Building a Steam Launch

[Lopez Mike]

I concur with what Fred just said about welders. My assumption was that one would use an existing design with properly laid out joints and competent analysis but that the welder would advise you about the gaps and bevels and assembly sequences that he/she needs to do a proper job.

Time and time again we see well meaning people come to this hobby with notions that they are going to revolutionize efficiencies to improve the perfomance of the power plant. It just isn't going to happen. This was beaten to death over a hundred years ago. This is extremely mature technology. In these power plants the heat losses far surpass any marginal gains from technical solutions. Mice got to eat a lot. Big animals not so much.

Try to look to the total experience not just the power plant. Steaming with a boat that is silent and trouble free is a special thing. My boat is far from a paragon of great design and execution but I took Bart and Barbie out for a few hours last week and the most remarkable thing that happened was that nothing happened. I poked wood in the firebox and we went boating. Period. Looked at birds and the scenery. Touched a hidden rock (!). Looked at houses built by very rich but absent people. Dodged kelp beds while flowing up and over Pacific swells. But no fussing with the engine or boiler.

Execution errors are easy to fix. And once fixed they say fixed. Tighten the packing gland or what ever. Design flaws are discouraging. Unless you revel in adversity, stay traditional.

[ezgo394]

I've been looking some more and have read that a water tube is 'safest' due to the lesser amounts of water held in the boiler compared to a fire tube. I think I might go for a 3 drum water tube boiler. I

To make this clear, I did say earlier that I was thinking of welding my own boiler, but after reading up, I will not weld or design the boiler. I will get a certified boiler engineer and welder. I don't mind building everything else myself, but I'll leave the pressure vessels to professionals.

Concerning pressures, I see your point. I think I'll get it designed at/around 300psi (I'm not expecting to get above 200psi).

@LopezMike: I'm not looking to revolutionize anything. I'm coming into this with the expectation of owning and playing with some steam toys. I'm just wanting to research everything and find the best methods and designs for what I would be comfortable with.
I'm also doing this, as you say, for the whole experience. But before I get there, I need the boat, and unless a good used boat pops up, I have some planning to do .

[Lopez Mike]

Yeah, a boat is probably one of the biggest single issues for me. I'm a machine guy so I haven't had much to fuss over in the power plant but my hull is, shall we say, 'esthetically challenged'. And not built so well either!

I'm looking at the Sam Devlin system. He's not the only one doing it but he's been at it for longer than almost anyone and he has a great book out with very practical advise.

There is much to be said for either fire tube or water tube. The water tube ones look all complicated to me but I can't say that they perform that much different from each other. The fire tube designs have more reserve capacity and react more slowly to load and firing variations.

That can be good and bad. Good when you are lazy like me and forget to stuff some wood in. Bad when you are inattentive like me and arrive at the dock with a firebox full of fuel.

[PeteThePen1]

Hi Ethan

You have certainly done the right thing to join the Forum and ask lots of questions. The guys here have all the knowledge you might ever need, or will point you in the right direction to find it. However, I don't think anybody has asked you what I think might be two important questions:

1. Do you want to go steamboating or is creating your own boat more important? If you want to go steaming, then buy a second hand boat, get some training in how to use it and have fun. Don't forget you don't have to limit your search for second hand boats to the US. The UK is suffering/enjoying a huge depression in steam launch prices just now due to the economic conditions here. Shipping a boat across the Atlantic on a trailer is not cheap but not outrageous. If you do that make sure that the trailer you buy will be legal in your state. I didn't even think of that issue and it cost me lots to get it sorted.

2. Do you have a 'significant other', and does s/he have any interest in this new hobby? If the answer is yes and no, and you wish them to remain significant, don't expect to spend all your spare time in the workshop. A boat is just a boat, but a loved one is somebody special and too precious to lose.

So there you are, nothing 'technical' at all.

Regards

Pete

[farmerden]

I have a boiler that is exactly what my engine requires. It will run all day at 100psi to 120 psi but if I add water or blow the whistle the pressure drops. Riding around in other boats this summer ,I noticed bigger boilers which much more tolerant in running. The water level was far more constant, the pressure was constant, the engineer could solialize with the passengers!! My daughter steers my boat and I run the engine but we are both busy at our stations. So I would have to say that if I were to build a another boat I would lean towards a bigger boiler [and yes a bigger whistle!] but it's the constant water level pressure that I really would like. Any comments? Den

[Lopez Mike]

Get some of those other loafers riding alone to tend the boiler and engine for you. They're too busy rubber necking at your daughter!

[ezgo394]

@LopezMike: I definitely understand. I'm a machine guy too and the main reason I'm wanting to build is so I can mess with the steam toys and at the same time, have fun on the water.

@PeteThePen1: I want to do both. I'd like to operate something that I have built entirely from scratch, something that I can be proud of and want to show off. But, of course, I want a steam boat so that I can experience the operation of it, as well as explore. As I've said before, I am not objecting to a used boat. If one pops up that I like, I'll take it.
No, I do not have a girlfriend or an S/O that will drag me down (although it'd be nice ), so no worries there.

@farmerden: By no means am I an expert, but from what I have read and understand, if you are losing much pressure from something as simple as the whistle, right off the bat, you have a small boiler. It would also be important to know what kind of boiler you have. If you have a horizontal or vertical fire tube, then you should have the water capacity and the steam capacity for variations in demand. If it's a water tube, then you have to account for the lesser amounts of water in the boiler and design accordingly... At least, that's how I see it. Concerning a new boat, as I am from Texas, remember; bigger is always better (within reason).

[farmerden]

Yes it is a water tube and it only holds about 5 gal. And being a Canadian well we just have to have a bigger boiler than Texas!