new 49ft aluminum powercat

hello all , names mitchell, im new to this forum and im just finishing up the mechanicals on a new jeppeson design power cat being built here in seattle.its my first build after 12 yrs engineering and deckwork on the fishing boats in alaska. i also hold an A and P and worked in and out that world too. the boat is all aluminum , 49 ft loa, 18ft beam , draft around 3ft ,we'll see on slash day. power is from twin 220 hp yanmars, 22in michigan wheels. 2 state rooms, i other bunk , 2 full heads. covered rear cockpit is full on sport fishing. cleaning trough ,prep area with sink, bbq, and a freezer. interior is cherry, exterior was shot with glass bead. only paint is the usual bottom stuff. we should splash next week some time. next were doing a 56 ft shallow draft seiner. pics are 4-5 months old. i'll load up more recent pics soon. comments, questions,? thanks mitchell

 

Mitchell, nice looking boat!

I'm curious how you insulate an aluminum boat? Do you use a spray foam, or foam sheets? If you wanted the insulation to be thicker than the stringers, how would you attach the ceiling and furniture to the framework?

 

we used spray foam and 1 and 2 in rigid sheets. spray was done on the pt/stbd interior walls and over both tunnels. about 3in thick . cant remember the r value it gave.cieling was also shot with spray. if the alum ic wiped down clean, spray foam adheres nicely . then we attach wood cleats or strips to the metal structure to secure the interior. as far as building up taller then the stringers are thick, just add another layer of spray.rigid sheets on flat,square vertical bulkheads. hope this helps. mitchell

 

Mitchell, thanks for the description.

Do I understand that you only use the foam sheets on flat surfaces, such as the bulkheads? What type of sheet foam do you use. Is this type of foam too stiff to install on curved surfaces, or is it just too much bother to fit, compared to spraying with foam? Why don't you also spray the bulkheads?

 

we only used it on flat bulkheads in accessable areas for apperance.secured with epoxy weld it studs, push insl. over it, fender washers and nylocks. we also just used 5200 sealant dollpos and flat braced with 2x4s to stay in place and cure. you can get the 1 inch thick stuff to bend with some gentle curves,available at any home improvement store.1 and 2 inch thick pink and blue. not expensive. spray is. mitchell