An Ultra Light Displacement Boat (or ULDB) is a term used to refer to a modern form of sailboat watercraft with limited displacement relative to the hull size (waterline length). Principally manufactured from the mid 1970s through mid 1980s, these boats generally sit higher in the water allowing them to move faster in nearly all water types other than directly crashing into larger waves, upwind, where the momentum of the water slows the boat down due to their lighter weights. They are typically racer-cruiser and/or "trailer sailer" boats that are excellent for towing, due to their light weight. They typically have cabins, but are designed for racing, excellent low-wind characteristics, large sail plans, and to have decent weight of crew-members to control heeling of the boat under medium winds, and higher. While some have keel-stepped masts and are raced in oceans, ocean bays, or offshore, such as the Olson 30, most have deck-stepped masts and are typically more common inland and in lakes or limited or protected ocean environments due to the construction design of these boats, and to provide some level of comfort to the crew.
The possibility of further speed increase [...] will always attract ardent believers in their speed virtues, just as they have done in the past. The ULDB are, however, very capricious creatures in terms of performance. They may deliver the goods, provided there is just a right kind of wind and from the right direction to sail 'full and by'. And since weather is also capricious, the ULDB and weather seldom suit each other. 'Light displacement craft', Davidson remarked, 'are not new in principle'. For many centuries there have been canoes, proas and the like in the South Pacific and other places, with similar displacement in proportion to the sail area and hull length. Racing dinghies, or dinghy-like modern offshore racers, so common today, are typical examples of the same principle. In all instances the combination of the major design features: displacement, sail area, length and stability [i.e. —] power to carry sails effectively, is radically different from the combination found in the traditional seaworthy and wholesome yachts.
— C. A. Marchaj, Sail Performance (1996) [1]
ULDBs are competitive, even after 35 years with open ocean racing participation and podium finishes even today. The relative low cost to obtain, tough construction and readily easy modifications make an Olson or a Hobie an extremely competitive and fun boat. The boats do lack comfort, and are not designed for cruising; however, with multiple transpac races, and multiple Bermuda 1-2 entries, they are proving to be a stalwart competitor despite their older design.
The list of UDLBs manufactured is extensive. Here is a partial list, so far:
A yacht is a sail- or motor-propelled watercraft made for pleasure, cruising, or racing. There is no standard definition, though the term generally applies to vessels with a cabin intended for overnight use. To be termed a yacht, as opposed to a boat, such a pleasure vessel is likely to be at least 33 feet (10 m) in length and may have been judged to have good aesthetic qualities.
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.
Dinghy sailing is the activity of sailing small boats by using five essential controls:
Capsizing or keeling over occurs when a boat or ship is rolled on its side or further by wave action, instability or wind force beyond the angle of positive static stability or it is upside down in the water. The act of recovering a vessel from a capsize is called righting. Capsize may result from broaching, knockdown, loss of stability due to cargo shifting or flooding, or in high speed boats, from turning too fast.
In sailing, hiking is the action of moving the crew's body weight as far to windward (upwind) as possible, in order to decrease the extent the boat heels. By moving the crew's weight to windward, the moment of that force around the boat's center of buoyancy is increased. This opposes the heeling movement of the wind pushing sideways against the boat's sails. It is usually done by leaning over the edge of the boat as it heels. Some boats are fitted with equipment such as hiking straps and trapezes to make hiking more effective.
Hobie Cat is a company that manufactures watercraft and other products as the Hobie Cat Company. "Hobie Cat" can also refer to specific products of the company, notably its sailing catamarans. Its fiberglass catamaran models range in nominal length between 14 feet (4.3 m) and 18 feet (5.5 m). Rotomolded catamaran models range in length between 12 feet (3.7 m) and 17 feet (5.2 m). Other sailing vessels in the Hobie Cat lineup include, monocats, dinghies, and trimarans, ranging in length between 9 feet (2.7 m) and 20 feet (6.1 m). Its largest product was the Hobie 33, 33 feet (10 m) in length. The company's non-sailing product line includes surfboards, kayaks, stand-up paddle boards, pedalboards, eyeware, and e-bikes. It was founded in 1961 by Hobart (Hobie) Alter, who originally manufactured surfboards.
The International Offshore Rule (IOR) was a measurement rule for racing sailboats. The IOR evolved from the Cruising Club of America (CCA) rule for racer/cruisers and the Royal Ocean Racing Club (RORC) rule.
