Engine mounting bolts - use stainless, or no?

[dLj]

My vote is stainless. I usually prefer 316 on my boat. But if you're concerned for strength, you might want to look into these:

https://www.mcmaster.com/#standard-hex-head-screws/=1c13eov

Although you are talking $3.40 a bolt for M10 bolts.. Not sure you need them. Alloy 20 is nice, but I don't know where you'd get metric threaded bolts. Unless you want to machine them - or get them machined. You can get Alloy 20 also from McMaster...

dj

 

[Gene Neill]

Guys,

I get intimate with a lot of boats. The vast majority of sailboat builders use SS. In fact I can't think of one who does not use SS for affixing the mounts to the boat..... The majority of builders simply run lag screws into glass encapsulated wood stringers/mount beds.

Just a few builders who use SS bolts for mounting the engines to the stringers.......

Morris
Gunboat
Hunter
Marlow/Hunter
Catalina
Cape Dory
Bristol
Beneteau
Jenneau
Hanse
C&C
Able
Saga Yachts
Southern Cross
Sydney 38
Tartan
Leopard
Lyman-Morse
Cal
Lagoon
CS Yachts
Ericson
J-Boat
O'day
Pearson
Pacific Seacraft
etc.
etc.
etc...

Well, now. That certainly puts my original question to bed. Just in time, too; it's Sunday evening and I wanted to click the "buy" button before morning. My mind (and my McMaster order) has been changed. I'm going with stainless.

Thank you, Maine, and thanks to everyone else who posted. There are some amazingly intelligent and educated people here. I'm humbled and grateful for the help.

 

[jibes138]

Stop that order. There is stainless and then there is stainless. I highly recommend you consider Nitronic 60. It is comparable to 304 and 316 corrosion resistance but with twice the strength and anti galling properties. https://www.hpalloy.com/Alloys/descriptions/NITRONIC60.aspx