Building a Steam Launch

[fredrosse]

Allternately: I built my 20 foot sharpie boat in just 12 weeks, while holding down a full time day job. It is made very heavy duty with 5/8 and 1/2 BS1088 marine plywood, 1-1/2 x 3 Douglas Fir frames, 16 inches on centers. It is epoxied inside and out with 10 oz cloth, with double the cloth on the chines. The bare hull was completed just 5 days before the last steamboat meet of the year, but I managed to install the engine, boiler, feed tanks, pumps, paddle shafts and paddlewheels, along with all of the connecting piping, in time for the steamboat meet. While not a traditional fantail, the boat has performed well these last 5 years, and now I usually choose steaming to woodworking, although it is a never ending process in perfecting the hull/decks/seats, etc . Cost of just building the hull is about $2,000 US it weighs around 1,050 pounds. I bought a used boat trailer from the local boat supply house for $650, and modified it, needed bunks and a new heavy duty axle/wheels.

[ezgo394]

@lighthousekeeper: I'm excited to hear you got yours completed in that time frame. I'll definitely check out that forum.

@fredrosse: 3 months is pretty spectacular. I assume the lessened build time is due to your usage of marine plywood vs strip planking? I had considered using marine plywood, but I'm worried about delamination of the layers when exposed to water (I know plywood can withstand water fairly well for a period of time), even if you glass it. Regardless, it's a nice looking, simple design. What kind of engine did you choose for it?

I've just received 'The Steam Launch' (autographed by the Author as well!) and 'Steamboats and Modern Steam Launches', used off of Amazon and both of them were in pristine condition. I'm already learning a lot from these two books.

I'm still deciding what design to go with, a 20' Cambrian or a 28' Corn Bunting (both from Selway-Fisher). My train of logic for the 20' is that the smaller size will be easier for me to build, and I can fit a 5-7hp engine with ease (thinking about the Reliable Steam Engine Co. 5hp Compound or the 7hp Triple. If anyone has experience with Reliable Steam, I'm interested in hearing what you think) and could pull the boat and trailer behind my Jeep. If I went with a 28', I could easily convert it into a closed cabin cruiser in later time. The only downside would be the large size (but I'm designing my shop on the assumption that I go with the 28'). Of course, I have plenty of time to decide, so it's not a big rush. I've also become somewhat enamored with the idea of a side paddle wheeler, so I'm still looking into that.

Thanks for all the replies!

[fredrosse]

"The lessened build time is due to your usage of marine plywood vs strip planking? I had considered using marine plywood, but I'm worried about delamination of the layers when exposed to water (I know plywood can withstand water fairly well for a period of time), even if you glass it."

Very true, plywood on frames will consume far less building time than strip planking. As to delamination of the layers, there is far less problems with marine grade (BS 1088) plywood than with strip planking methods. Both build methods use large surface layers with lamination/glue, however the BS1088 plywood does not delaminate, whereas strip planking has often been found to delaminate where there is water intrusion. Even with fiberglass/epoxy encapsulation, water is never completely eliminated. In my opinion both build methods should use fiberglass/epoxy outer covering, although it is optional with marine grade plywood. The main advantage of strip planking is obtaining a more ideal hull form, true to the shapes of the traditional hulls of a century ago. However a multi-chine plywood hull can very nearly approach the same traditional hull forms.

A quote from the Selway Fisher Boatbuilding Website: "For those steam enthusiast who want an elegant 22’ steam launch of Edwardian profile but who do not want to spend the time and additional cost of producing a strip planked hull, we have designed Ruby......" Selway Fisher has several designs for both strip planked hulls as well as plywood chine type hulls of the traditional steam launch forms.

The engine for the Margaret S. is modeled after the traditional American Walking Beam Engine, used throughout the eastern US for nearly a century. I like to see the machinery rocking and rolling at 60 RPM, much slower, and with much more "eye candy" than a typical vertical inverted engine running at several hundred RPM. On this forum there is discussion about this engine under "American Walking Beam Engine".

[malcolmd]

Ethan, go for it... sounds like a good project - I am trying something similar.... see Befur's Blog

Malcolm

[Lopez Mike]

I've not seem plywood 'delaminate' in many a year. Maybe some really cheap stuff from a box store but not in my experience. You could probably build a boat from OSB if you were willing to seal it with resin and fair the rough surface. (Awful thought)

I just did some repairs to a plywood bulkhead in my 1971 sailboat. Water had leaked in over years and years but the failure was due to rot, not failure of the laminations.

Sam Devlin has been making quality stitch and glue boats for years with zero failureshttp://www.devlinboat.com.

Just use decent plywood and epoxy resins.

There is the problem of being limited to simple curves. Double chine rather than single chine designs can help a bit with that.

[ezgo394]

@malcolmd: It's looking good! I look forward to seeing the finished boat!

