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35-516: The International Measurement System (IMS) is a system of handicapping sailboats for the purpose of racing that replaced the earlier International Offshore Rule (IOR) system in the early 1990s. It is managed by the Offshore Racing Congress (ORC) . In the sailing world it is usually referred to simply as 'IMS'. IMS was the first yacht racing rule developed around the central idea of a Velocity prediction program (VPP). The VPP

70-661: A safety valve opened to release over-pressure, Herreshoff closed it so the boat could achieve its anticipated maximum speed. But a boiler exploded, fatally injuring a member of the crew. Consequently, Herreshoff lost his steam engineer's license. Herreshoff was an accomplished sailor, and was inducted into the National Sailing Hall of Fame in 2011. Two of Herreshoff's sons, Sidney Dewolf Herreshoff and Lewis Francis Herreshoff , also became yacht designers. He died on June 2, 1938, in Bristol, Rhode Island . While

105-402: A high level of quality, using craftsmen that received the highest boatbuilder wages in the state of Rhode Island. Herreshoff was noted as an innovative sailboat designer of his time. His designs ranged from the 12½ , a 16-foot (12½ foot waterline) sailboat for training the children of yachtsmen, to the 144-foot America's Cup Reliance , with a sail area of 16,000 square feet. He received

140-425: A more modern form. Handicap (sailing) Typically sailing vessel classes, including international classes , are defined by measurement rules, which categorise vessels accordingly into classes of vessels, and vessels compete within their class. Handicapping allows vessels to compete across classes, and also allows vessels and crews to compete based on performance and equipment on an equal basis, by adjusting

175-800: A private speculation. It was purchased for the United States Navy under an Act of Congress dated 3 March 1887, and entered service in July 1887, attached to the Naval Torpedo Station in Newport Rhode Island. USS Stiletto was the Navy's first torpedo boat capable of launching self-propelled torpedoes. In 1888, a serious accident occurred while Herreshoff was supervising speed trials of a 138-foot (42 m), 875-horsepower (652 kW) steamboat named Say When . After

210-656: A regularly adjusted PBH figure for each yacht and crew. In theory the PBH which is adjusted after each race gives each boat an equal chance of winning each race. The International rule, also known as the Metre rule, was created for the measuring and rating of yachts to allow different designs of yacht to race together under a handicap system. Prior to the ratification of the International rule in 1907, countries raced yachts under their own national rules and international competition

245-426: A set of measurements. It represents a very well sailed boat kept in top racing condition, that is the boat at minimum weight, good sails, fair hull. Velocity prediction program (VPP)s are used by a variety of sailing organizations to assess theoretical boat performance and then assign "handicaps" to allow boats of different styles and sizes to race against one another. The IOR and IMS handicapping rules were some of

280-423: A state or regional level. At a club level, starting from a CBH or Yardstick rating a Performance Based Handicap or PBH may be used, such as PBH . This attempts to measure the relative performance of a particular yacht and crew against other yachts and crews either of the same type of other type. Clubs will often run an event or season championship based only upon a CBH rating together with a handicap winner based upon

315-481: A theoretical yacht with a rating of 0. A yacht's handicap, or rating, is the number of seconds per mile traveled that the yacht in question should be behind the theoretical yacht. Most boats have a positive PHRF rating, but some very fast boats have a negative PHRF rating. If Boat A has a PHRF rating of 15 and Boat B has a rating of 30 and they compete on a 1-mile course, Boat A should finish approximately 15 seconds in front of Boat B. Results are adjusted for handicap by

350-492: A variety of fast, steam-powered vessels and military craft. Having started its design since 1876, The Herreshoffs built the first torpedo spar boat for the U.S. Navy. Lightning , that was purchased for experimental evaluation in 1878. In 1885, Stiletto , a wooden torpedo boat with a length of 94 feet, 31 tons of displacement and a speed of 18.2 knots was launched at the Herreshoff Manufacturing Co. as

385-535: A yacht's eligibility to race in the America's Cup from 1914 to 1937 and for this the J-class was chosen. Boats built according to the rule reached their peak in the large J-class yachts. This Rating Rule is intended to calculate a rating for yachts, which can then be used to calculate its Time Correction Factor (T.C.F.) in order to have disparate yachts racing against each other. The International Offshore Rule (IOR)

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420-848: Is the IRC rule . IRC is a system managed by the Royal Ocean Racing Club (RORC) in the United Kingdom through their dedicated Rating Office, and the Union Nationale pour la Course au Large (UNCL) in France. The ORC is a system managed by the Offshore Racing Congress . Performance Handicap Racing Fleet (PHRF) is a handicapping system used for yacht racing in North America. It allows dissimilar classes of sailboats to be raced against each other. The aim

