Last time I had PT-15 running I had taped it completely so there would be no water entering from the top. I did however get water ingress from one of the propeller shafts. For this reason I decided to add some extra grease to the shafts. To do so I had to drill holes in the top of the shaft housings I made and inject some grease using a blunted needle. After adding grease I glued the holes shut. Then I hope I won't have to do that after I have added the deck.
Another thing. I believe I still have signal loss. I intend to try replacing the receiver and see if a new receiver solves the problem.