Svenskt Respitsystem (SRS), formerly known as Leading Yard Stick and
Lidingö
Lidingö, also known in its definite form ''Lidingön'' and as ''Lidingölandet'', is an island in the inner Stockholm archipelago, northeast of Stockholm, Sweden. In 2010, the population of the Lidingö urban area on the island was 31,561. It is ...
Yard Stick (LYS). SRS is a semi-empirically based
handicapping system used in
yacht racing
Yacht racing is a sailing sport involving sailing yachts and larger sailboats, as distinguished from dinghy racing, which involves open boats. It is composed of multiple yachts, in direct competition, racing around a course marked by buoys or ...
in the
Nordic countries. The first version of the handicap system was developed in 1970 by the Swedish
yacht designer
Lars-Olof Norlin. He based the system on regatta results from the
Round Lidingö Race. His own design,
Allegro 27, was used as the benchmark and was by definition assigned a LYS value of 1.00.
Every yacht model has a SRS number that was previously based on results in regattas or, for new models, based on a
velocity prediction program
A velocity prediction program (VPP) is a computer program which solves for the performance of a sailing yacht in various wind conditions by balancing hull and sail forces. VPPs are used by yacht designers, boat builders, model testers, sailors ...
(VPP) as in
IMS and some other handicapping systems. The SRS number is multiplied by the measured time in order to get the handicap corrected time. Thus, a yacht with SRS 1.30 needs to sail at least 30% faster than a yacht with SRS 1.00 to win over it.
Trimarans of the type open OMRA 60, designed for racing only, have SRS values above 3.0.
The system was revised in 2011 and onwards, and is now primarily based on a secret calculation formula that should reflect the performance of each yacht. The formula is secret to prevent development of designs that are optimised for SRS racing.
As the system is semi-empirically based the SRS number for each individual model might be subject for evaluation and eventually change. This particularly applies to new models based on VPP. The system enables yachts of all sizes and types to compete with each other. SRS 1.00 would equal an average boatspeed of 5.5
knot
A knot is an intentional complication in cordage which may be practical or decorative, or both. Practical knots are classified by function, including hitches, bends, loop knots, and splices: a ''hitch'' fastens a rope to another object; a ' ...
s on a circular course at a wind speed of 5.0
m/s.
SRS numbers
The numbers are agreed on by an internordic group. The group is responsible for maintaining a standard list, and agree on SRS values for models that are not yet on the list. If there are sufficient numbers of a specific model, the model will become a standard model.
The standard list is under constant review and change, and an updated list can be found a
norlys.org
References
{{Yacht handicapping rules
Handicap (sailing)
Sailing in Sweden
1970 in sailing