Beefing up a transom

[lordy]

Anyone know a good spot/person to beef up a fibreglass transom? It is already rated to 85hp but we would like to put a second hand 90hp on it. There are plenty of 90hps about second hand and beefing it up seems easier than waiting for one of the 85hps to become available. We could probably strengthen it ourselves but then there are probably legal problems doing it yourself.

[NQCairns]

Hi lordy, there may be other options depending on how old your motor is, if it is old enough to be power rated at the flywheel then you would probably get the same performance out of a more modern 70 that is rated at the prop. Regardless 5 hp is not going to make a dot of difference to your transom if the transom is in good condition and you have no complaints about the 85 on it, what will be important is weight more-so than than the HP you are thinking of fitting. Nq

[afro]

Lordy,
I agree with NQ, I dont think the extra 5 hp should make much diference. You should look to see wether you will be able to get insurance as the motor is over the max. allowable. I know with alloy boats the max hp is not rated on what power the transom can take, rather the weight and the safety of the boat at speed.
Cheers Justin.

[lordy]

The boat in question is a 1978 model (hull is in great nick), so its may be 85 rated on the flywheel (I'm not sure when they changed). I'd have no hesitation putting a modern 85hp on it (the compliance plate is fine with that). It looks strong enough to take a 115, so a 90 should be fine in terms of transom strength.

We'd like a 90 because we have added a lot of weight to boat in the way of decks and live wells etc. The weights of the 70s and 90s seem to be the same anyway (and the costs are similar) so might as well get the 90.

Its just a matter of insurance and to do that we would need a new compliance plate (I suspect). We might not even need to beef it up to get one, I just don't know where to look. I might call Haines.

[aussiebasser]

Oh Dear Lordy,
You mentioned the scarey word "Insurance!" You'll probably need to have the work professionally done by a qualified person who will then be able to refer you to the relevant marine authorities who will inspect the hull, and may issue an ammendment to allow you to approach an insurance company who may cover the boat, but in the fine print you will probably find that in the event of a claim they may be able to wipe you.
The first people I'd be talking to is the Insurance company you intend to use, and get their answer in writing. You may be wasting a whole heap of money for nothing otherwise.

[lordy]

Thanks Basser. I might just do that. If that is case I be looking for an 85hp....

[Jeremy]

Actually, I went through a similar experience with my Stessl boat recently. It was rated to a 35 and I wanted to put a 40 on it. I just took it down to Stessl (after a quick chat) and he made me a new compliance plate which now rates it to 40 hp. It cost me $100, but it solved my problems. I was in touch with the insurance company (Suncorp) throughout and gave them a copy of the new compliance plate. No problems.

Jeremy

[lordy]

Spoke with Haines today and they didn't sound as if they thought it would be legal. Either that or they weren't interested in helping. So it looks like we will have to stick to 85hp or under.

[Cloud_9]

lordy the only deference between 85 and 90 is in the carby.
best bet try and get a yami 85and a good out board mechanic to pep up the 85 to a 90 under the hood.
just like doin a chip in ya commodore. accept you do jets or carby. but i have merc 90 and mate of mine got a 85 yami there was'nt much in it at all performance bewteen the 2, a couple Kmh.or even a late model 75 merc they all go pretty hard compared to the old 85's

[Cloud_9]

Just a PS to check transom get wooden malet or wooden hammer handle and tap around the transom. if it sounds hard its fine, if it sounds dull it's got rot in it, you can tell difference just have a tap around, you don't have to hit it hard just tap.

[lordy]

Just a PS #to check transom get wooden malet or wooden hammer handle #and tap around the transom. if it sounds hard its fine, if it sounds dull it's got rot in it, you can tell difference just have a tap around, you don't have to hit it hard just tap.


Transom is rock solid, we have the front deck built, the rear deck in ready to be fibreglassed in. I wish I had a digital so I could do a project boat shoot like some of the others around here have.

As regards the motor tweaking its certainly a possibility.