by Weston Farmer
LOA17' 11", BEAM 6' 6', DISPLACEMENT 1,635 LBS.
A revolutionary new handling of an old principle makes this design the one for the skipper who demands the ultimate in boat performance
This beautiful-running little boat is named Trumpet. Shown here powered with a Mercury Mark 55 40 hp motor, turning an 11” x 11” propeller at 3,000 rpm (motor 5,000 rpm), she is making a measured 24 mph with slip at 15 per cent. This is on an all-up weight of 1,635 pounds, or more than 40 pounds per horsepower. Note her very fiat, sprayless wake. Her freeboard forward is 33%”, and aft it is 26 ¼” at the transom-sheer junction. Trumpet more nearly approaches a boat of normal form than do four-sided sharpened mortar boxes, hence she is very soft in a seaway, rises bodily throughout her running range without appreciably changing trim. She turns like a pony, yet tracks course like an express train. She was built to my lines here for John W. Rollinson, Jr., of St. Simon’s Island, Georgia, by George Stevens to prove some ideas both Mr. Rollinson and I had about seagoing planing hulls. The dope says she’d have to weigh 400 pounds less, or have 50 horses to produce 24 mph. Cross-checks of these figures with appropriately lighter loads have produced speeds of 26.5 to 27 mph. She is therefore about 25 per cent more efficient than the average—a marked increase in general ability. This is due to decalage in her running lines, particularly her keel, which applies to a hydroplaning surface a portion of the general principles of laminar flow found in airplanes with a “Coke bottle” fuselage. This “decalage” (deck’-a-lage to rhyme with garage) is a French engineering term which refers to different angles of incidence in the lift members of a plane, disposed in such a way as to produce inherent fore and aft trim components.
HOME PAGE
