Body, lines and sheer plans, oh my!
Unless you’re a boat builder, shipwright, marine architect or somehow otherwise involved in the marine industry, there’s every likelihood that you’re not familiar with body plans, lines plans and sheer plans. But as a woodworker, you’d be well advised to get acquainted with them.
The three plans, together, are generally referred to simply as “lines”. Lines (formally called water lines) and sheer provide elevational and plan views. Body plans provide sectional contours at various “stations” along the length of the vessel. Traditionally, all three take advantage of the symmetrical nature of most vessels and are laid out as “half” plans. The body plan, however, shows stations running for and aft from a common vertical centerline.
The body plan allows the loftsman to create templates for structural members. By coordinating the dimensional information from all three plans (triangulation), curved pieces for structure or plating can be created. In this regard, “lofting lines” is closely related to the layout methods used by traditional French framing carpenters, l’art du trait. (For more about l’art du trait and traditional French carpentry, visit Patrick Moore’s website, historicalcarpentry.com)
An understanding of marine lofting methods or l’art du trait, will allow the amateur or professional woodworker to explore new design possibilities while working with complex curved or flat surfaces.
And, if for no other reason, an understanding of “lines” will allow you to build “half hull” models to be given to all of your boating friends.