Study plans are available for some of these designs – remember a study plan gives you more details and a wood materials list usually on two a1 sheets, so that you can cost out a project before ordering the full plans.. Mill creek 16.5. a tandem sea kayak with a cockpit so large that it is almost an open boat, with huge buoyancy. a very versatile boat that can be upgraded to row with a sliding seat or sail fast.. Built by peter randall – the total including engine, trailer and everything to get it going was about $17,000 australian. i’ve been quoted around $35,000.00 by boat builders. peter randall – lemontree passge, australia. built by alex neymark – $44,000 includes motor & trailer, everything! only top of the line materials were used including many custom made parts..