Beta Marine

Beta Marine

Sailboat Specifications

Hull Type: Fin w/spade rudder
Rigging Type: Fractional Sloop
LOA: 25.98 ft
LWL: 20.25 ft
S.A. (reported): 309.00 ft²
Beam: 7.54 ft
Displacement: 3,650.00 lb
Ballast: 1,530.00 lb
Max Draft: 4.79 ft
Construction: Plywood/FG
First Built: 1958
Designer: Ben Seaborn

KLSC Leaderboard

KLSC Leaderboard

Sailboat Calculations

S.A. / Displ.: 20.91
Bal. / Displ.: 41.92
Disp: / Len: 196.23
Comfort Ratio: 17.40
Capsize Screening Formula: 1.96
S#: 3.19
Hull Speed: 6.03 kn
Pounds/Inch Immersion: 545.56 pounds/inch

calculation mobile

2 nd ad half width

3rd ad full width

Rig and Sail Particulars

I: 26.75 ft
J: 8.00 ft
P: 31.00 ft
E: 13.00 ft
S.A. Fore: 107.00 ft²
S.A. Main: 201.50 ft²
S.A. Total (100% Fore + Main Triangles): 308.50 ft²
S.A./Displ. (calc.): 20.88
Est. Forestay Length: 27.92 ft

Sailboat Links

Designers: Ben Seaborn
Associations: Thunderbird Class Association
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Some THUNDERBIRDS have been built of molded FG with aluminum spars. A "cruising deck" design was introduced. Most have been built from plans now supplied by the class association. See the class web site for details.