Alden O Boat Mk I

Description

Overview of the Alden O 18 Sailboat The Alden O 18 (also known as the Alden "O Class" or simply the Alden 18' O Boat) is a classic wooden one-design daysailer designed by the legendary American naval architect John G. Alden. Introduced in 1921–1922, it was created as a safe, versatile trainer and recreational boat for the choppy waters around Marblehead, Massachusetts. This fractional sloop features a round-bottomed hull with a centerboard for shallow-water access, generous freeboard, and a deep cockpit, making it stable and forgiving for beginners or families while offering responsive performance for club racing. The "O" designation likely refers to its class marking on sails, and it was optimized for day sailing in coastal conditions, emphasizing ease of handling over speed. Production was limited, with only about 20 examples of the initial Mk I version built before 1931, though a revised Mk II proved more popular. As a wooden boat, it's an "orphan" design today, with plans available for homebuilders or restorations, but surviving examples are rare and prized by classic boat enthusiasts.

Construction Details

Designer John Alden
Builder Graves Yacht Yard
LOA 18.250 ft
LWL 15.500 ft
Beam 6.170 ft
Displacement 1300 lb
Ballast 450 lb
Max Draft 3.750 ft
Min Draft 0.920 ft
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The standard boat dimensions

i 16.08 ft
j 5 ft
p 23.67 ft
e 14.25 ft
p2 -
e2 -
i2 -
j2 -

Sails

Sail Type MAINSAIL
Foot * 14 ft - (4267 mm)
Tack Angle * 88 °
Diagonal * 14 ft - (4267 mm)
Head (inches) * 6 in - (152 mm)

Disclaimer. Boats are not all the same -- even when produced in the same factory of the same model. Sailrite does its best to publish accurate dimensions, but we often find it worthwhile to have our customers measure their boats carefully before we produce kits for them. You should take the same precautions, especially when the data is not from Sailrite. The information on this site is not guaranteed to be accurate. Sailrite offers this content as a service to our community, but takes no responsibility for the reliability of the data provided.