International Viper 640 Class Association




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One-Design Class Type: Keelboat

Was this boat built to be sailed by youth or adults? Both

Approximately how many class members do you have? 325

About International Viper 640 Class Association

“It’s a perfect balance of dinghy and keelboat”
The Viper 640 is a two to four person, high-performance sports boat. It is FUN, FAST, EASY and AFFORDABLE. The Viper makes high-performance sailing available to everyone. The open transom bails water instantly, even in extreme conditions. The Viper is simple, clean, and comfortable, with no protruding hardware and everything placed for efficiency.

The Viper is light enough to be towed behind a compact car and simple enough to be rigged and sailed in under a half hour. The boat can be launched from a hoist or ramp.

The 640 is strict one-design with no changes permitted to the boat as supplied by the class approved builder. The only option is sails, supplied by class approved sailmakers and strictly controlled through class rules, which encourages the development of tuning techniques with the help of the best sailors and sailmakers.


Boats Produced: 325

Class boat builder(s):

Rondar Race Boats (
Paul Young, President

Approximately how many boats are in the USA/North America? 270

Where is your One-Design class typically sailed in the USA? List regions of the country:

Northeast/Marblehead, Long Island Sound, Annapolis, Lake Champlain, Ottawa, Sarnia (ON), Gulf Sailing Association, Long Beach (CA), Santa Barbara (CA), Anacortes (WA)

Does this class have a spinnaker or gennaker? Yes

Ideal combined weight of range of crew:  500-600 lbs.

Portsmouth Yardstick Rating:  70.4 (U.S.)

Boat Designed in 1996

Beam: 8′ 2″

Weight of rigged boat without sails: 749

Draft: 4′ 6″

Mast Height: