Crew: 1 man crew. For racing, ideal weight of sailor should be between 60 and 95kgs.
Dimensions: 4 meters in length, 1.2 meters in width and ±72kg.
Sail Area: 9.45 square meters.
Class: Restricted (hull shape remains the same from year to year)
Characteristics: Single-trapeze planing dinghy with conventional kite and is sailed in over 60 nations.
Difficulty Level: Intermediate

The OK dinghy is an International class with strong fleets in the UK, Denmark, Sweden, Germany, Belgium, Poland as well as Australia, New Zealand, India, Korea, Thailand, Malayia. It is the singlehander sailed in the Asian Games every four years. In the UK there is a strong open meeting circuit as well as International competition just across the channel, for example Keele Week, the Spring Cup at Medemblik & Warnemunde Week. Clubs racing for the OK is mainly on the East and South coasts.

Technically speaking, the OK Dinghy is a single handed dinghy, built of wood, GRP or 'composite'. OK Dinghies can be home built of professionally built and sailed by men and women between 60 - 95 kg (or less or more!). The OK benefits from comfortable side decs and 'sitting out' position with the rig, sail and controls chosen to suit the owner's physique and personal preference.

The O.K. was intended as a preparation class for the Olympic Finn and it has followed its technical evolution ever since. The rig is identical to a Finn comprising a single sail set on a rotating, un-stayed, bending mast.
OKs are built in plywood, G.R.P and composite construction and all forms enjoy equal racing success. Freedom of choice in hull materials is replicated in choice of rig. The choice of mast, sail and fitting must fit within the class rules but enables the sailor to have a combination suited to his/her requirements. Consequently, every OK develops to suit the owner's style of sailing, while the shape of the hull is designed by a comprehensive set of strict one-design rules ensuring a long competitive life span. Old boats often only need a rig up-date and minor constructional modifications to make them competitive, provided they meet modern buoyancy requirements.