CompetitorsThe ISC Rating System

The ISCRS is a free rating system for competitors, without current IRC rating certificates, who take part in the Round the Island Race or other Island Sailing Club run events. We do not provide certificates. ISCRS is a relatively unsophisticated rule aimed at boats which do not race on a regular basis. It requires largely the same data as IRC and also, in common with IRC, provides rating allowances for cruising fitout.

How it works

Your finishing position will be achieved by multiplying your elapsed time (plus any time penalties) in the Race by your rating (TCF or time correction factor) which gives your corrected time. The boat with the lowest corrected time will be the winner.

Although ratings are based on owner supplied data, we keep a database of the details of as many different boat designs as possible and we try to check accuracy using all possible sources of data. This is particularly beneficial for production boats.

The formula for our rule (like almost all rating rules) is secret, however, your sail area and empty weight/displacement will play a big part. Subjective judgement where exercised is the sole responsibility of the Island Sailing Club's Rating Officers.

Your weight

If your boat is more than 8/10 years old it may well be heavier than when you purchased it. You will probably have added extra items, maybe changed engine/generators, or had repairs done. Many owners who take the trouble to have their boat load cell officially weighed find they will have a distinctly better rating as a result. Do note, however, that weights obtained from built in crane weighers or travel hoists are not accurate and should not be used.

A light boat will always go faster, whatever your rating, so in any event make sure you have taken off all unnecessary items (but NOT standard fixed fittings and furniture!) before the race.

Your sails

If you have a production boat with standard sails and you have not changed your sails since purchase, then we are very happy to accept the areas given in the brochure/specification that came with your boat. However, do be careful to check that you are giving the correct headsail dimensions and tell us if it is a furling or non furling one.

If your sails are non standard then we will need you to measure them. Once measured the details will stay on file and you will not be required to re-measure for a few years unless they change. See below for a guide to measuring your sails.

Please take special care in how you deal with giving us information on use of spinnakers. A few of you have a habit of ticking the wrong boxes when you fill in the online form. This has led to some boats receiving a lower rating for "no spinnaker" when they will, in fact, be using one. This can be seen by other competitors as cheating and you run the risk of being protested.

Measuring your boat and completing your entry form

As part of your online entry, you will be asked to provide the measurement data that will allow us to calculate an ISCRS rating for you. If you have non-standard sails and need to measure them, we suggest you download our ISCRS form below, which will help you measure and record the necessary details ready for your online entry.

Most owners who query their ratings find that it has usually been as a result of incorrect data being given when filling out the rating form, so please make sure that the data you give is as accurate as possible and if you are unhappy when the ratings go live on the website a few weeks before the Race then give us a ring and we will be happy to discuss the issue.

ISC Rating System Measurement Form View / Download