Concensus seems to recommend hot-dip galvanized rebar, which is less prone to rusr/corrosion. Not sure where to get it. 1″ galvanized chicken wire is the preffered mesh. Planning any thru-hull openings (propellor-shaft, portals, sump outlets, etc., is part of the design and an epoxy coating seems to help with adhesion of cement in those places.
Frame is usually galvanized pipe; rebar, inside and out; then about 5 layers of chicken wire, inside and out.
Hand lay-up, or shor-crete are the 2 main ways.that seem to work best. Working inside a shop/under cover, helps, and access to burlap and clean water are a must. Curing is critical.
What I know, I know from study. Connect with me, off-list, and I’ll see what I have and may be able to send some links, later on.
Never be afraid to try something new…
Remember, amateurs built the ark, professionals built the Titanic.