When thinking of adding a snorkel some might want to think of outboards. Though you add a snorkel you may still wash out and stall it might be great to add this little jewel the Pioneer tailgate does double duty as a transom, take a look.
Great photo's, now just add a blower motor inline up high and it will be pressurized. So if you have any leaks it won't suck in water it will blow air out. Check my supercharger posts. it would work great and be a safety item for you. I used a 3" blower but you could use a smaller blower or use adapters. Just an idea. I like what you've done.