I will need to replace the transom in my little 14' aluminum boat before I take it out this season. I was going to use plywood and stainless hardware, but my question is what I need to use to seal the bolt holes. Do I use plain silicone sealant (tube type) or are small rubber gaskets better? Or am I totaly off and need something different? this doesn't look like to hard a job, I just want to do it right so it will last at least a few seasons and first and foremost be safe.