How To Read Lines Plans

A practised glance at the waterlines, sections and buttocks can tell us much about a yacht’s character

- Tom Cunliffe

Seeing a yacht in the flesh and sailing her in a wide variety of conditions is enough to tell an experienced mariner a lot about her character. When the only information available is a photo and a lines plan, things can be very different. The image gives a general impression, but it’s the plan that really dishes the dirt.

These days, the classic lines plan has fallen into disuse for most amateurs. The reason is simple. In contrast to the average craft designed before World War II, the hull shapes of today’s production cruising yachts are unsophisticated, delivering good performance in fair weather by virtue of a relatively low wetted area, a clean run, a deep fin keel and a spade rudder.

The lines plan of such a boat is of scant interest compared with the drawings of the deep-bodied, three-dimensional types of yesterday. A profile drawing is generally all that is offered, because a lines plan would do little to improve on it.

Before this revolution took place, sailing magazines rarely hit the news stands without at least one lines plan of a new boat. Studied with an educated eye, these revealed a great deal. They were pored over in yacht club bars, scrutinised on kitchen tables by yachtsmen home from the office, and generally assessed for the nature of the vessels about which they spoke so fluently.