455-470: Is to cancel out the inherent advantages and disadvantages of each class of boats, so that results reflect crew skill rather than equipment superiority. PHRF is used mainly for larger sailboats (i.e., 7 meters and above). For dinghy racing , the Portsmouth yardstick handicapping system is more likely to be used. The handicap number assigned to a class of yachts is based on the yacht's speed relative to

490-621: Is well regarded as a one-design racer/cruiser. In the 1942 the shipyard built wooden hull APc-1-class small coastal transports to support the World War II demand for ships. The Herreshoff Marine Museum preserves Herreshoff's legacy at the former site of the Herreshoff Manufacturing Co. In the last quarter of the 19th century, Herreshoff constructed a double-hulled sailing boat of his own design (US Pat. No. 189,459). The craft, Amaryllis , raced at her maiden regatta on June 22, 1876, and performed exceedingly well. Her debut demonstrated

525-720: The British Thames Measurement by the Yacht Club de France in 1870 may mark the beginning of international rating rules. In 1893, the Germano-Scandinavian Union was formed and it developed its "Union Rule". Starting in 1902, under the leadership of the New York Yacht Club , U.S. yacht clubs agreed to a Universal Rule in 1905 which was based on a formula developed by Nathanael Herreshoff . The Universal Rule determined

560-635: The French fresh-water racing yacht Vendenesse , which had been described in a New York Times article and caught the attention of the Vanderbilt Americacup syndicate. In salt water, Defender was subject to galvanic corrosion , which limited its durability in water. Defender won the America's Cup in 1895 over Lord Dunraven's Valkyrie III , and she was used as an effective trial-horse for Herreshoff's new Cup defender Columbia in 1899. She

595-639: The Herreshoff Manufacturing Company's early work centered on steam-powered vessels, by the 1890s the Herreshoffs turned to the design and construction of yachts for wealthy American clients, including Jay Gould , William Randolph Hearst , John Pierpont Morgan , Cornelius Vanderbilt III , Harold Stirling Vanderbilt , William Kissam Vanderbilt II , Harry Payne Whitney and Alexander Smith Cochran . Herreshoff boat production incorporated power tools that increased productivity at

630-541: The IOR rule. IMS is generally believed to have made significant leaps of progress forward from the IOR rule it displaced in terms of fairness and accuracy. IMS racing declined seriously in the early 2000s. A raft of new technology developments in yacht design led to a situation where the very largest and most expensive yachts were able to gain a significant technology advantage which the rule was less able to account for. Smaller yacht owners began to feel unfairly disadvantaged under

665-488: The distinct performance advantages afforded by catamarans over the standard monohulls. In 1892 he build Wee Win a ½ rater for Winifred Sutton, daughter of Sir Richard Sutton, 5th Baronet , whose yacht Genesta had been beaten in the 1885 America's cup by Puritan. Wee Win was very successful racing on the Solent, leading to several follow-up orders from British Yachtswomen and Yachtsmen. Herreshoff designed and built

700-424: The earliest adopters of VPPs. Nathanael Herreshoff Nathanael Greene Herreshoff (March 18, 1848 – June 2, 1938) was an American naval architect , mechanical engineer , and yacht design innovator. He produced a succession of undefeated America's Cup defenders between 1893 and 1920. Herreshoff was born on March 18, 1848, in Bristol, Rhode Island and was named after General Nathanael Greene . He

735-529: The exhibition's machinery. In 1878 Herreshoff returned to Bristol where he and one of his brothers, John Brown Herreshoff (1841–1915), who was blind, formed the Herreshoff Manufacturing Company. Nathanael provided the engineering expertise and John provided the business expertise, managing the firm's personnel and interacting with clients. Together, they grew the business from about 20 employees to over 400. Herreshoff's talent for innovation found expression in both design and light-construction techniques. They built

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770-524: The first US patent for a sailing catamaran . The firm built the America's Cup winning Cup yachts Enterprise (1930), and Rainbow (1934), designed by Starling Burgess . Every winning America's Cup Yacht from 1893 to 1934 was built by the Herreshoff yard. The 123-foot Defender featured steel -framing, bronze plating up to the waterline and aluminum topsides to achieve a lighter and faster boat. This combination of materials had been pioneered in

