- Attach a block of KING StarBoard to the transom with stainless steel screws and then attach the transducer to that.
- Use 3M 5200 Adhesive and Sealant to attach a block of cellular PVC to the transom without using screws and then attach the transducer to that.
- Attach the transducer directly to the transom.
Option 1 was my original intention only because KING StarBoard is HDPE material, and I am assuming that it will hold the transducer screws quite well. Also, if necessary, the block of KING StarBoard could easily be removed in the future and the holes properly filled.
Option 2 was recommended by an installer at the marine shop which installed my new outboard last year. I have confidence in the shop, although he was not the installer of my outboard and I do not know his background. He said that cellular PVC (which I already have) would be appropriate and much less expensive than KING StarBoard and would work just as well, and that the 3M5200 Adhesive and Sealant would form a strong bond between [cellular PVC] and the gelcoat on the transom. He stated that he does this on all the inflatables they sell, and recommended spreading the 3M5200 Adhesive and Sealant over the entire back of the block of cellular PVC.
Option 3 is the only other alternative I can think of, and I expect that either option 1 or option 2 is preferred, but I want to leave it open for comments and advice.
I have read the materials posted previously on this site, and appreciate the advice given previously. Up to this point, I am unable to find any downside to using the 3M 5200 Adhesive and Sealant.
So, here are my questions:
Q1: Which option would you choose?
Q2: Is there any downside to using the 3M5200 Adhesive and Sealant, other than that removal of the block would be difficult, if at all possible?
Q3: If I use the 3M5200 Adhesive, would it be sufficient to just use it at the edges, or do I really need to spread it all over the back of the block?
Q4: And last, is the use of cellular PVC (such as is used in Koma, Azek and other such "plastic" boards) an appropriate alternative to KING StarBoard?