Foam question

Hey guys, I'm new to the site and thought some of you may be able to answer a question. I am currently doing a massive modification on an alumacraft 1648. The flat front. I've welded up a bunch of stuff on the front and need to run some wire as well as some bolts under the seat. I stuck a little cam down one of the little gaps in the front corner and it did not look like there was much foam up there. I then cut out two 6" holes in the vertical part of the seat and it is quite full of foam. I cut a bunch out but would need to take way more in order to accomplish my task. So my question is, have any of you used the spray can foam (Great Stuff) from the box stores? Was wondering if it retains water at all when it gets wet. I live on the Westside of Washington and we get wet here. Thanks guys. Eventually I will get a very detailed thread on hear about my build.

Here is a quick photo.

Sorry can't help with the foam. Love the rails though it looks really good. The boxes up front, those for lights, or?

Yeah, 4 rigid industries d2's.

You want a closed cell foam, see if it's an open or closed cell foam?

DO NOT use great stuff. It is not closed cell and will hold water. If you are only taking out enough foam to run wires, I wouldn't worry about replacing it.

Yeah, I decided against great stuff. I've got it all it cut out, wires ran and was actually able to stuff more of the (pink foam) into the existing voids than what I have taken out. In the 6" holes I cut I'm installing the Beckson screw out deck plates. Going to roll some stainless or aluminum to fit the OD of the lip on the plate. Cap and weld the one end and the seam, then use the permanent stuff on the cap. Perfect for dry storage and can also act as flotation. I've gone a little crazy on this little boat but it will be fun. Was going to put a Yamaha 40/30 pump on it but I may lean toward a Evinrude etec 30hp. Almost 90lbs less. I have all Yamaha's on my other boat and really like them but they weigh so **** much. Any input on Evinrudes is welcome. I research the $#!% out of everything before I buy and have not done too much research on the rudes. Promise I will get a thread up on here of the build. I have taken photos of the whole process. Little boats are quite fun, my next build will be an alumacraft 2072 tunnel with a tiller. Already have the plans thought up. Thanks guys!

P.S. My goal for this little boat is to catch one of these that is bigger than the boat out of it!