1984 advantage ski boat transom and stringer replacement

[REMAN]

Hi everyone! My name is Mike and Im new to the forums. I have acquired a 1984 Advantage (anybody ever heard of them?) ski boat. It is a 16 ft, walk thru windshield with a Mercruiser 120 hp i/o that runs great and also has good upholstery. Now the bad, I had water coming in through engine compartment and gradualy getting worse. I did some investigating and have found ROTTEN TRANSOM, and rottten stringers. Everybody told me to sell and cut my losses, but I ain't "skeered". Let me tell everyone what I have done so far. I removed engine, outdrive, floor, old transom, and nearly all of stringers. I have removed all foam in the floor and started sanding where new stringers go. I also have started replacing transome and am proud to say the first piece of AC Fir plywood is in. I run out of cloth so I had to stop. I do have a question I would love for someone to answer. The old transom was 2 sheets of 3/4 plywood and the hull measures a 1/4". This of course adds up to 1 3/4". Everything I have read says mercruiser outdrives need to be between 2-2 1/8" Can anyone please help me with this? I will post pics as soon as I can of my adventure.

 

[Woodonglass]

Re: 1984 adavantage ski boat transom and stringer replacement

Re: 1984 adavantage ski boat transom and stringer replacement

Welcome to the iBoats Dry Doc!!

Yep you are correct about the Transom Thickness Requirement. You said the first piece of plywood is in?? Usually you make the entire transom piece outside of the boat and install it ALL as one piece. I guess you can continue to layer it in but it will be a bit harder. How thick is your first piece? 3/4" Are you using Resin or Epoxy. You said you ran out of cloth. What cloth are you using? This will all make a difference in what the final thickness will be.

 

[REMAN]

Re: 1984 adavantage ski boat transom and stringer replacement

Re: 1984 adavantage ski boat transom and stringer replacement

Thanks for the welcome. I am using resin because money is an issue right now for us. As for as the cloth I believe it is a 6 or 9 oz from Evercoat. The boards are 3/4" and the second piece is alot shorter than the first Thats why I didnt go ahead and put it in. Thanks

 

[Woodonglass]

Re: 1984 adavantage ski boat transom and stringer replacement

Re: 1984 adavantage ski boat transom and stringer replacement

Well, typically with Resin you use CSM or Woven Roven NOT Cloth. If you do use cloth you MUST use a layer of CSM to get proper adherance. How did you Glue the plywood to the Outer skin of the boat?

 

[REMAN]

Re: 1984 adavantage ski boat transom and stringer replacement

Re: 1984 adavantage ski boat transom and stringer replacement

Well that makes me nervous. I coated the plywood with resin then put my cloth over it and coated again. Then I coated the boat shell with resin and placed the transom board in against it. Then I run screws from the inside out through transom board and existing holes and attached to 2x4's to pull everything tight together. I may be wrong but its holding like you wouldnt believe. What is you recommendation from this point since I obviously have messed up. Thanks

 

[Woodonglass]

Re: 1984 adavantage ski boat transom and stringer replacement

Re: 1984 adavantage ski boat transom and stringer replacement

Your terminology of CLOTH is making me a bit nervous. Can you be more specific of exactly what it is called. Can you give me a website or something where I can go see what the stuff was?

 

[REMAN]

Re: 1984 adavantage ski boat transom and stringer replacement

Re: 1984 adavantage ski boat transom and stringer replacement

The website is www.evercoat.com it is there Sea Glass Fiberglass Cloth item #100918. I now see the woven roven you were talking about. Well its to late now for that. I do have some fiberglass matting that I bought

 

[Cadwelder]

Re: 1984 adavantage ski boat transom and stringer replacement

Re: 1984 adavantage ski boat transom and stringer replacement

Well that makes me nervous. I coated the plywood with resin then put my cloth over it and coated again. Then I coated the boat shell with resin and placed the transom board in against it. Then I run screws from the inside out through transom board and existing holes and attached to 2x4's to pull everything tight together. I may be wrong but its holding like you wouldnt believe. What is you recommendation from this point since I obviously have messed up. Thanks

The problem you have with just cloth is the uneven surface of the outer skin of your hull. A layer or three of CSM (Chopped Stranded Matt) would have filled any uneven areas MUCH better and provided a much better bonding. If both of your surfaces where extremely flat you may get by with what you have done, but I would be a bit leary of it. In this case I really hope you used Marine Grade plywood for this transom? The marine grade is much flatter and won't soak up resin like other materials (leaving more resin to make a better bond.

 

[Woodonglass]

Re: 1984 adavantage ski boat transom and stringer replacement

Re: 1984 adavantage ski boat transom and stringer replacement

I asked Cadwelder to join in on this and I am going to agree with him. In the interest of safety and doing things right I have to say I would suggest doing it over. Using cloth and resin is NOT the recommended method. Sorry. Can you get by with it. MAYBE!! It's up to you. It
s not the Woven Roven you want to use either. What we are talking about is Chopped Strand Mat CSM. 1.5oz material. It absorbs the resin and the resin disolves the strands and bonds everything together while at the same time filling any gaps and irregularities in the mating surfaces. Cloth does not do that and at the same time can a most times will leave air pockets in between the mating surfaces which can make the bond weak. I am NOT confident that your transom will be structurally sound having been put together in this manner. I am not 100% certain of this, it is just my opinion. Up to you to make the decision. I'm just one guy. Maybe others with chime in.

 

[REMAN]

Re: 1984 adavantage ski boat transom and stringer replacement

Re: 1984 adavantage ski boat transom and stringer replacement

Thanks for the input. Im going to look at closer. I just hate to start over but I will if I see or feel any thing that may be weak. Ill let everyone know before to long. Thanks