The WSSR Council announces an addition to WSSR Rule 3 The Course
Insert new paragraph 3:
"Record claims will not be ratified when, in the opinion of the WSSR Commissioner, the minimum water depth over the whole course is below 50 cms"
This rule to take immediate effect.
John Reed
Secretary to the WSSR Council
Explanatory notes on the WSSR Newsletter No 155..
There has been much debate about the attempting of sailing records in very shallow water. The controversy has only recently come to light because up until now the need for skegs on windsurfers made water depth self-limiting. However the high speeds being claimed by kite surfers has circumvented this as although they need to "edge" their boards somewhat to generate lift, at 50 knots and at deep wind angles, the edge doesn't run very deep. There was a real concern that unless some sensible ruling was brought in, a world record claim using water only as a lubricant was a possibility. For example, creating a record course by covering a large car park with a plastic sheet and then wetting it to a few mm depth. There was a general feeling that this stretched the aim of breaking records on "water" too far.
There is much anecdotal evidence about the positive effects on speed by the shallow water effect and certain published study including the effect on fast ferries when entering shallow water and using the effect to "unstick" seaplanes. However in order to obtain some hard data, the Council commissioned the Wolfson Unit of Southampton to prepare a paper on the specific subject.
Their conclusion of this detailed study was that the drag of a planing board is reduced when the water depth is less than the beam of the board, with a possible reduction of 50% in very shallow water of less than half the beam of the board. A water depth of 50cm would be deep enough to avoid shallow water effects.
It was agreed by Council that to introduce a ruling which would require the width of a board to be measured in order to establish the water depth would be impracticable and thus an overall 50cms depth has been introduced, as follows:
"Record claims will not be ratified when, in the opinion of the WSSR Commissioner, the minimum water depth over the whole course is below 50 cms"
It is believed that this depth of water negates the "shallow water drag reducing effect" but does not disadvantage the usage of existing courses that are protected and relatively free from current and waves.
John Reed.
Secretary to the WSSR Council