Impulse 21

Impulse 21

I21
Development
Designer	William E. Cook
Location	United States
Year	1986
No. built	150
Builder(s)	Impulse Marine Johnson Boatworks
Role	Day sailer-One-design racer
Name	Impulse 21
Boat
Displacement	1,300 lb (590 kg)
Draft	3.25 ft (0.99 m)
Hull
Type	monohull
Construction	fiberglass
LOA	21.00 ft (6.40 m)
LWL	18.50 ft (5.64 m)
Beam	8.00 ft (2.44 m)
Hull appendages
Keel/board type	fin keel
Ballast	600 lb (272 kg)
Rudder(s)	internally-mounted spade-type rudder
Rig
Rig type	Bermuda rig
I foretriangle height	23.10 ft (7.04 m)
J foretriangle base	7.00 ft (2.13 m)
P mainsail luff	26.00 ft (7.92 m)
E mainsail foot	9.70 ft (2.96 m)
Sails
Sailplan	fractional rigged sloop
Mainsail area	126.10 sq ft (11.715 m2)
Jib/genoa area	80.85 sq ft (7.511 m2)
Spinnaker area	340 sq ft (32 m2)
Total sail area	206.95 sq ft (19.226 m2)
Racing
D-PN	183

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. ^{[1] [2] [3] [4] [5]}

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. ^{[1] [3] [4] [6]}

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 1,300 lb (590 kg) and carries 600 lb (272 kg) of ballast. ^{[1] [3]}

The boat has a draft of 3.25 ft (0.99 m) with the standard keel. ^[1]

The design has only a small cuddy cabin for sail and cooler stowage and no sleeping accommodation. ^[3]

For sailing the design is equipped with a cockpit that is 9 ft (2.7 m) long. It has a launcher tube for a spinnaker of 340 sq ft (32 m²) and a self-tacking jib. The boat is equipped with foam-fill compartments for buoyancy. ^[3]

The design has a Portsmouth Yardstick D-PN racing average handicap of 183. ^[3]

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." ^[3]

See also

• List of sailing boat types
• Impulse (dinghy), another sailboat design with the same name.

References

1. McArthur, Bruce (2020). "Impulse 21 sailboat". sailboatdata.com. Archived from the original on 14 November 2020. Retrieved 14 November 2020.
2. McArthur, Bruce (2020). "William Cook". sailboatdata.com. Archived from the original on 14 November 2020. Retrieved 14 November 2020.
3. 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
4. "Impulse 21 Owners & Sailors". Yahoo Groups . Archived from the original on 25 October 2020. Retrieved 14 November 2020.
5. US Sailing (2023). "Impulse 21". ussailing.org. Archived from the original on 22 January 2023. Retrieved 22 January 2023.
6. McArthur, Bruce (2020). "Johnson Boat Works (USA) 1896 - 1998". sailboatdata.com. Archived from the original on 8 September 2020. Retrieved 14 November 2020.