The Impulse 21, also called the Impulse Eagle, is an American trailerable

sailboat A sailboat or sailing boat is a boat propelled partly or entirely by sails and is smaller than a sailing ship. Distinctions in what constitutes a sailing boat and ship vary by region and maritime culture. Types Although sailboat terminology ...

that was designed by William E. Cook as a one-design racer and

day sailer A daysailer, day sailer, or dayboat is a small sailboat with or without sleeping accommodations but which is larger than a dinghy. Dayboats can be mono hull or multihull, and are typically trailer-able. Many dayboats have a small cabin or "cu ...

, It was first built in 1986.Sherwood, Richard M.: ''A Field Guide to Sailboats of North America, Second Edition'', pages 110-111.

Houghton Mifflin Company Houghton Mifflin Harcourt (; HMH) is an American publisher of textbooks, instructional technology materials, assessments, reference works, and fiction and non-fiction for both young readers and adults. The company is based in the Boston Financ ...

, 1994.

Production

The design was initially built by Impulse Marine in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

. 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.

Design

The Impulse 21 is a recreational

keelboat A keelboat is a riverine cargo-capable working boat, or a small- to mid-sized recreational sailing yacht. The boats in the first category have shallow structural keels, and are nearly flat-bottomed and often used leeboards if forced in open wat ...

, built predominantly of

fiberglass Fiberglass (American English) or fibreglass (Commonwealth English) is a common type of fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened into a sheet called a chopped strand mat, or woven into glass cloth ...

, with a Klegecell core. It has a fractional

sloop A sloop is a sailboat with a single mast typically having only one headsail in front of the mast and one mainsail aft of (behind) the mast. Such an arrangement is called a fore-and-aft rig, and can be rigged as a Bermuda rig with triangular sa ...

rig, a

raked stem The stem is the most forward part of a boat or ship's bow and is an extension of the keel itself. It is often found on wooden boats or ships, but not exclusively. Description The stem is the curved edge stretching from the keel below, up to ...

, a cut-out, walk-through, sharply

reverse transom A transom is the vertical reinforcement which strengthens the stern of a boat. This flat termination of the stern is typically above the waterline. The term was used as far back as Middle English in the 1300s, having come from Latin ''transvers ...

that allows ease of boarding, an internally mounted spade-type

rudder A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, aircraft, or other vehicle that moves through a fluid medium (generally aircraft, air or watercraft, water). On an aircraft the rudder is used primarily to ...

controlled by a

tiller A tiller or till is a lever used to steer a vehicle. The mechanism is primarily used in watercraft, where it is attached to an outboard motor, rudder post or stock to provide leverage in the form of torque for the helmsman to turn the rudder. ...

and a fixed fin

keel The keel is the bottom-most longitudinal structural element on a vessel. On some sailboats, it may have a hydrodynamic and counterbalancing purpose, as well. As the laying down of the keel is the initial step in the construction of a ship, in Br ...

. It displaces and carries of ballast. The boat has a draft of with the standard keel. The design has only a small

cuddy cabin A cuddy is a small room or cupboard, particularly on a boat. Sometimes a cuddy refers to a small but cosy hut. The origin of the term is not clear. Cuddy was in use in colonial America as early as 1655. The term may derive from the Dutch ''kaj ...

for sail and

cooler A cooler, portable ice chest, ice box, cool box, chilly bin (in New Zealand), or esky (Australia) is an insulated box used to keep food or drink cool. Ice cubes are most commonly placed in it to help the contents inside stay cool. Ice packs ar ...

stowage and no sleeping accommodation. For sailing the design is equipped with a cockpit that is long. It has a launcher tube for a

spinnaker A spinnaker is a sail designed specifically for sailing off the wind on courses between a reach (wind at 90° to the course) to downwind (course in the same direction as the wind). Spinnakers are constructed of lightweight fabric, usually n ...

of and a self-tacking

jib A jib is a triangular sail that sets ahead of the foremast of a sailing vessel. Its tack is fixed to the bowsprit, to the bows, or to the deck between the bowsprit and the foremost mast. Jibs and spinnakers are the two main types of headsails ...

. The boat is equipped with foam-fill compartments for buoyancy. The design has a

Portsmouth Yardstick The Portsmouth Yardstick (PY) or Portsmouth handicap scheme is a term used for a number of related systems of empirical handicapping used primarily in small sailboat racing. The handicap is applied to the time taken to sail any course, and the han ...

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."

References

{{Trailer sailers and Trailer yachts worldwide Keelboats 1980s sailboat type designs Sailing yachts Trailer sailers Sailboat type designs by William E. Cook Sailboat types built by Impulse Marine Sailboat types built by Johnson Boat Works

Production

Design

Operational history

See also

References