Transom Replacement (Again)

[Paddy3101]

I am in the middle of replacing the transom of my Fletcher Arrowbolt 21' (Built around mid 80s). I decided to replace the transom from the outside, as the transom has been butchered before and has many-many holes drilled/filled; hence it is rotten. It looks like it was originally an inboard, but has been converted to an outboard.<br /><br />The question I have is, how much do I need to wrap the new glass around the sides/botton? I was reckoning on about 8-12 inches, with the last 2-4 inches being faired<br /><br />I'm using Expoxy and Bi-axial glass (450 grams/meter^2). Plan on rotating layers by 45degrees. How many layers?

 

[Paddy3101]

Re: Transom Replacement (Again)

Some pictures<br />

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[epresutti]

Re: Transom Replacement (Again)

Paddy...,<br /><br />Weak points are going to be where the transom meets the hull. make sure your wrap the glass, especially at the bottom of the transom. Also since you have access, wrap on the inside as well. The formula I was given was 12:1, if the glass is 1/2" thick you need to overlap 12/2" (6"), 1/4" -> 12/4" (3"), etc..<br /><br />To be safe on my rebuild I overlapped 8" and then on subsequent layers backed off 2", so 8, 6, 4, 2. Then I fared it out from there.<br /><br />Make sure you are binding to bare fiberglass, not gelcoat, you must grind away the gelcoat to get a good bond.<br /><br />I used XM on my transom and it is really solid, the biax should work great, the more layers the better.<br /><br />I hope this helps.<br /><br />Peace.<br /><br />Ed.

 

[lingcod]

Re: Transom Replacement (Again)

ED, Maybe I am mistaken but I thought that the layers should go 2,4,6,8 gradually extending out form the join. My thinking is that in your project, if the 8" layer fails for whatever reason, the the whole thing comes up as one unit. am I wrong?

 

[epresutti]

Re: Transom Replacement (Again)

Ling....<br /><br />You would think it was the other way, but no. large overlap first. I don't know the exact reason, but that is what "the book" (page 15-20 Fiberglass Boat Repair and Mainenance, West Systems #002-550) says and also most of the folks I talk to.<br /><br />In any case you don't want the bond to fail in any way, especially on structural components.<br /><br />Peace.<br /><br />Ed.

 

[Paddy3101]

Re: Transom Replacement (Again)

Thanks for the help. <br /><br />I was planning on doing ~5 layers on the outside, so overlapping 10,8,6,4,2. And a couple of layers on the inside. <br /><br />Also, I have 6inch wide tape of the same biaxial which I was planning on reinforcing around the edges and stringers on the inside. Much easier to get the tape to bond well, than trying to taylor a large sheet around the stringers on the inside.<br /><br />So it doesn't sound like I was far off.