Spongy Transom

[spike_michael]

I got down deep under the "splash well" in the back of my Glasspar and found that the transom plywood is soggy wet.
I found out after taking the boat for a cruise Saturday.

Ok this is bad.

So I am wondering why Larson (the OEM) had exposed plywood there not sealed etc... It appears to be a single thickness of 3/4" plywood. I do not believe the transom fiberglass is thick enough to make up the 2" I would expect back there. There is also an aluminum angle bracket which has every appearance of being original, which I can only assume is there for additional rigidity. The mounts for the outboard (on the outside of the transom) appear to have a similar "L" bracket running vertically under the Merc mounts. I never really thought about them before but now that I am thinking I see they were definately added when this motor replaced the original by the previous owner.

The plywood on the inside of the transom does not appear to be attached to the fiberglass in that it is
A, not sealed to the back of the boat
B. appears to be two pieces no one continuous bak piece,

At first I thought the two pieces were necessary to fit it under the engine well for install but I dismissed that because the manipulation of the plywood would be about the same for one side as the whole back.

Questions...

How thick should the transom be? 90 HP on a 15' boat?

Should the transom be a single piece of plywood or is two pieces o.k.?

Is it necessary to affix the plywood to the fiberglass or is the apparent method (bolt together) this was installed with bot adequate and advisable?

i am trying to figure out the photo posting capabilities of this site but it will have to happen on another night... bedtime now.

 

[Kevin70]

Re: Spongy Transom

You have yourself a project. You really need at least one and a half inches to safely hold a 90. I would tear out all of the wood, beef up the inside of the hull with a few layers of mat, put in a full sized, resin slathered double layer of 3/4 ply, and glass over everything with mat and roving. This may sound overwhelming, but if you deside to take it on, this is the best place to have people talk you through it.

 

[sdunt]

Re: Spongy Transom

been there done that.. Yes, the replacement transom needs to be attached to the external skin of the boat.

Check my shareaproject for steps I went through in transom replacement.

 

[spike_michael]

Re: Spongy Transom

sdunt,
Since you have "been there done that" and I have extremely limited experience with fiberglass, any suggestions on product and sources?
For example Kevin mentions mat and "roving" I asked about roving locally and got met with a blank stare. Of course the guy behind the counter also had a blank stare the day I asked for a starter solenoid with four poles on it and he said "they only make three" then I matched one up five minutes later... so... sometimes it is tough to live in the sticks with an IQ more than ten times your shoe size... he has small feet... I do not...