Class5 specs are quite specific with materials and construction just keep that in mind. For example a fibre glass mast ex sailboard would put you outside the class rules.
What acess do you have to construction stuff.... welders, good or basic workshop, lathe, mills, drill press, what is your material supplies like, what do you like working in ?and all that stuff.
Do you want the design basic, med or complex?
HOME WORK: Here is a thought for sail shapes... have a look at things in nature like the wings of birds that fly/ glide well ie. seagull, eagle, albatros etc and what shape do they have?
What is the shape of planes that glide well ie. sailplanes/ gliders, then ask why are they like that?
Post a pic of the sail you were thinking of using flat on the ground and lets have a look at it.
Im also fan of straight axles.... and Aluminium scaff tube.
class5 mid 80's
Mini size yacht im working on ... but could be enlarged to class5 size