questions from a newbie

[onairos]

My friends and I have become interested in building our own boat recently. We live in southeaster New Brunswick.
We would like to be able to live on it during the summer so we'll be designing it with the intention of 3-4 people living on board comfortably, with deck space enough for about 8 people altogether if we have visitors. My biggest question is what kind of design we should use to make this sort of boat. We'd like something fairly stable so that we could take it across the Northumberland Strait or down the eastern coast a bit. Just as a note, most of the boat would be constructed of metal, as my friend is doing this as a welding project. Thanks for any help.