Lively 28 28’6" (8.69m) cruising trimaran. for construction in plywood or as a mould for grp/frp. main hull beam 7′. draught 2′. can use either inboard or outboard.  altair industries driftboat plans altair offers complete plans and a construction guide for a 16′ mckenzie river drift boat. (added: 2-dec-2003 hits: 44766) my. 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.