JawsOrca Posted September 16, 2014 Share Posted September 16, 2014 I ordered the bolts from the manufacture of the sterndrive to bolt the transom plate onto the hull and i'm surprised to see that they have sent A2 stainless bolts.. I at least expected A4 (316) considering they will be underwater... Am I wrong and A2 is OK to use underwater? Quote Link to comment Share on other sites More sharing options...
Hockham Admiral Posted September 16, 2014 Share Posted September 16, 2014 Alan, Hi. I've just read quite a few pages on this topic..They all agree it must be A4 because of the molybdenum (2-3%) that's added. Here's one you might like to peruse: http://www.canalworld.net/forums/index.php?showtopic=51126 1 Quote Link to comment Share on other sites More sharing options...
JawsOrca Posted September 16, 2014 Author Share Posted September 16, 2014 Thanks John (sorry .. I found that too.. It's the salt bit of the broads which I thinks complicates things.. although I had a big long chat with the chap about the boat being in brackish water although he still sent A2 so I'm hoping he knows more.. I think I'm going to send back though and get A4.. piece of mind.. 1 Quote Link to comment Share on other sites More sharing options...
JawsOrca Posted September 16, 2014 Author Share Posted September 16, 2014 I need to stop panicking (I need a holiday!)... They company replied stating that A2 is far less reactive than A4 and would be fine (as they have been since 1969!)... 1 Quote Link to comment Share on other sites More sharing options...
MBA Marine Posted September 16, 2014 Share Posted September 16, 2014 A4 is better, A2 will cause you no problems, apart from one, avoid A2 nuts as the have a habit of seizing on the threads especially nylocks, they fuse solid and even the likes of a m12 the bolt will sheer before the nut lets go! 2 Quote Link to comment Share on other sites More sharing options...
JawsOrca Posted September 16, 2014 Author Share Posted September 16, 2014 Brilliant, top tip.. thanks Mark.. appreciate that.. I must admit most of the nuts on this outdrive when we have tried to take it apart have done just that (I thought it was me!).. Quote Link to comment Share on other sites More sharing options...
mbird Posted September 17, 2014 Share Posted September 17, 2014 A4 is better, A2 will cause you no problems, apart from one, avoid A2 nuts as the have a habit of seizing on the threads especially nylocks, they fuse solid and even the likes of a m12 the bolt will sheer before the nut lets go! Hi Mark I know what you mean about stainless Nylocs. I detail structural steelwork for a living for the construction industry, and they prefer to use stainless self-locking nuts, which have a split crown rather than a nylon insert. One question for you though, I thought I had read that A2 bolts were more prone to cavity corrosion than A4. Has that been your experience too? Quote Link to comment Share on other sites More sharing options...
Guest Posted September 17, 2014 Share Posted September 17, 2014 A4 for me on boats, every time, especially when immersed. I rarely use A2 even at home now, because it also has a very frequent problem with welding itself up tight due to "reaction" when first being threaded together . Something that never happens with A4, or even mixing A4 nuts with A2 bolts or vice-versa. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.