go here:
http://www.rc-submarines.com/id119.htm
that picture at the very top, "Bow hold down" is almost exactly what i did. instead of fiberglass, i just took some scrap plastic lying around. i used a small stainless steel nut and bolt set from my old Piccolo helicopter parts box and instead of using a brass tube, i used a plastic styrene tube. i used slow dry 24hr epoxy and glued the blue plastic to the hull as well as the styrene tube to the hull by literally submerging both the styrene tube and bolt; i bascially filled up the little "pocket" i made in the hull with epoxy. after a few days when the epoxy was dry, i took my mini pin vise and drilled a little bit through the nut to clear a hole in the epoxy for the bolt.
http://www.rcuniverse.com/forum/upfi...21/Lg18208.jpg
here you can see the blue plastic i used instead of the fiberglass. the top part of the hull is at the bottom of the picture and that tiny hole on the left has the nut behind it, but you obviously can't see it. on the right of the top part of the hull you can barely see the peice of clear styrene plastic i glued. this flap slides under the remainder of the top of the hull that is permanently glued to the bottom of the hull and encases the rudder and dive plane linkages. this flap at the back of the top part of the hull wasn't actually my idea, but rather Mark Jones' idea. if i had his permission i could send you his pics of his alfa sub that was the inspiration behind mine.