805-535: The handicap number, called an IOR rating , in feet. The higher the rating, the faster the boat was deemed to be able to sail. The IOR was superseded by the International Measurement System (IMS), now updated as Offshore Racing Congress Rule (ORC) and International Rating Certificate (IRC). While some yachts race at club level under ORC or IRC in more or less their original form, others had major surgery to make them competitive within

840-476: The measurement rules to enable a design to get a better rating. Whilst this encouraged designers it discouraged owners from participating in handicap racing because designs were being outdated almost before the yacht was launched. In order to restore the equilibrium, work began on new formulas, which resulted, in the Thames Measurement which was the first formula defined for yachts. The adoption of

875-606: The new rules. In the United States, the most common handicapping rule is the PHRF rule , developed and promoted by the United States Sailing Association . While most other rules do not take past performance into account, PHRF differentiates itself by allowing skippers to request handicap reductions after a series of poor racing results. In Europe, the most common handicapping system used today

910-719: The race committee after all competitors have finished. Each region has its own variation on PHRF rules and ratings, based on local conditions. In some countries a Performance Handicap Racing Fleet (PHRF) may be used to rate trailer sailers, such as in NZ and in the USA and Canada . Rather than a vessel measurement rule, Yardstick as in Portsmouth Yardstick is used in the UK is a way of rating different classes of trailer yachts relative to each other. These are adjusted annually at

945-405: The race outcome data, to declare a handicap (adjusted) winner as distinct from a line honours (first over the finish line) winner. During the early part of the 19th century interest in yacht racing had achieved sufficient momentum to need an agreed handicapping system to allow different types of yacht to race on an equitable basis. The method of measuring merchant sailing ships carried over into

980-468: The results of numerous races each Class was allocated a distance allowance that the Class had to give away to the next lower Class. This was equivalent to a Class 1 having to sail more distance than a Class 4 yacht during a race. In 1834 handicapping by distance was changed to handicapping by time. As yacht racing in particular became more and more popular designers started to look for and found loopholes in

1015-456: The rule and between 2003 and 2007 much handicap racing around the world changed to using the newer IRC rule. However, an improved, revised version of IMS was developed over the years 2006-2008, and known as the Offshore Racing Congress (ORC) rule. As of 2008 some major sailing clubs around the world considered replacing IRC with ORC in their club activities, heralding a return to the IMS system in

1050-451: The world of yacht racing so that a yacht also now had a measured tonnage which allowed size comparisons and hence performance comparisons to be made between yachts on the basis that a properly designed big yacht will sail faster than a properly designed small yacht. Each yacht fell within a Class based upon its measured tonnage. In the early 19th century four ranges of tonnage and hence four Classes were defined. Based on experience gained from

1085-489: Was a complex computer program that integrated continuous hullform information in order to predict a given boat's speed potential in a given wind velocity. Details on the VPP were openly available to the yachting community, in contrast to the earlier IOR system. Designers and boat owners much preferred this as they were able to design new yachts to maximise performance under the rule with a degree of certainty they had not enjoyed under

International Measurement System - Misplaced Pages Continue

1120-593: 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. The IOR concentrated on hull shape with length, beam, freeboard and girth measurements, foretriangle, mast and boom measurements, and stability with an inclination test. Additionally, the IOR identified features which were dangerous, or it couldn't fairly rate, and penalized or prohibited them. The measurements and penalties were used to compute

1155-585: Was always subject to various forms of subjective handicapping. Class Based Handicap (CBH) measurement system is used, for example, for trailer sailers, such as in Australia and also in New Zealand. In Australia, the CBH system is a nationally governed handicap designed to assess the potential speed of the boat. It does not take into account the experience of the crew. Vessels are given a rating number based on

1190-535: Was broken up in 1901. Those of the 2,000-plus designs by Herreshoff that survive are sought by connoisseurs of classic yachts. Herreshoff S-Class sailboats, designed in 1919 and built until 1941, are still actively raced in Narragansett Bay , Buzzards Bay and Western Long Island Sound ( Larchmont, New York ). His 12½ design of 1914 is still being built and raced in New England as well. The New York 30

1225-823: Was one of seven brothers. He graduated from the Massachusetts Institute of Technology in 1870 with a three-year degree in mechanical engineering . After graduation, he took a position with the Corliss Steam Engine Company in Providence, Rhode Island . At the 1876 Centennial Exposition in Philadelphia, Pennsylvania , he oversaw operation of the Corliss Stationary Engine, a 40-foot-tall (12 m), 1,400-horsepower (1,000 kW) dynamo that powered

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