Those are not covers; Iknow, they sure look like covers! They are actually cast plates that are part of the chain plate system. Check out the schematic on the Beneteau parts website to see the configuration of your boat. The short version to rebed properly is to rig a temporary shroud on the side you are working on & loosen the shrouds a bit on the opposite side of the boat. Remove the terminal hardware from the chain plate that you are rebedding. Disconnect the threaded rods that terminate inside the boat, under the setees cushions. Unscrew the bolts that attach to the deck plate from beneath the deck. Pull out the assembly from above deck, clean off all of the old caulk, recaulk, & reassemble. Check out the archives, I am sure that there are more detailed instructions available.