Tad Roberts

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Douglas Fir 28' Displacement Boat

Construction:
Length: 28' 0"
Beam: 10' 6"
Draft: 2' 9"
Displacement: 11,600 lbs (half-load)
Power: 170 HP twin Yanmar 4LH-DTFs
Top Speed: 20 Knots
Builder:

Comments

With a deep rounded forefoot evolving into hardchined shallow vee sections aft, Douglas Fir is a real hybrid. The fastest in this group of semi-displacement hulls, the vee sections will semi-plane the stern, provide dynamic lift, and improve trim. Some are of the opinion that a boat this wide is no good running in a big sea, but I think rudder size may have as much to do with it as anything. Many fast boats are equipped with tiny rudders to reduce drag, but they also reduce turning moments. Douglas Fir has two oversize rudders. It's a balancing act getting a hull that's optimum in many conditions at high speed, trading weight and section shape against LCB location.

Is she seaworthy? The design is as able as I can make it, but seaworthiness involves more than just design. Construction must be good, equipment must be well made and maintained, and the crew must be competent. As far as design goes, a seaworthy boat includes; adequate freeboard, reasonable beam and draft (not too much beam and enough depth to get heavy weights down low), watertightness, and stability (low VCG). Providing for safety equipment, watertight bulkheads, and decent visibility under difficult conditions all add up to seaworthiness.

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