The theoretical maximum speed that a displacement hull can move efficiently through the water is determined by it's waterline length and displacement. It may be unable to reach this speed if the boat is underpowered or heavily loaded, though it may exceed this speed given enough power. Read more.
Classic hull speed formula:
Hull Speed = 1.34 x √LWLA more accurate formula devised by Dave Gerr in The Propeller Handbook replaces the Speed/Length ratio constant of 1.34 with a calculation based on the Displacement/Length ratio.
Max Speed/Length ratio = 8.26 ÷ Displacement/Length ratio.311
Hull Speed = Max Speed/Length ratio x √LWL
A measure of the power of the sails relative to the weight of the boat. The higher the number, the higher the performance, but the harder the boat will be to handle. This ratio is a "non-dimensional" value that facilitates comparisons between boats of different types and sizes. Read more.
SA/D = SA ÷ (D ÷ 64)2/3
A measure of the stability of a boat's hull that suggests how well a monohull will stand up to its sails. The ballast displacement ratio indicates how much of the weight of a boat is placed for maximum stability against capsizing and is an indicator of stiffness and resistance to capsize.
Ballast / Displacement * 100
A measure of the weight of the boat relative to it's length at the waterline. The higher a boat’s D/L ratio, the more easily it will carry a load and the more comfortable its motion will be. The lower a boat's ratio is, the less power it takes to drive the boat to its nominal hull speed or beyond. Read more.
D/L = (D ÷ 2240) ÷ (0.01 x LWL)³
This ratio assess how quickly and abruptly a boat’s hull reacts to waves in a significant seaway, these being the elements of a boat’s motion most likely to cause seasickness. Read more.
Comfort ratio = D ÷ (.65 x (.7 LWL + .3 LOA) x Beam1.33)
This formula attempts to indicate whether a given boat might be too wide and light to readily right itself after being overturned in extreme conditions. Read more.
CSV = Beam ÷ ³√(D / 64)
In 1959 Carl Alberg was commissioned by Pearson Yachts to design a 22-foot cruiser suitable for racing in the Midget Ocean Racing Club (MORC). This was the ELECTRA, which had a masthead rig, a small, self-bailing cockpit, and a cabin with galley space, head and bunks. About 350 ELECTRAS were built over the next six years.
Pearson dealers surmised that prospective Electra buyers might prefer the boat with a larger cockpit and smaller cabin. They passed the information along to Pearson, who subsequently asked Alberg to design a day sailor, suitable for one-design racing, based on the ELECTRA hull.
Other changes made included moving the mast six inches s forward, increasing the area of the mainsail, and reducing the height of the fore triangle.
The ELECTRA DAY SAILOR, as it was first called, was an instant success: 219 were sold in the first year (1962). At this time, the first class racing was organized (Fleet #l, out of Larchmont, New York).
The next year saw 213 more boats built and nine more fleets formed - in Houston, Texas; Hingham, Massachusetts; Providence, Rhode Island; Huntington and Port Washington, New York, Miami, Florida; Gibson Island, Maryland; and Falmouth, Maine.
The last known builder (2003) was Ensign Spars Inc. of Dunedin, FL (USA).
Great choice! Your favorites are temporarily saved for this session. Sign in to save them permanently, access them on any device, and receive relevant alerts.