Re-sealing Transom Door Frame & Swim Platform connections - What type of sealant?

[dsendre]

Last year I noticed that the caulking around my transom door frame and where the swim platform connects to the transom was cracked and no longer water tight, so this off-season I want to reseal everything. I've already removed the transom door frame, scrapped off all the old sealant and also removed the sealant from the swim platform connections. I'm allowing everything to air out until I plan on resealing in March to prepare for my April splash date.

The sealant I removed from both areas just seemed to be silicone. I'd like to replace with something stronger and more permanent to, hopefully, never have to worry about these areas again.

Has anyone resealed these areas and, if so, what sealant did you use? Would an adhesive sealant work best or is that overkill? I was thinking of something like 3M 4000 UV or even 4200. I'm sure those would work, but is there something better?

[jclark003]

I used 5200 between the transom and platform on my last boat and it looked perfect after 10 years. No yellowing or cracking. Alternatively I used a bead of UV 4000 around my fish box and I had bits of it falling off and smearing after 2 seasons. To be fair it wasn't meant to be used for that application and as I understand it, works well as a gasket/adhesive. 5200/4200 probably will last a long time on your platform but will haunt you if it ever needs to come off. I would think silicone for the transom door trim.