Surveying (regatta sailing)

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Measurement and measurement certificate
In order for a sailing boat to take part in a regatta , the owner / helmsman must be able to present a valid measurement certificate . The measurement certificate certifies the conformity to a boat class . The prerequisite for receiving a measurement certificate is the measurement of the boat in question by a surveyor appointed by the German Sailing Association (or another official sailing association) . The owner bears the costs of the measurement.

How and what is measured

the essential dimensions that are measured when sailing
Neck of a headsail with the remains of a surveying stamp (left)
Sail measurement
In sailing either individual measurements are taken ( luff , Unterliekslänge , or the so-called. LP-dimension , ie the height of the sail to the luff) or it is simply determined the area, depending on the class rules. After the measurement, sails receive a stamp in the area of ​​the neck with the measured values ​​and the signature of the surveyor. They can usually also be measured by the sailmaker , most sailmakers are authorized to do so by the DSV . In larger regattas, such as national and international championships , it is also common for the race committee to subject the boats to a control measurement. In each case, the dimensions of the sails, often also the boat weight ( displacement ), are checked.
Water measurement
For yachts, in addition to the so-called land measurement (measurement of the boat hull on land), a water measurement is also necessary. For example, the exact swimming position as well as the waterline length and width are measured, and the stability , i.e. the resistance to artificial heeling , is often determined. For the water measurement it is stipulated exactly which objects are allowed to be on board ( e.g. anchor , engine) and which are not, or in which condition the liquid tanks (fresh water, waste water, diesel) must be.
Land surveying
When surveying the land, the boat hull and rigging are measured. This is ideally done in a closed hall on a level surface. The mast and main boom receive so-called measuring marks , markings on the mast top and on the aft end of the main boom, which indicate the maximum dimension of the main sail for everyone to see. In contrast to the sails, the measurement of the hull and rig cannot be carried out by the shipyard. However, there is the option of doing without the hull measurement for series boats if the shipyard can prove the uniformity (one design) of the boats and the rigging.
Measurement of individual buildings and prototypes
Individual buildings and prototypes must always be subjected to a complete measurement.

Survey mode

There are three different measurement modes:

Measurement in unit classes
In the case of unit classes, the surveyor checks whether the boat was built in accordance with the designer's drawings. In addition, the boat must fully comply with the provisions of the Class Rules i. d. Usually in written form. Among other things
  • the geometry of the boat hull is checked by applying calibrated templates ,
  • check the wall thickness of the boat hull or the planking ,
  • Measure the rigging and sails according to the information in the construction drawings,
  • the weight ( displacement ) is determined by a suitable scale,
  • all other information in the class regulations checked visually and by measuring.
Measurement in construction classes
The measurement of boats of a construction class is often very easy, as these classes only prescribe the main dimensions (length, sail area, weight, ...) and everything else is optional.
Some classes also have so-called measurement formulas (see, for example, meter class and meter formula ). The survey , which is then carried out in two steps as land survey and water survey (swimming position, heeling tests, ...) is correspondingly more complex .
Measurement in compensation classes
Compensation boats often have very complicated measurement procedures, whereby a boat is given a racing value (rating) . In regattas , the time sailed is multiplied by a time correction factor (derived from the race value) in order to determine the relevant calculated time for the classification (see compensation classes ).
  • ORC International survey
The currently used measurement formula in ocean sailing, a further development of the IMS (International Measurement System) , is a complex scientific measurement system for regatta yachts. The speed potential of a boat is determined very precisely, for example by completely recording the hull geometry, as well as all swimming positions in connection with the respective wetted surface (= friction surface between the hull outer skin and water) , the stability (heeling tests) and of course the rigging and sail dimensions. ORC-I is based on a velocity prediction program (VPP). For this purpose, several correction factors are assigned to each boat on the basis of the measurement. For the first time, this also enables the wind force to be taken into account for the classification, which distinguishes IMS from all previous measurement methods. The VPP is constantly being developed and adapted to the latest findings. An ORC-I measurement takes approx. 10-15 hours. ORC-I is the most widely used surveying system in Germany and Northern Europe. The formula of ORC-I is open, so it can be viewed by anyone, so that boats can be optimized for the formula (it can be advantageous to make a boat a little slower if this is overcompensated by a better handicap value).
  • IRC
The IRC system is similar to the ORC-International, the boats are also painstakingly measured for IRC and a racing value is calculated from the data obtained. The big difference, however, is that IRC's speed prediction program (VPP) is not public. This makes it more difficult to optimize a boat for a cheap racing value. The idea behind this is that owners and designers should not try to build so-called "formula pigs", but rather fast, seaworthy boats in the hope that they will also get a realistic racing value. The disadvantage of secret VPPs, however, is that their accuracy cannot be verified by the public.
IRC is the predominant system in the English-speaking sailing nations (Great Britain, USA, Australia and New Zealand) as well as in the Mediterranean.
  • ORC Club
ORC Club is a simplified surveying system based on ORC-International and is intended for the implementation of club regattas. High-level regattas cannot be sailed with it because of the lower accuracy.
  • Yardstick rating
In the yardstick rating , a boat is not measured, but its speed potential is determined empirically. New boats are given a preliminary yardstick number until enough regatta results are available to enable a more precise assessment. Measured boats can of course also take part in yardstick regattas. Yardstick numbers have now been established for almost every boat class and thus almost every measured boat.

See also

Web links