Ferro cement boats can be wonderful masterpieces!
My friend (now 81) built himself two amazing sail boats - one 60' and on 40' using the ferro cement method. It is labour intensive, but the results are amazing (if you know how to finish the cement well).
Just looking at his boat, you couldn't tell that it was cement.. it looked exactly as a fibreglass boat would, until you knocked on the hull. They are solid, beautiful boats that are still sailing strong today (40 years later).
If I had money, time and the patience I would certainly consider building a cement boat. They are like any boat though.. improperly built, or improperly maintained, and they will bite you some way or another.
My friend ran aground on his boat and punched a 6" whole in the hull - the fix was to mix some concrete on the spot, apply, let dry, and away he went!
google ferro cement.. you can see alot of construction blogs and step by step pictures.