SHETLAND OWNERS ASSOCIATION

We have a shetland 535 doing her up. It had a Mariner 40 2 stoke on it. But might have chance to but a Mercury 75 2 stoke electric start tilt and trim Long shaft.
Will this over power the boat would it be too heavy for the boat and is a long shaft not the best. Have to make a decission soon on this so if you have a min please can someone give me some advice. Never owned a shetland before and I want to get this right. Cheers Jack

Originally the max recommended power was 65hp. You could run into insurance problems if you exceed this. Also worth remembering that some of these boats are getting on for 50yrs old, you need to check how solid the transom is, they have been known to rot inside

I'm with Vreagh. Leaving aside the (important) insurance question, then physically the boat will support the weight. My own 535 has a Mariner 60 EFI four stroke and a Yamaha 4 horse four stroke hanging on the back. Given that generally two strokes are somewhat lighter than four strokes you should be OK, BUT only if the transom is sound. This is my second 535, both of them had serious internal degradation in the transoms, necessitating a complete transom rebuild. You may be OK, but signs to look for include:- find the biggest strongest guy you can and physically try to bend or flex the transom by hand; if an engine is attached use that as a lever. Obviously don't go crazy, but there should be no visible flexing. -Try tightening one of the existing engine mounting bolts. Again don't go mad but if a normal size spanner enables a bit of tightening is there inward movement (dishing) of the fibreglass around the bolt? -lastly, a clout with a soft face hammer should give a crisp knocking sound rather than a muffled soggy note .
If in doubt, a rebuild is needed. A good 75 horse engine will rapidly cause a bad transom t worsen quickly, even to the point of disaster.
Good luck!

Thanks for replying. I know what you mean about the transom. We came across this on the 535 . Have dug it out, replaced it with marine ply two pieces epoxied together and fibreglassed. Mixed more epoxy and hardener poured it all down into the transom bad parts.Then fb glassed the top of the new wood. Now going to cover 3/4 of the width of the transom with 1/4 inch or bit bigger aluminum checker plate. Opinion please, thanks again for your help. Jack