stringers (engine bearers)

[johnp]

what type of wood do i use and what size for a 2-3hp simple and 20sqft vft boiler.

[87gn@tahoe]

I may catch some flack for saying this, but here goes...

I would use some type of corrosion-resistant metal instead of wood. On my father's "George H. Sandin" He used Oak soaked in epoxy then glassed to the hull. Now, 25 years later, the wood has rotted and the boiler and engine are unstable. My father had to make some creative bracing, tying in the boiler to other structures in the boat to alleviate the problem..

Depends on how long you want it to last I guess.

[barts]

Note that oak, while strong, rots quite quickly.

I'd use vertical grain Douglas fir. Size depends on what your hull framing looks like
and what kind of span you're covering.

- Bart

[johnp]

6' long i think

[gondolier88]

Hi John,

Seasoned English Oak is absolutely fine, but MUST NOT be sheathed in any way- water will sit inside and rot it in no time at all. Treated with copius amounts of cuprinol and soaked in engine oil they will last years.

Not knowing your location, if you are in the US or Canada, as has been suggested a decent softwood, DF would be ok, but I would suggest Pitch Pine or Larch.

Greg

[barts]

If your engine has the typical small base, I'd make up a small steel mount that also acts as an oil pan. This would allow you to spread the load a bit (this also reduces loads on the wood due to rocking) , and prevents oil from leaking into the bilges. I'd make that steel unit pretty strong, as its stiffness will really help keep vibration down. This can also take care of inclining the engine at the correct angle to meet the prop shaft if needed. It should nest in between the engine bearers....

The distance between supports in the photo looks like 3 ft rather than 6... if so, my first inclination would be to use either select or vertical grain DF, about 2 x 4 nominal, laid flat across the existing floors. I'm on the West Coast; DF here is strong and dense in the better grades. I'd coat the places where the bearers rest on the floors with a suitable sealant to keep water from accumulating there and causing rot. I treat my boat with a very traditional wood preservative - a mixture of linseed oil, pine tar, turpentine and a splash of varnish so it dries properly. It also smells nice, but wear gloves when applying. This finish is much easier to repair than varnish.

I'd make sure to paint the bilges with some light colored epoxy paint after proper prep; this will make finding dropped items much easier.

- Bart

[johnp]

cut them around the floor stringers? it looks like they should be 2"x8" notched around the floor stringer and i would assume epoxied to the hull and the floors(stringers). or would i just drill through the stringers floors(stringers) and carrige bolt from the underside? i will have the boiler between 2 stringers and the engine between the another two. outside to outside od floors(stringers) is 5'.

[barts]

cut them around the floor stringers? it looks like they should be 2"x8" notched around the floor stringer and i would assume epoxied to the hull and the floors(stringers). or would i just drill through the stringers floors(stringers) and carrige bolt from the underside? i will have the boiler between 2 stringers and the engine between the another two. outside to outside od floors(stringers) is 5'.

Alright, that's further than it looks in the photo....

You don't want any wood sitting in the bilge water if you can avoid it . Do you know how much the boiler weighs?

- Bart

[johnp]

no, no, i'm not that far. i'm asking if that's how it should be done. or do i just glue and screw them to the floor stringers. this is my first steamboat. i've on;y everv seen them on the internet. boiler is 20 sqft vft 18" x 30"ish i guess 3-400 lbs

[DetroiTug]

I mounted a 4 cyl Gray Marine Sea Scout in a fiberglass hull a long time ago. For engine bearers, I used two white oak, full 2 X 6's about 8' long to distribute the load. It was a hull designed for an outboard with a sealed floor. I cut an engine space out of the floor, then fair'ed the bearers to the bottom, keeping them parallel and plum. Then I simply bedded them in life caulk and secured them with stainless lag bolts from the underside of the hull. Bolted right through the fiberglass. Worked great. As long as stainless or at least hot dip galvanized fasteners are used and everything is sealed it wont be a problem.

Learned the hard way boats designed for outboards don't set well with an inboard, had to add some ballast at the stern.

-Ron