motor well / mount repair

[EvenKeel16]

Hi Guys,

this is my very first post! I've had my M26S '91 for a couple years now and have been reading on the forum quite a bit. my previous boat was a compac16. So big change. Anyway when i bought the my boat the PO had done a not so great repair where the motor mounts (honda 9.9). i knew it would just be a matter of time before i had to make a good repair. So it finally started to crack where PO repaired. just along the top not all the way down or anything. the fiber glass came off the top and i see plywood under but the plywood seems solid. questions

- Has anyone done a repair similar and can offer some advice?

- Does everyone just clamp on the motor or clamp and bolt thru?

- any other advice on this matter ?

second nagging problem -

- can some one send me a picture of their quick connect fittings for the Honda 9.9 from motor to gas tank?

other than that great boat so far. a lot more fun than my Compac16.

Jon

[Be Free]

Welcome aboard!

Pictures would make it a lot easier to give advice. I'm sure someone here will be able to help.

[WinSome]

Re: clamp or bolt-on. Repair your transom as needed. Then bolt-on the motor. No more concerns about it disappearing easily!! Use a bit of sealant in the bolt hole. I think our transom had a piece of metal channel over the transom top. About three inches per side.

[kenfyoozed]

I am in the process now of repairing my motor well. My boat had a outboard bracket added. I am not sure if I will reinstall. I have ground down the paint and gelcoat to bare fiberglass. I plan on lying up 3-4 layers of 1708 and finish off with 2 layers of 3/4oz CSM. Each overlaping the last by at least 1/2". Then I am going to build a stainless cover that wraps from inside the motor well over the top and down the transom. This will get through bolted and should strengthen the transom for the Tohatsu 9.8 SailPro.

[OverEasy]

Hi EvenKeel16!

I’ve seen some instances of cracking transoms in the past where the top surfaces looked good but the core was compromised by material degradation and/or delamination of the plywood.

By the nature of how things are processed the plywood can have a resin rich surface layer which preserves it, but below that layer the trapped moisture can have a field day. The resultant flexing can cause the external fiberglass layers the flex and/or delaminate leading to crack formation.

To find this internal degradation you can drill several small diameter holes into the plywood at a variety of distributed locations to check then back fill the holes with compatible resin.

Hope this helps.

Best Regards
Over Easy

[kenfyoozed]

Over easy,

What about drilling a grid of small holes to inject a penetrating epoxy to help stabilize the plywood?

[OverEasy]

Hi Kenfyoozed!

If your gonna try and stabilized degraded plywood insitu then it’s a bit more involved assuming we are still talking about a transom.

First the extent of the degradation has to be identified ( how much area is involved and how badly it’s degraded)
If a small area in a corner less than 10 or 15% of the area then I’d think it might be possible.
If it’s more involved or more than around the immediate area around the engine mount bolt holes then I’d be looking to cut out and replace the transom board or at least splice in a new section. There is a lot of stress imposed by and engine. ( just imagine a herd of stable horses equal to the hp of the engine involved pushing on that area… )

Second if your comfortable with the area involved then you’d need to throughly dry out the plywood.
This is typically done with heat pads or lamps and a vacuum pump.
The area is sealed so a vacuum pump can apply a high grade suction to the area while the heat pads or lamps apply moderate heat to get the moisture to vaporize. Done right this can take a week or more. Moisture is checked with a prong type moisture meter into the plywood.

Third once satisfied that all the moisture is evolved out then you’re gonna need an ultra thin long (long) cure time penetrating epoxy resin (like those made by Epon for electronic work). You’d want to get it into the desired area by a push/pull approach. That is you will need a vacuum held and maintained while at the same time pressure feeding the degassed epoxy resin into the void space. That way the resin can get into all the nooks and pores to fill them in. The push/pull approach works somewhat better than vacuum alone as there can be a fair amount of obstruction in the degraded plywood that may clog things up as the resin moves in.

Note: The vacuum pump will need a resin trap to capture the resin that makes it through.
Resin should feed in from the lowest point
Vacuum should be at the highest point.
There should be more than sufficient epoxy resin to fill the void space plus all the feed & drain tubes plus 20% or more for waste.
.
Please bear in mind that this assumes a relatively small area of degradation.
Lager areas, particularly high stress and critical function sections like a transom with a high horsepower engine, should be opened up and repaired by replacing or splicing.

I’ve used this process professionally over the years for a variety of projects and I’m the first to admit caution is the better road.

Hope this helps.

Best Regards
Over Easy

[kenfyoozed]

Sounds like good advice. Mine seems well enough. No rot noted anywhere and holes from outboard bracket are dry. I thought penetrating epoxy may be able to saturate and make it all one piece mor so than the aged plywood that’s there now.

[Maraquita]

When I did similar work on my 26D I used a hole saw and didn't go all the way through at first. I kept drilling bigger and bigger holes using the same pilot bit and was pleasantly surprised that what I thought would be a disaster only required about a 1.5" hole to reach sound plywood. I finished drilling the hole, filled it with epoxy and smoothed everything out. I wound up covering the the whole area with Stainless as someone mentioned above, there are pictures in the Mods section. The only thing I would warn you about, if you clamp the motor directly to the transom is that most (I have tried 3 different ones) outboards in the 10 HP range will not turn far enough to do much good with out being moved back a few inches by the bracket. The power head will run into the side of the motor well. I grew up with fixed inboards and a rudder, so having a fixed straight ahead outboard doesn't bother me. Some people demand a sharper turning radius.