Stitch-and-glue boatbuilding learn introductory and advanced modern plywood boatbuilding techniques suitable for heavy-duty boats. john harris—august 20–26. What is lapstitch construction? clc’s exclusive lapstitch™ construction . patent no. 6,142,093 . the strength of the lapstitch™ joint is such that the designs. Intro: build a greenland kayak. this instructible will teach you how to build a 17 foot long greenland kayak that will weigh between 30 and 40 pounds and cost less.