@fredrosse: Interesting. I never thought that would happen. No matter what I go with, I will glass the outside and the inside. I've started to think that maybe I could start with a plywood boat, sell it, and then do a strip plank hull, as I do want to harken back to the olden days.
Yes, I did look that up. It's a nice looking engine (and boiler for that matter)!

@Lopez Mike: As said above, I didn't really expect that. But fair enough, I'm still looking into the matter and might do a plywood boat first.


I've been looking at boilers and boiler design and I've got two questions:
1) Does anyone have experience with a Horizontal Firetube boiler (gunboat style)? I've heard that they are heavier, but I think that aesthetically it looks better as a whole.
2) I've read that there have been no issues or major incidents with boilers in steam launches, but there is a little voice in my head that's becoming impossible to work with, telling me I'm gonna blow myself up. So, realistically, is there a safest boiler design? Also, will having a high rated pressure (ie 600psi vs 300psi) make it safer for those involved?

[DetroiTug]

Quote: "is there a safest boiler"

Yes, the one that is evaluated and operated by an informed conscientious person.

Steam is as safe as it is handled. Do things properly like using proper materials, proper build techniques, safe operating practices , you won't have any problems. Start cutting corners using improper materials, improper weld joints and piping, running the boiler dry etc, and then you're just asking for it.

To my knowledge there hasn't been a death by a boiler accident involving a steam boat since around 1912.

Quote: "Also, will having a high rated pressure (ie 600psi vs 300psi)make it safer for those involved?"

Fred will probably correct me here and that's ok. As I understand it, Working pressure of a boiler is generally suggested by the boilermaker. However if one researches the components used on our small boilers, the actual working pressure of those components is much higher in the 1000 - 3000 psi range.

1000 or 3000 psi is irrelevant when we are safetied at 150 psi. There is considerable threshold above the blow off setting. So each is as safe as the other.

-Ron

[Lopez Mike]

Unless you are an experienced and licensed (read: passed a specific test) boiler or at least pipeline welder, do NOT weld up your own boiler. There are all sorts of innocent looking mistakes you can make that have proven catastrophic in the past.

You can save a lot of money by cutting the steel following the instructions of your welder. In other words, consult with the welder before you do more than doodle on paper. There's a lot to it.

I'm not just being an old fuddy duddy. I wouldn't be so emphatic if I didn't care.

Yes, locomotive and scotch horizontal fire tube boilers have a long history of good service. They can eat up a lot of boat space though.

[fredrosse]

Gunboat boilers work well, are relatively compact, and achieve a low center of gravity, all good points. A better alternative in my opinion is a dry back scotch boiler, much easier to fabricate, similar to Mr. Weaver's project.

As to welding, " other words, consult with the welder before you do more than doodle on paper" .... I would recommend weld designs be developed by weld designers, not necessarily a welder. An experienced welder gets his experience from performing welds that have been detailed on the plans he is following, but that is not to say that the welder knows anything of weld stress considerations, etc. You need a good, qualified welder to make good welds, but that valuable skill says nothing of the welder's capability to design and size welds according to stress criteria.

As to operating pressures for a steam launch, any pressure from 15 PSIG to 4500 PSIG could be used, with safety. As Ron states, proper design and proper operation determines safety, it is not a function of operating pressure. However to move very far from the norms of our hobby, typically 100 to 150 PSIG, is to invite complications which will probably interfere with happy steamboating. For example, Steam rated valves (marked SWP) are common for 125 or 150 PSIG service, finding valves for higher pressures is 20x more difficult.

According to the ASME Boiler & Pressure Vessel Code, Copper alloys for any part of a boiler are prohibited beyond 406F, corresponding to 250 PSIG saturated steam pressure. You are not allowed to use copper alloy (Brass or Bronze or Copper) for valves, for sight glass, for try cocks, etc. I know Stanley Steam boilers, using copper firetubes, were run well above this current limit, but that violates the current boiler codes, and cannot be recommended here.

So if you want to build a 600 PSIG steam plant, you will probably spend far more on design and materials procurement than would be considered prudent. Having said that, the Whitecliffs project used 600 PSIG steam, and achieved probably the best efficiency for small reciprocating plant service that I have ever found in the last several decades.

[DetroiTug]

Quote: " finding valves for higher pressures is 20x more difficult."

And I found out exponentially more expensive. When I put my car together everyone told me I should run around 400 psi, so I figured the boiler can surely handle it and I can probably get a relief valve from McMaster-Carr. Up to 250 psi for a Kunkle is around $180. They quoted a 1/2" relief valve set for 400psi at $1400. I went with the 250 psi. I noticed riding on other small steam cars that they are generally under 200 psi anyway while running. It's not what the boiler can ultimately make, it's what it can generate under load that is important. They could be using 250 as well.

-Ron