RE: Newbie here, how does it all work?
Umi,
You only have 1/2" below penetrable? We give a full 1" below the waterline as penetrable in the NTXBG (unless the hull curves more than 45 degrees inward, then you can stop being penetrable). With only 1/2", my little 22" tramp steamer would be virtually untoucheable - since the waterline is the bottom of the caprail.
Wreno