Since many volumes have been written on the broad subject of boat design, this month s column is simply a crash course in design terminology. In the Spring issue , we looked at a selection of production boats from Canadian-born designer Ted Brewer. Most glossy boat brochures include a profile line drawing from the designer that provides a lot of information about the sailing characteristics and style of either a new or classic boat. One of the most prominent features of these scale drawings is sheer -the amount of spring or bend to the deck line of the boat. Traditional designs typically have lots of spring for a pronounced sheer, while modern racers have little or no sheer.
Transoms come in a variety of shapes, slants and sizes.
In this case, the slope of the Whitby resembles the profile of the back of a spoon held with the handle about 30 degrees below horizontal. Freeboard is a measure of the height of the topsides from the water to the sheerline. And while high freeboard creates lots of interior volume in a cruiser, it also increases windage and can lead to a tender boat with a high centre of gravity. Both boats have identical hull shapes underwater, but Killing has reduced the freeboard on the racier 30M to reduce weight, windage, centre of gravity and pitching moment. Under the waterline, we observe differences in hull, or the degree of downward curve of the hull from the ends.