General News - Sprint 15 Minimum Weight
Date Posted: 16th July 2017 at 16:35 pm

There is a circular that has been sent to many of our members which is entitled “The Sprint 15 Weight Issue – an Alternative View”, which makes the case of not adopting the 110Kg minimum weight proposal. This circular which has been put together predominantly by owners of the new light weight boats and plays down the importance of weight and contains a number of inaccuracies and omissions. This note gives a better perspective.

The Sprint 15 is a production one design class similar to the Dart 18 and the  Laser. Unlike these classes, however, the Sprint 15 has had a policy of allowing small optional changes if approved at an AGM provided that:

  • The change makes no significant change to the boat speed.
  • The change is inexpensive.
  • The change can be easily retrofitted to all existing boats.

It is of paramount importance that we do not make the existing fleet obsolete. This policy has been successful and has maintained fair one design class racing.

In 2012 when Windsport were planning to move hull production back to the UK with new moulds they asked if they could save cost and  tooling by substitution of the (heavy) cocktail cabinet inner mouldings and replacing them with the bags that you will have seen in the new boats. We only agreed to this if the overall weight of the boat was not reduced as a consequence and rule 10y was passed to this effect. From the data we published in the Spring 2017 issue of the Newsprint magazine it is clear that this rule has not been observed.  It is also clear that reducing the weight by some 5Kg does not comply with any of the 3 criteria (above) for acceptable design changes (the boat is faster, the change is expensive and it is not possible to easily retrofit the change to the existing fleet). We had experience the same problem in 1988 when we found that Panthercraft had introduced a cheap Spark variant (the Spark Fun) which had no cocktail cabinets and was much lighter. We determined that the Spark Fun hulls were out of class unless they carried 2 x 3Kg corrector weights. This episode was reported* in the Class Struggle booklet by Nick Dewhirst which can be found on our website (*see  below)

Determining the speed advantage of the new light boats from race data needs a large amount of data as there are many factors which effect the result and also other factors (stiffness, new sails, etc) also make new boats faster.  The speed difference of weight alone can be calculated from the SCHRS formula and means that the new lighter boats are effectively 7 PY units faster than the lightest ‘old’ boat was when new and more like 14 PY units faster than the average old boat. This is nothing like the difference between an expert helm and an average helm but it is significant in that the light boat will generally win when 2 helms of equal ability take part – surely not the idea of one design class racing?

Like the Dart 18 and the Laser we have not had a minimum weight specification and did not need one up until 2013. Neither the Dart 18 nor the Laser have had their manufacturer take 2 heavy components weighing about 5Kg out of new boats causing a significant increase in boat speed. The intent of the 110Kg minimum weight specification is just to restore the position to the intent of the 2012 rules. No old boat with cocktail cabinets will need to be weighed as we are confident from the data we have collected that no boats with cocktail cabinets were ever lighter.

Comments on a number of the other issues that have been raised are as follows:

  • Our data shows a wide spread of weights of the existing boats.  Much of this is due to wear and tear (repairs) and owner neglect (boats not drained properly and left to absorb moisture). We are not trying to correct the old boat weight spread. We are just interested in restoring the situation to how it was before the removal of the cocktail cabinets.
  • Frequent scrutineering will not be required. Once post 2014 sail number boats have been weighed and weights have been provided just cursory checks that these weights are present will be all that is required.
  • The minimum weight proposal is kinder to new boats than the imposition of fixed corrector weights as was applied in 1988. This is because no new boat ever needs to be heavier than 110Kg even allowing for production variations, one or two piece mast, etc.
  • Many boat classes are required to carry weight correction. It is not clear that once the principal has been established that it will deter new boat buyers.
  • The new boats will remain faster than old boats due to being new and in better condition but we want to correct the unfair part of the speed advantage that is as a result of being lighter than any boats in our history have been.  We did not anticipate how vigorously some of the new boat owners would argue to maintain this unfair advantage.


We hope that you will support your committee by voting to approve proposal 1 to adopt a 110Kg minimum weight at the AGM on 22 July at Thorpe Bay.


* The following reference is taken from the booklet “Class Struggle” by Nick Dewhirst written about 1992.

“Thirdly we took a closer look at the boats and found out two interesting changes we had not noticed. At Seasalter the local Commodore, Fred William had come over to our fleet. He was pissed off too at being beaten by newcomers, but unlike some of us he knew a thing about weights and measures being a master builder. The boats were bisected. Each hull was balanced on a pair of bathroom scales brought down for the occasion. In proper scientific fashion a control group was set up - my hulls in fact. Well I never! Low and Behold! The demos were meaningfully lighter. Bob Hughes, the production manager, eventually confirmed that the difference was as much as 3 kilos. This was because they did not have our beloved drinks cabinets. However his solution was to phase out all the old Sparks. Make us obsolete, indeed! Kill the class, more likely! This looked like Panthercraft subversion again and stung me into my longest missive ever to the manufacturer. Fortunately they eventually saw sense. The cheaper, but faster all white hulls were discontinued. Adjustment weights were provided for old boats. So if you ever see one with all white hulls and colour sails and without grey blocks in the front beam, you know who is cheating.”