A tip from my boating days... When you are attempting to seal anything keep in mind that the caulk product is there to form a gasket not to glue things down. You should apply the caulk and lightly tighten the screws/bolts etc., and then let it cure for 24 hours. Then after it has cured tighten everything down.
If you apply and then tighten you merely squeeze the caulk out from where it needs to be.
By waiting until the new "gasket" has cured before torquing down the fasteners you get a long-lasting watertight seal.
:C
