Windmill (sailing dinghy)

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Class symbol
DesignerClark Mills
LocationUnited States
No. built5700
Builder(s)Johannsen Boat Works
Lockley Newport Boats
Advance Sailboat Corp.
RoleOne-design racer
Displacement198 lb (90 kg)
Draft4.17 ft (1.27 m) with the daggerboard down
ConstructionFiberglass or plywood
LOA15.50 ft (4.72 m)
LWL14.50 ft (4.42 m)
Beam4.75 ft (1.45 m)
Hull appendages
Keel/board typedaggerboard
Rudder(s)transom-mounted rudder
Rig typeBermuda rig
SailplanFractional rigged sloop Masthead sloop
Mainsail area85 sq ft (7.9 m2)
Jib/genoa area34 sq ft (3.2 m2)
Spinnaker areanone
Total sail area119 sq ft (11.1 m2)

The Windmill is an American sailing dinghy that was designed by Clark Mills as a one-design racer and first built in 1953.[1][2][3]

The Windmill hull design was developed into the US1 single-handed catboat in 1974.[4]


Originally intended to be amateur-constructed from four sheets of plywood, the boat was also commercially manufactured from fiberglass. The design was built by Johannsen Boat Works, Lockley Newport Boats and Advance Sailboat Corp. in the United States, but it is now out of production. A total of 5700 examples of the type have been completed.[1][3][5][6][7]


Windmill on a trailer, showing hull shape

The Windmill is a recreational sailboat, built predominantly of plywood or fiberglass in the form of a double hull with a foam core, resulting in an unsinkable boat. It has a fractional sloop rig with aluminum spars. The boat and is sailed only with a jib and mainsail, no spinnaker and no trapeze. The hull has a rounded plumb stem, a conventional transom, a transom-hung rudder controlled by a tiller and a retractable daggerboard. It displaces 198 lb (90 kg),[1][3]

The boat has a draft of 4.17 ft (1.27 m) with the daggerboard extended and 6 in (15 cm) with it retracted, allowing beaching or ground transportation on a trailer or car roof rack.[1]

For sailing the design is equipped with jib and mainsail windows for visibility. It also has an internal 2:1 mechanical advantage outhaul, a 4:1 boom vang controlled by the boat's skipper and a 4:1 Cunningham. The boat has adjustable jib fairleads and a mainsheet traveler, plus an Elvstrom bailer.[3]

The design has a Portsmouth Yardstick racing average handicap of 90.2 and is normally raced with a crew of two sailors.[3]

Operational history[edit]

In a 1994 review Richard Sherwood wrote, "the Windmill is a high-performance sloop that can be built from plans or from a kit, or purchased complete. She is very light and planes quickly. Class rules are strict, and neither spinnakers nor trapezes are allowed. With a double hull and closed-cell foam, the boat is unsinkable. This type of construction also results in a very rigid boat."[3]

The boat is supported by an active class club, the Windmill Class Association.[8]

Windmill racing by a mark


See also[edit]

Related development


  1. ^ a b c d McArthur, Bruce (2020). "Windmill sailboat". Archived from the original on 21 August 2020. Retrieved 21 August 2020.
  2. ^ McArthur, Bruce (2020). "Clark Mills 1915-2001". Archived from the original on 20 August 2020. Retrieved 21 August 2020.
  3. ^ a b c d e f Sherwood, Richard M.: A Field Guide to Sailboats of North America, Second Edition, pages 58-59. Houghton Mifflin Company, 1994. ISBN 0-395-65239-1
  4. ^ McArthur, Bruce (2020). "US1 sailboat". Archived from the original on 20 August 2020. Retrieved 21 August 2020.
  5. ^ McArthur, Bruce (2020). "Johannsen Boat Works". Archived from the original on 22 August 2020. Retrieved 21 August 2020.
  6. ^ McArthur, Bruce (2020). "Lockley Newport Boats (USA) 1964 - 1988". Archived from the original on 6 August 2020. Retrieved 21 August 2020.
  7. ^ McArthur, Bruce (2020). "Advance Sailboat Corp. 1960-1980". Archived from the original on 20 August 2020. Retrieved 21 August 2020.
  8. ^ McArthur, Bruce (2020). "Windmill Class". Archived from the original on 22 August 2020. Retrieved 21 August 2020.

External links[edit]