Attaching engine to stringers

[johnp]

What type of fasteners do I need to use and how do I attach the engine boiler and bearings for props shaft?

[farmerden]

my boat has 5/8 lag bolts with machine thread on top [I know there's a correct name for this but I forget!] This arrangement allows one to shim for proper alignment.Don't forget to secure the boiler as well Have a look at this video and figure the forces at work here trying to break the stack off and toss the boiler overboard!! Den
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[Chris W]

The name you are looking for is hanger bolts. Not the easiest thing to find but they are out there. I have had to make special ones when the right configuration wasn't available.

[Lopez Mike]

I just looked up Stainless Hanger Screws and Bronze Hanger Screws on Google and Amazon and got several good looking hits.

As you probably have figured out, you temporarily jam two nuts against each other to screw the hanger screw into the wood.

My motor mounts in my sailboat (four hundred pound engine) are held down with 3/8" hanger screws and the boat has been in conditions where it was all I could do to hang on for eight to twelve hours at a time. Twenty years now and the engine is still in there the last time I looked.

Mike

[artemis]

My motor mounts in my sailboat (four hundred pound engine) are held down with 3/8" hanger screws and the boat has been in conditions where it was all I could do to hang on for eight to twelve hours at a time. Twenty years now and the engine is still in there the last time I looked.

Mike

And since Mike lives in the San Juan Islands he should know as sailboaters there spend most of their time motoring from one place to another.

[Lopez Mike]

Sad but true.

The violent motion, however, was off of the Baja coast. I had H.F. fax weather maps and I had gotten all full of myself and thought I was a weather expert. The rest of the Southbound boats stayed in Turtle bay listening to alarming forecasts. I, oh so self confident in my readings of my charts, took off. I got my nose rubbed in it well and truly. At one point my mush ended up stuck to the cabin overhead. Sigh.

Where were we. Oh, yes. Hanger screws are a good thing.

Mike

[farmerden]

Hanger bolts -That's the name I was looking for! While we're on the subject,When installing Hanger Bolts into a wood stringer that is fully encapsulated by fibreglass ,how do we seal the bolt to stop water from seeping into the wood and rotting? Or would it be wiser to place the bolt in resin before it hardens? Or am I just making a mountain out of a molehill? Den

[Lopez Mike]

I've never had any problem with rot but if I was worried, I'd smear the thing with goop of some sort before screwing it in. Silicon caulk would be good enough. With a hole bored to the root diameter of the hanger screw (bolt) there isn't much of a way for water to get in there.

Mike

[artemis]

I've never had any problem with rot but if I was worried, I'd smear the thing with goop of some sort before screwing it in. Silicon caulk would be good enough. With a hole bored to the root diameter of the hanger screw (bolt) there isn't much of a way for water to get in there.

Mike

Gosh Mike, let me know when your hull has become a pile of dry rot encapsulated in the shell of fiberglass - I'll take it and the machinery "in situ" AND haul it away at NO COST. Wood chip "plywood" is supposedly sealed, but if you use it on a bathroom floor and screw into it before you lay any tile or sheet goods I guarantee you'll replace it within 7 years (ex contractor speaking). Either drive the screw/bolt into the wood before the resin sets or drill a proper pilot hole and fill the hole with a good quality marine sealant like "Boat Life" or other polysulphide listed for use below the water.

[Lopez Mike]

Yeah, that stuff is really something. I've seen people actually fall through the floor in trailers. But there is a world of difference between that grunge and a solid timber. I think polysulfides are overkill for this sort of installation. You might actually want to get it out some day (grin).

Mike