Hartley 21 21′ (6.4m) trailer-sailer. for construction in plywood or as a mould for grp/frp. beam 7’11". can be built as centreboarder, single or bilge keeler.. Free boat & ship plans boats, ships & anything that floats. this section is dedicated to free boat plans. each plan is available as a zipped file and will either. Free plans? yes, they are really free, hundreds of them. the plans offered at this site are free public domain boat plans. choose a category at the left, choose.