As the weather is getting cold to work with sealants outside, installing the thru-hulls will have to wait until the spring. If we'll have a cold spring, I might make a tarp around the hull to be able to heat it up, but we'll see. Until then the interior can be easily heated and working inside with epoxy is possible, so I'm planning to install backing plates. The hull of the Scanmar 35 seems to be quite thick, I measured it to be 14mm (solid GRP laminate + the gelcoat), but some extra thickness might still be good to help distributing the load. I consider this as a "once in a lifetime" job and since there is time till the spring, I want to do it properly, so hopefully I'll never have to do it again. Some people use plywood for backing plates, but I was concerned that if anything goes wrong and water gets in it will rot. So I followed the advice of this article instead and got some solid G10 GRP sheets in 3mm and 10mm thickness from eBay. The plan was t