Here’s a pretty good article from Sailing Magazine on mounting deck hardware.
“Attaching fittings properly isn’t difficult and protects your boat for the long-term.
At some point in its life, every boat will need a deck fitting replaced or will develop a leak that must be corrected. And while replacing deck hardware is not a complicated operation, doing it incorrectly can cause serious damage down the road. Install a fitting properly and you have a sturdy piece of hardware set for the long haul. Do it incorrectly and you face rotten core or compromised bulkheads.
Owners may choose to replace a fitting because they want to upgrade to something stronger and lighter or because they have concerns about the age of a piece of hardware. A few basic steps can achieve a good, long-lasting seal between a fitting and the deck.
Remove old hardware
The first step is to remove the hardware or fitting that will be replaced or rebedded. In most cases, removing fittings is not difficult as the sealant is often broken down enough to not put up too much of a fight. If the hardware was originally bedded with 3M 5200 adhesive sealant, you may have to go to drastic measures to remove the fitting. More on the best sealants to use later.
Start by removing all… READ MORE.