldn't say that, the folks that built the titanic said something similar and that didn't go so well )

Hope this still interesting to some folks, it will be a little while before the engine makes another appearance in this thread on an engine forum. I can stop the updates till metal is beaten into submission if that would be more appropriate for this forum.
Pete

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[Herbiev]

Wow. It's really starting to take shape.

 

[Cogsy]

Looking really good. I vote for you to keep posting - it's interesting to watch and it's being powered by a home built engine so it fits the forum I think.

 

[Cymro77]

Keep it coming. I am enjoying since this is on my bucket list.
DW

 

[apointofview]

Ok great !
So here is what I did today. I boiled little strips of wood to form them into the ribs of the hull. I guess spruce isn't the wood of choice for bending but it's what I had on hand. It kinked and split a little here and there but with a little distance it doesn't show up and I don't think they are all that necessary for structural strength at this size of boat. They look neat though. Once they dry out I'll glue them in and possibly smooth out the little kinks with a bit of filler.....maybe. I guess after that I need to work out the fantail of boat.
Pete

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[Blogwitch]

Pete,

If you are wanting to bend spruce, just soak it a little while in household ammonia and you will be able to tie it in knots as it becomes so supple, but firms up when dried out.

John

 

[apointofview]

Really ? I might try that because these are a bit lumpy lookin. About how long does it need to soak ?

 

[Blogwitch]

I used a piece of block ended plastic pipe to soak mine in, less liquid used for the length required.

You can soak overnight, it shouldn't come to any harm, but I have had very good results with 1/4" x 1/8" strip after an hour, depending on the dilution, I used to make mine 2 parts water to 1 part ammonia, giving a rather strong mix. A few fellow modellers used a window cleaning product that contained ammonia, and they said they had good results, but the mix must have been very dilute.
They reckon it worked better with a heat gun as you are bending it, but I have never tried it, maybe they had to do it that way because of the low dilution.

Don't breathe in the fumes BTW, better to do it outside as well.


John

 

[apointofview]

I went and got some ammonia and put new strips in a Tupperware container, a pipe like you suggested would be the better way to go. I'll let it go overnight at least and then try it. You aren't kidding about the fumes, I was out in the garage and it was still bad. The wife would have killed me if I poured that inside like I was first gonna do !

 

[Cogsy]

I'm not sure what the difference is, but guys in my old aero club used 'cloudy ammonia' for the same thing. Rather than individual pieces it was used (I think sprayed over) fully constructed wings which were then slightly twisted and pinned until they dried to shape. From memory the carefully applied twist was to ensure the wing tip would stall before the root of the wing and make the flight characteristics inherently safer.

 

[apointofview]

I used to mess with r/c planes too and I had to soak a wing in the bathtub once to fix a warp I had accidentally built into it. 😳
Well I tried the ammonia and yep it did seem to make the wood softer, but I guess the wood I have is fairly low grade for bending. It still split easily and kinked here and there. So I swapped out the uglier of the ribs with the ammonia versions and went with the best of an ugly litter. All in all for a goof off scale boat it will be fine. So I have the ribs done and work on the stern of the boat is about done. I should have planed the stern when doing the rest of the boat because it's tough blending the add on pieces. Guess that's when planing ahead comes in handy.
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I got side tracked for a bit by a hunk of metal that the mail man brought me ! ( another non engine item )
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It's an 80% AR15 lower forging. A bit of carving and it's complete. It wasn't as tough as I expected but I don't have any trigger parts to prove I got it right either 😀. The directions for the cuts were about as lame as they come. The internet came to the rescue and provided me with all the dimensions I needed. Maybe the tolerances aren't at critical as I think if those directions work for some folks.
Pete

 

[a41capt]

80% lowers are quite fun, and you're right, the critical dimensions include the distance between the takedown pins and the deck height, as well as the magazine well and releases. Although I have seen folks Dick up the fire control group position! 🙄

For your next lower, try a 0% and test your set up and order of operation skills! The real test is the 0% upper...

Nice work as usual Pete! As a hobby gunsmith and machinist, I'm enjoying the hell outta your boat build.

John W.
Camp Verde, AZ

 

[dnalot]

Hi

Nice looking hull. And I should know, I owned and operated a boat building company for 30 years before retiring. I do some woodworking with veneers. It is dry as a bone, wrinkled and warped when I get it. To make the ultra thin wood workable without splitting I soak the part in Glycerin,water,alcohol mix.

3 parts water 1 part glycerin 1 part alcohol. With softer woods I add 1/4 part yellow glue. For thicker material, if the part is to be bent a considerable amount, after soaking place part in hot box to steam heat the part before forming. For small parts like your ribs a heat gun will work.

White Oak (not red) bends well but Ash is better.

Mark T

 

[apointofview]

John W - Thanks !! You peaked my curiosity and I looked up milling 0 uppers and a 0 lowers. Thats a good bit more work !! Someday maybe but not for now I'm not sure I have the tooling and skills to get it done. It would be really cool to pull something like that off.

Mark T - Thanks that's really great of you to say !! I Looked at a lot of hulls on the internet to end up where I am at. I hope it floats well !

So I am ordering a prop made by Raboesch as John suggested. Looks like I need a 75mm dia prop per the engine drawings and what will fit. This is the one that sounds right, the 177-26 A - Type prop.
http://www.loyalhannadockyard.com/PROPS.htm
Any advise ?

I want the prop so I can figure out what kind of drive shaft I have to drill for which helps set the engine location.

Thanks
Pete

 

[Blogwitch]

Hi Pete,

That prop should be OK as if needed (engine runs too fast) the blades can be bent to a more coarse pitch.

They do actually make designated steam props but I think they are all too large for your model and they cost a lot more.


John

 

[apointofview]

Ok good now if I can get one of the few American suppliers to answer my calls I will get one one the way.

I drilled the hole for the prop shaft which will be 3/16" riding in a snuffing tube that is 1/4". The problem that has come up is the shaft sits higher than the engine where it enters the hull. I know I could raise up the engine to align the shaft, but I have to keep everything as low as possible to keep the center of gravity low. The big heavy copper boiler sits high enough to make the boat a bit tippy. I may have to put lead in the belly or add to the bottom of the keel with lead to make the boat more stable. So it looks like a driveshaft with a couple of u joints is going to be needed. I could cheat and use a spare shaft I have for my tmaxx truck, but it's plastic and I didn't make it. Brass would be pretty, I would use the pins and c clips from the tmaxx and just replace the plastic with brass. I don't need it to be able to collapse so simple stainless shafts between the joints will work.
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You can see how high off the belly the engine would have to be raised

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This is the amount of miss alignment I have. The brass is the snuffing tube and a 3/16 shaft will ride in it.

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This is the general idea of what I need to do. My shaft will be a bit shorter just to shift the engine aft

Pete

 

[Ghosty]

Pete,
Use a couple of engine bearers to raise the engine to be inline with the prop shaft, will also give more strength to the hull for mounting the engine to.

Cheers
Andrew

 

[apointofview]

Oh and just a silly 80% AR update - everything fits !!! No warranty work needed. 😀
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[apointofview]

Andrew, that would be the better way except I want to keep the engine weight as low in the hull as possible. The boat seems tippy in the test floats because of the weight of the boiler. Since I went the vertical boiler route it puts a lot of weight high up on the boat. If I had gone the horizontal boiler way raising the engine would be the way to go.
Pete