Leak in berth

I have a leak in the berth on the port side coming from 2 areas. One is from the port light and the other I believe is from the support for the rail attached to the gunnel. Does this sound right or is there a common known problem other than the rail support? Also I plan on using Dow 791 or 795 for bedding of the handrail support and to seal the window. Am I on the correct path? Thank you for any help.