transom board replacement

[bbenkaz]

Hello again everyone. I am replacing the transom board for a friend in a late 50's alumacraft runabout. Is there any problem with using a treated board and then wrapping it in fiberglass so the fiberglass creates a barrier between the aluminum and wood? I know that the new treated lumber will eat the aluminum but was not sure if glassing over it caused any problems.

Thanks
Ben

 

[wan2live]

Re: transom board replacement

I dont see a problem with that since the fiber glass is covering the treated wood but I am not an expert on boats by no means just my 2Cents.

 

[gcboat]

Re: transom board replacement

There have been many pro's and con's concerning glassing over PT lumber. It could possibly be a good fix if the lumber has been completely dried out. Others say the chemicals in the wood itself will cause a bonding issue with the resin. I've never used PT myself in a boat so I have no first hand knowledge in that respect. However there is no reason to believe that once completely dried it wouldn't do the trick. I know marine grade ply (Okume,etc.) is a bit more expensive but it would be the way I'd go. Just a personal preference. Also try to use an epoxy resin - much stronger and in my opinion will bond better than polyester.

 

[Mano del Sol]

Re: transom board replacement

I gotta wonder what the point of using PT lumber is if it is going to be wrapped in fiberglass anyway.

 

[wan2live]

Re: transom board replacement

I gotta wonder what the point of using PT lumber is if it is going to be wrapped in fiberglass anyway.

Very good point I thought aboput that after I posted.

 

[CATransplant]

Re: transom board replacement

The transom board on those little aluminum boats was designed to be replaced from time to time. Personally, I see no reason to worry that much about them. It only takes a short time to replace them.

I use a combination of ACX plywood thicknesses to suit the required thickness, sealing the plywood with either paint or varnish on all sides and edges. I use simple Gorilla glue to bond the plywood together.

These boards seem to last between 5 and 8 years on my boats. Some guys use oak planks for the job.

Bottom line is that you'll end up replacing whatever you put on there in a few years, so why worry. Get 'er done and get on the water.

 

[bbenkaz]

Re: transom board replacement

Well I want to make it last as long a possible and it is going to have a 40HP motor on it so it needs to be strong I don't know that laminating plywood together is what I am looking for. I know that it does not matter all that much since it is going to be glassed but I would like to know that if the glass gets comprimised that the wood won't instantly rot.

Thanks for the advise
Ben

 

[tashasdaddy]

Re: transom board replacement

i agree with CAT, that's what i do on tinny's

 

[bbenkaz]

Re: transom board replacement

I got a nice piece of Black Locust it is rot resistant and strong and heavy so all is good.

 

[CATransplant]

Re: transom board replacement

I got a nice piece of Black Locust it is rot resistant and strong and heavy so all is good.

Shame to cover up that nice wood with fiberglass. Really. The transom board on an aluminum boat doesn't get all that much water. Why not put a couple of coats of polyurethane on that pretty wood and let it show?

Seriously, It's not like the wood is soaked in water, since it's up on the top of the transom area. Glassing it is pretty unnecessary, and adds thickness. If you have an aluminum molding that is a cap for the transom, getting the thickness just right can be tough with a glassed board.

It's all up to you, of course, but I've seen old Alumicrafts that have been sitting outside for years with the original transom boards intact. As long as the wood isn't soaking in water, it lasts pretty well. I don't know what wood they used, but it holds up pretty well.

 

[iwombat]

Re: transom board replacement

If you use good void-free plywood it won't rot very fast if water gets in. You certainly don't want to use PT to bolt up against aluminum. The chemicals may react with the aluminum and compromise your hull. Stick with fiber-wrapped ply and you'll have good service life.