don t listen to the naysayers from wharrambuilders club. they got no idea what alu boatbuilding is, neither the advantages and neither do they know that an aluminium wharram 42ft upwards is not heavier than plywood with fibre and all the toxic things they put in and on the hull. i can say you that you save a lot of money and weight building in aluminium. i make all brackets, shrouds attachments and evverything in alu. as you said with a nice miller system or like we have a fronius tps2700 the entire story about alu welding is becoming to be changed in something very easy even for beginner welders. our hull is 51 ft long and was discussed in the past ones in the wharrambuilders. of course one had to compare my 51ft wharram style cat (which is in the hullsize, full standing headroom the entire hull length, 2,5m maxbeam hull, 8,1mbeam) with the tehini sardin tin-like hull instaed of comparing it with a pahi 52 or the islander 55. there you will see that my hull (20mm keelplate, 6mm up to chine, 5mm sides and roof, 6mm ringframes each 700mm, 45/6mm stringers each approx.270mm, 4 beam 400 by 315mm/6mm thickness) is for its strength you can say light compared to wharram cats of same range. but much much much stronger i say. and 100 % recyclebar, no resins and fibres toxic crab stuf you know. i hope you see thatyou are on the right track. you are not the first one. approx. you are the 4th or 5 th one building alu wharram or wharram style. i will put a crab claw balanced sail on a A-mast in front and a freestanding mast on each hull near the stern and a lugsail on each. all togehter ca. 90m2. cheers chris