Impulse 21
{{short description|Sailboat class}}
{{Use dmy dates|date=November 2020}}
{{Use American English|date=November 2020}}
{{Infobox sailboat specifications
|name = Impulse 21
|insignia =
I21
|insignia size = 150px
|insignia alt =
|insignia caption =
|line drawing =
|line size =
|line alt =
|line caption =
|image boat =
|image size =
|image alt =
|image caption =
|designer = William E. Cook
|architect =
|location = United States
|year = 1986
|no built = 150
|design =
|class =
|brand =
|builder = Impulse Marine
Johnson Boatworks
|role = Day sailer-One-design racer
|boats =
|crew =
|trapeze =
|draft = {{convert|3.25|ft|m|abbr=on}}
|air draft =
|displacement = {{convert|1300|lb|kg|0|abbr=on}}
|hulls =
|hull type = monohull
|construction = fiberglass
|loa = {{convert|21.00|ft|m|abbr=on}}
|loh =
|lwl = {{convert|18.50|ft|m|abbr=on}}
|beam = {{convert|8.00|ft|m|abbr=on}}
|hull draft =
|hull weight =
|engine =
|appendages =
|keel type = fin keel
|ballast = {{convert|600|lb|kg|0|abbr=on}}
|rudder type = internally-mounted spade-type rudder
|rigs =
|rig type = Bermuda rig
|I = {{convert|23.10|ft|m|abbr=on}}
|J = {{convert|7.00|ft|m|abbr=on}}
|P = {{convert|26.00|ft|m|abbr=on}}
|E = {{convert|9.70|ft|m|abbr=on}}
|mast length =
|rig other =
|sails =
|sailplan = fractional rigged sloop
|sailarea main = {{convert|126.10|sqft|m2|abbr=on}}
|sailarea headsail = {{convert|80.85|sqft|m2|abbr=on}}
|sailarea spin = {{convert|340|sqft|m2|abbr=on}}
|sailarea gen =
|sails other =
|sailarea upwind =
|sailarea downwind =
|sailarea total = {{convert|206.95|sqft|m2|abbr=on}}
|rating =
|d-pn = 183
|rya-pn =
|phrf =
|status =
|previous =
|successor =
}}
The Impulse 21, built by Impulse Marine Inc is an American trailerable sailboat that was designed by William E. Cook as a one-design racer and day sailer, It was first built in 1986.{{cite web|url= https://sailboatdata.com/sailboat/impulse-21|title= Impulse 21 sailboat|access-date= 14 November 2020|last= McArthur|first= Bruce|work= sailboatdata.com|year= 2020|archive-url= https://archive.today/20201114155633/https://sailboatdata.com/sailboat/impulse-21|archive-date= 14 November 2020|url-status= live}}{{cite web|url= https://sailboatdata.com/designer/cook-william|title= William Cook|access-date = 14 November 2020|last= McArthur| first = Bruce |work = sailboatdata.com|year = 2020|archive-url= https://archive.today/20201114155620/https://sailboatdata.com/designer/cook-william|archive-date= 14 November 2020 |url-status= live}}Sherwood, Richard M.: A Field Guide to Sailboats of North America, Second Edition, pages 110-111. Houghton Mifflin Company, 1994. {{ISBN|0-395-65239-1}}{{cite web|url= https://groups.yahoo.com/neo/groups/Impulse21sailors/info|title= Impulse 21 Owners & Sailors|access-date= 14 November 2020|work= Yahoo Groups|archive-url= https://web.archive.org/web/20201025133553/https://groups.yahoo.com/neo/groups/Impulse21sailors/info|archive-date= 25 October 2020|url-status= dead}}{{cite web|url= https://www.ussailing.org/one-design-profile/impulse-21/|title= Impulse 21|access-date= 22 January 2023|author= US Sailing|author-link= US Sailing |work= ussailing.org|year= 2023|archive-url= https://archive.today/20230122170921/https://www.ussailing.org/one-design-profile/impulse-21/|archive-date= 22 January 2023|url-status= live}}
Production
The design was initially built by Impulse Marine in the United States. After the first 10-12 boats were completed, it was then built under contract by Johnson Boatworks on behalf of Impulse Marine. A total of 150 boats were completed, but it is now out of production.{{cite web|url = https://sailboatdata.com/builder/johnson-boat-works-usa|title = Johnson Boat Works (USA) 1896 - 1998|access-date = 14 November 2020|last = McArthur|first = Bruce|work = sailboatdata.com|year = 2020|archive-url = https://archive.today/20200908225439/https://sailboatdata.com/builder/johnson-boat-works-usa|archive-date = 8 September 2020|url-status = live}}
Design
The Impulse 21 is a recreational keelboat, built predominantly of fiberglass, with a Klegecell core. It has a fractional sloop rig, a raked stem, a cut-out, walk-through, sharply reverse transom that allows ease of boarding, an internally mounted spade-type rudder controlled by a tiller and a fixed fin keel. It displaces {{convert|1300|lb|kg|0|abbr=on}} and carries {{convert|600|lb|kg|0|abbr=on}} of ballast.
The boat has a draft of {{convert|3.25|ft|m|abbr=on}} with the standard keel.
The design has only a small cuddy cabin for sail and cooler stowage and no sleeping accommodation.
For sailing the design is equipped with a cockpit that is {{convert|9|ft|m|abbr=on}} long. It has a launcher tube for a spinnaker of {{convert|340|sqft|m2|abbr=on}} and a self-tacking jib. The boat is equipped with foam-fill compartments for buoyancy.
The design has a Portsmouth Yardstick D-PN racing average handicap of 183.
Operational history
In a 1994 review Richard Sherwood wrote, "a day sailer with room for lots of crew, the Impulse's most unusual feature is a center console housing the control lines for the jib sheet, jib traveler, jib Cunningham, main Cunningham, boom vang, spinnaker halyard, spinnaker retriever, and backstay adjustments. The cockpit is 9 feet long, with seating on the wide decks ... Keel depth is moderate, so that Impulse may be trailered. However, the keel, taken with the wide beam and deck, provides good stability, and foam-filled compartments provide flotation."
See also
- List of sailing boat types
- Impulse (dinghy), another sailboat design with the same name.
References
{{Reflist}}
{{Trailer sailers and Trailer yachts worldwide}}
Category:1980s sailboat type designs
Category:Sailboat type designs by William E. Cook