The purpose of the Small Catamaran Handicap Rating System (SCHRS) is to provide a rating formula whereby a wide range of beach catamarans may be scored against each other as fairly as possible.
It is intended to be objective, transparent and inclusive, where possible, of catamarans that can be measured, and relieve event organisers from the burden of measuring boats. The closest approximation to perfection is most likely to be achieved over a normal range of weather conditions between similar boats.
That is the goal which SCHRS, as an officially-recognised rating system of the International Sailing Federation (ISAF) for beach catamarans, strives to achieve.
Handicapping systems can be based purely upon measurements entered into a formula, or purely on empirical evidence, or more usually a mixture of both:
Measurement Systems: Boats are measured according to a list of criteria e.g. sail area, length, weight. These are multiplied by various constants. Then those individual components are combined into a formula.
- Advantages: New boats can be quickly adopted. Manufacturers understand how new boats will be rated before production costs are committed. Established classes with suitable class rules, can have "type approval" after suitable measurement of a number of boats to ensure consistency of manufacturer.
- Disadvantages: Boats must be formally measured. The rules need to be simple enough to be understood, yet complex enough to provide fair ratings.
Performance Systems: A database of racing results is collected from sailing clubs and averages are calculated from these.
- Advantages: No need to measure boats
- Disadvantages: The rating includes the skill of the sailors. This may introduce bias in as far as inexperienced sailors tend to buy older designs second-hand. The database may not be large enough to be statistically significant for many classes of boat, let alone any new innovation. The returns need to be for unadjusted times, not final positions.
Our position is that the best resolution is to use a measurement formula and review that in the light of developments within beach catamaran design. Catamarans are also easier to rate using formula based methods due to their inherent geometric similarity. Accordingly over the years it has been modified to take into account single-handers, dagger-boards, asymmetric spinnakers and most recently, righting moment.
Sailing events require economies of scale, whether these are local club races, one-design class regattas or open long distance events.
Local clubs require a handicap system to manage small numbers of very varied boats, one-design classes require a handicap system to become established and open long distance events require a handicap system to attract the numbers that finance the substantial support teams required.
In practice this creates two principal user groups:
- Local clubs: These often race older designs, bought second-hand by first-time buyers. Fortunately, the design of the modern fibreglass catamaran is such that age and intense use do not significantly degrade its hulls, so older boats provide good sailing even if they are technologically out-dated. If enthused by fair racing, those sailors may graduate to other classes and attend open events.
- Open Events: These high-profile occasions attract a range of classes and some innovative designs. If provided with such marketing show-cases, these new entrants may succeed in becoming established one-design classes, so attracting new participants to our sport.
Our position is that the objective is to cater for both types of user - providing that the boats can be measured according to the formula - as both are essential for the health of our sport and as it is the intention of SCHRS to be inclusive.
The key condition for admission is a measurement certificate, approved by a measurer who is officially recognised by a national sailing authority or a class association.
The SCHRS Formula can be obtained by anyone from the SCHRS website. This allows people to do "what if" calculations and also to give an indication of a rating should they choose to change an item such as a sail. In order to get an official SCHRS rating, the boat is formally measured by an accredited measurer and then a rating is then calculated and an official certificate produced. The rating will also be added to the SCHRS database and displayed on the site with a suitable classification.
There are alternative routes to achieving certification:
- Class Rules: If these are drawn sufficiently tightly, in that they specify all the factors required in the formula, then these are acceptable. Where tolerances are permitted, SCHRS will take "best practice" based on the most widely used variant at the top of the fleet. This is a pragmatic approach requiring some judgement.
- Type-Approved Class Certificate: A sample of standard boats may be officially measured at random. This is likely to be the means for rating mass market classes. If the builder can only provide new boats, then the certification is subject to subsequent review.
- Individual Certification: Classes of boats where the class rules do not control the appropriate items to allow SCHRS to grant type approval, one-off, experimental and new designs require individual certificates. If these designs contain features with which the formula is not intended to cope then the boat cannot be certified, unless it is raced in a version that excludes these features. Where possible, the formula may subsequently be modified to incorporate such features. If a standard boat is raced with a non-standard modification, e.g. extra trapeze, spinnaker, class-illegal sails, then the entire boat requires an individual certificate. Individual certificates should only qualify a boat for the Open class of an event.
- Provisional Rating: Where it may not be economically viable to obtain certification for some out-of-production designs, a provisional rating may be calculated based on un-certified data. Where such ratings are all that is available, they will be indicated as such in the SCHRS ratings table. Organisers should specify whether their event include or exclude "Provisionally Rated" boats.
At present there are three main systems for rating small catamarans, each established in different parts of the world. All try to achieve similar objectives but each has its strengths and weaknesses.
SCHRS: Its strength is the transparency and objectivity of its accessible measurement formula, which enables any measureable catamaran to be included in an event and can theoretically be adapted for other purposes. Its weakness is that boats must be measured. It dominates in France and the UK, and is also used in Southern Africa and experimentally in the US.
Texel: This is also a measurement formula. Its strength is that it is more responsive to changes in actual performance based on its unique statistical database of results. Its weakness is that this database reflects the unique characteristics of one particular event. It is used in the Netherlands, Germany and neighbouring countries.
Portsmouth Yardstick (PY): This is a performance measurement system. Its strength is that it enables mono- and multi-hulls to compete and in the US that it includes a wind-strength adjustment factor. Its weaknesses are firstly that it also adjusts for the crew skill factor and secondly that the data may not be statistically significant for many classes. It has fallen into disuse for catamarans in the UK, but is still used in the US and as the Victoria Yardstick, also in Australia.
It is our objective to work towards closer co-operation between all rating systems, exchanging knowledge and experience. This will reduce the scope for rating arbitrage, improve each system and reduce administrative costs.
A first step has been taken with the spread of PY Look Alike ratings in the UK. This involves taking a statistical best fit approach using the catamarans for which we have both SCHRS and PY ratings (e.g. Dart 18, Hurricane 5.9). The SCHRS rating is multiplied by the resultant conversion factor to generate a PY rating for the many catamarans on the SCHRS list but not PY.
We are also sharing experience with the Texel and Victoria rating systems, to ensure that SCHRS draws on the best knowledge available worldwide.