Flotation

[Peter H1956]

I see dinghies and other small boats have flotation added to their boats-does anyone add flotation to their small steamboats or does the weight of the power plant make this not practical?-

[barts]

This flotation is required by the US Coast Guard in commercially produced boats.

In general, traditional small craft with steam plants often don't have the interior volume to provide emergency flotation, which includes buoyancy for people, engines, etc. This is exacerbated if the boat burns firewood, which has far fewer BTU/cubic foot than liquid fuels. Remember that water weighs 62.4 lbs/cubic foot, so if your boiler, engine and pumps, etc. weigh 300 lbs you'll need to find 5 cubic feet of volume to fill with foam, plus more for some of the weight of the people, stuff, fuel, etc, not to mention the boat's hull if it doesn't float on its own. Sometimes one can use the space in the bow to provide flotation, but given the weight of the power plants we favor, it's not easy.

Of course, as the size of the boat increases, this problem becomes easier - there's more space, and the power plant is less of the total weight of the boat.

https://newboatbuilders.com/pages/flot2.html

- Bart

[Kelly Anderson]

I included foam floatation in the bow and stern of my first launch Reciproca, but then, with the Blackstaffe plant, all of the metal aboard only weighed around 275 lb. The hull and fuel are wood, and along with everything else aboard would float on their own. Even at that, with the limited volume at the ends of the hull, the foam took up 30+" of what would have otherwise been usable storage space on each end.

If you burn wood, and can tie it down, it would count as floatation. Otherwise, it will just float away.

Vividus on the other hand with her VTF boiler, easily has 1,000 lb. of metal aboard, and would require a good 17 cubic feet** of foam to compensate for the non-floating parts. That would be taking up a lot of room in the boat, so in case of serious damage or swamping, she will head straight for the bottom.

**But then again, a cube containing 17 cu. ft will measure only 31" on a side, so maybe it would be possible. Then I realize that my large boiler is only 22" in diameter, so maybe it isn't.

[Peter H1956]

I have been weighing everything as I build and I have about 300lbs of wood and 300lbs of stuff that will sink. The boat is a 16 ft double ender and not alot of spare room.
I was wondering if flotation is feasible or even necessary given my expected speeds .

[barts]

The only steamboat I've seen sinking (other than slowly at the dock due to leaks ) is one that ran into a submerged piling and stove in some delicate planking. They ran for the shore and waited until low tide to patch the hole; refloated at high tide and steamed full speed to the launch ramp. The hull was then used as a mold for a fiberglass copy....

I wear a self-inflating PFD; such things are available for boats, albeit at considerable expense and likely bespoke for the application.

You can of course tow one of those dingies w/ ample flotation on a stout line....

- Bart

[Mike Cole]

I pondered this once sat on in a steamboat over the middle of a very deep lake. My own steamboat Blue Buccaneer was build to include built in buoyancy tanks at either end.

[Peter H1956]

Thanks for the responses. This is my first boat (not counting my canoe) and I wanted to make sure I did not do something foolish. I will launch without flotation but I do have
an electric and manual bilge pump.

[barts]

This is my first boat (not counting my canoe) and I wanted to make sure I did not do something foolish.

Bringing along a friend in another boat is always a good plan on those initial outings...

Good luck!

- Bart

[Lopez Mike]

There has been at least one test of every electric and manual bilge pump available. The consensus was that all were wildly out performed by a frightened man with a five gallon bucket with water up to his knees. A decent fire extinguisher as well.

That said, they did not include a steam ejector. I don't have any idea about how much water they can move.

One small omission I just thought of. When calculating flotation, how do we rate the steam space in the boiler? Essentially the same as the same volume of air?

My boat was gazed upon by a U.S. Coast Guard Auxiliary volunteer who, after a moment's examination, opined that they didn't often inspect vessels that were already on fire.

Mike

[Kelly Anderson]

Ejectors are where it's at! Jet Pump Ejectors, Bronze, 6 gpm Liquid Suction At 5 Feet of Lift https://www.mcmaster.com/4977K11 .

"One small omission I just thought of. When calculating flotation, how do we rate the steam space in the boiler? Essentially the same as the same volume of air?"

When the boiler is submerged, any steam will condense and pull a vacuum, pulling water through the boiler checks, and filling it to the top.