Frame patterns on keel and stem. stem pattern used to form keel and place stem. this is the real zephyr, a 16 foot stepped hydroplane! reproduced from the original offsets and plans by a.a.apel.. Designers, plans & kits a to m: 16′ mckenzie river driftboat plans and construction manual (from altair industries, ft. collins, colorado); adirondack guide boat (cedar strip adirondack guide boat kits, north ferrisburgh, vermont); advanced multihull designs (amd, high speed passenger and vehicle ferries); aeromarine research (tunnel boat design books and software). Scroll down this page for many more plans. this a page of links to some favourite free boat plans at intheboatshed.net.they’ve been chosen because they are derived from traditional boats, or in some cases simply for their usefulness..