Through Transom Bolts??

[AugustMoose87]

Finally got my outboard all fixed up, and I'm getting ready to install it. I was originally planning on using aluminum bolts, since the bracket on the outboard is aluminum, and that was there is no change of galvanic corrosion... But it seems like SS is used as much or more. Is this namely due to higher strength??

I know in an ideal world I'd use SS, but the bracket is already pretty badly corroded, so i don't want to add to the problem...

 

[Frank Acampora]

Re: Through Transom Bolts??

Correct: Aluminum bolts just don't have the strength for the necessary safety margin. Just butter the whole stainless bolt generously with RTV silicone to insulate from galvanic current. Of course, if you want to spend 50 bucks a bolt, you could always get titanium LOL.

 

[robert graham]

Re: Through Transom Bolts??

Stainless is the industry standard for transom bolts due to strength and corrosion resistance. My aluminum boat has Stainless transom bolts and there's no corrosion in that area. Aluminum bolts could fatigue and possibly break. Good Luck!

 

[ajgraz]

Re: Through Transom Bolts??

Can you even get aluminum hardware in that kind of size?

Another vote for stainless, with a nice big gob of 3M 5200 to seal the transom holes.

 

[5150abf]

Re: Through Transom Bolts??

Also on the iside where it meets the transom wood use some really big washers to help spread the load and prevent the bolts from pulling through.

I have stainless on mine and it is mounted to a raw aluminuim CMC tilt trim and haven't had and problems with a reaction, but yes, if you like your engine use stainless.

 

[Chris1956]

Re: Through Transom Bolts??

August, Your posting shows Iowa. Are you using the boat in saltwater? If not, galvanic corrosion is not an issue.

In freshwater, you may use galvanized steel bolts if you like.