Zinc Bolts...

Hey guys Im new here and been looking over the site for a week now. I found the site while i was looking up picks of boats. I bought a 16' PolarKraft 42" wide. It has a 25 Hp Mariner on it. Picked it up last week. On the maiden voyage we took alot of water on due to the transome being shot. I have started to rebuild it with all the great info on here, But alas I have a question. I know Steel bolts will corrode the aluminum but what about Zink? Anybody tried it? Any knowen problems? I found the Zink Hardware much cheaper than the SS stuff. And I could not find 3M 5200. So i bought a tube of 100% silicone by liquid nail. Will it work? I have not put things together yet so I can "undo" if I have to. Any Tips will be appreciated. Thanks.

The Zinc bolts you are referring to are zinc coated steel. The zinc is a somewhat rust resistant coating but they will rust and are probably unsuitable for a marine enviroment. Also, stainless bolts will cause aluminum touching them to corrode so they probably aren't the best for anything touching the hull.

Stainless is the way to go - I have had some in the boat since 1972 and so far no reaction with the hull


DO NOT USE ZINC - you will have big problems with galvanic reaction and rust

SS is the way to go and remember no pressure treated wood.

Use stainless only in your transom.

Ok Guys, thanks for the info. Looks like I will be taking the Zinc stuff back tomorrow, and picking up some Stainless Steel hardware. I used standard 3/4" Plywood,built up to 1-1/4"(had to plain off 1/4"), secured together, and coated with polyurathane I had in the garage. I know I should have used spar urathane, But the wife is into me about the cost of this Boat Thing lol. I figure it should last a few years with a little maintanace. The original transom was still in place from the factory and the boat was built in 73'.

Here is a nice explanation of Galvanic corrosion in boats:

https://www.skippersschool.com.au/docs/boat%20tips-04.pdf

In the text he mentions the "Galvanic Series". It is a useful tool for selecting materials to be used in your boat building projects. You can find a version with practical application to boat building here:

https://www.corrosionist.com/Galvanic_Series_of_Metal_in_Seawater.htm