A boat is said to be turtling or to turn turtle when it is fully inverted. The name stems from the appearance of the upside-down boat, similar to the carapace of a sea turtle. The term can be applied to any vessel; turning turtle is less frequent but more dangerous on ships than on smaller boats. It is rarer but more hazardous for multihulls than for monohulls, because multihulls are harder to flip in both directions. Measures can be taken to prevent a capsize from becoming a turtle.
A sailing hydrofoil, hydrofoil sailboat, or hydrosail is a sailboat with wing-like foils mounted under the hull. As the craft increases its speed the hydrofoils lift the hull up and out of the water, greatly reducing wetted area, resulting in decreased drag and increased speed. A sailing hydrofoil can achieve speeds exceeding double and in some cases triple the wind speed.
Phil Morrison is a British boat designer and racer rendered notable by the success of his many designs in many classes since 1967 as well as his own distinguished yacht racing career.
The Olson 30 is a sailboat designed by George Olson of Santa Cruz, CA around 1978. Olson was a surfer and surfboard shaper who decided to design a 30' ultra light displacement boat while on a delivery from Honolulu to Santa Cruz on Merlin, a 68' Bill Lee designed and built ultralight sailboat which had competed in the biennial Transpac race in 1977. During this delivery, Olson came up with the idea while sailing with Denis Bassano and Don Snyder, who lent their initials to the prototype's name, SOB 30. The resulting boat was christened Pacific High, and it was launched in 1978.
A sailing yacht, is a leisure craft that uses sails as its primary means of propulsion. A yacht may be a sail or power vessel used for pleasure, cruising, or racing. There is no standard definition, so the term applies here to sailing vessels that have a cabin with amenities that accommodate overnight use. To be termed a "yacht", as opposed to a "boat", such a vessel is likely to be at least 33 feet (10 m) in length and have been judged to have good aesthetic qualities. Sailboats that do not accommodate overnight use or are smaller than 30 feet (9.1 m) are not universally called yachts. Sailing yachts in excess of 130 feet (40 m) are generally considered to be superyachts.
A trailer sailer is a type of sailboat that has been designed to be easily transported using a boat trailer towed by an automobile. They are generally larger than a sailing dinghy. Trailer sailers include day sailers and small cabin cruisers, suitable for living on.
The term sportsboat first appeared in the late 1980s and early 1990s to describe trailer sailers that were optimised for high performance at the expense of accommodation and ballast. The very definition of the term "sportsboat" is evolving.
The Esse 990 is a 9.9-meter-long (32-foot) racing sportboat designed by Umberto Felci and built by Josef Schuchter Sportboats of Stafa, Switzerland. The first hull was sold in 2008 and series production was begun in 2009.
The Farr 3.7 is a one-person sailing dinghy designed by Bruce Farr in 1971. The design plans are sold by the 3.7 Class Owners Association and they are built by a mix of professionals and home built by amateurs. The 3.7 Class is recognised by Yachting New Zealand as a national class and yachts are sailed in New Zealand, Australia and Great Britain. Full sets of plans have been sold worldwide to a number of individuals with greatest numbers in Germany, Japan, USA, South Korea, Poland, France, Belgium, Russia, Spain, Uruguay.
The Hobie 17 is an American catamaran that was designed by John Wake as a single-handed racer and first built in 1985.
The Capri Cyclone, also referred to as the Cyclone 13 or just the Cyclone, is an American sailing dinghy that was designed by Frank V. Butler as a one-design racer and first built in 1970.
The Olson 25 is an American trailerable sailboat that was designed by George Olson as a one design and Midget Ocean Racing Club racer-cruiser and first built in 1984.
The Santana 23 is a lightweight, 23-foot 4-inch sailboat that was designed by W. Shad Turner and manufactured by W. D. Schock Corp as a "high performance racer" and trailerable cruiser. It was first built in 1978 and remained in production through 1987, with a total of 194 units produced, though the hull was brought back in 1993 as the Santana 2023. It was produced through 1984 as the Santana 23 "D" model, commonly called the Santana 23D, with a retractable, vertical, daggerboard keel similar to racing dinghys, with a remaining 50 produced through 1987 with a traditional keel, called the Santana 23K. The hull was also used to inspire the Wavelength 24 also by Schrock, and supposedly "many other models."