SPEAR - royalty fee
Details
SPEAR - A Class design - royalty fee.
A modable design that can be rated in the range 14.5 kg/1 m2 to 16.5 kg/0.9 m2 to suit local conditions. VPP.
The prototype SPEAR was created by Selwyn Holland by3D printing. The files for printing can be obtained from Selwyn (please ask Selwyn about fees for accessing his files). A royalty fee per boat built from those files is due to SAILSetc and can be purchased here.
A traditionally built SPEAR by Martin Dovey (see Licensed Builders) won the 2023 GBR A Class Nationals in the hands of Centenary Free Sailing A Class Champion Chris Harris.
The A Class class rules impose no restrictions on the materials used for hull construction. Hence the best quality thermoplastic can be used to construct hulls and other component parts for an A Class. Due to the relative insensitivity of boat performance to ballast weight (hence construction weight) the performance of a fully printed boat is relatively unaffected by any increase in construction weight.
The hull form of SPEAR is closely related to the successful SWORD design but has been adjusted to allow the waterline length, displacement and sail area to be varied over a range that allows the boat to be tuned to suit local conditions. At winds under 7 knots the lighter configurations will give better results. Above that wind speed the heavier configurations will have a distinct edge to windward and superiority in gusts. If handled well enough to avoid control problems the performance of all configurations around a traditional course is almost identical for winds over 7 knots due to the better downwind performance offsetting the poorer windward ability of the lighter configurations.
The rig of SPEAR has been designed to permit the same headsails to be used for all configurations with different mainsails. If the lower mainsails are sized for the heavier modes then only the largest mainsail needs to be replaced when using the boat in a lighter mode.
Contact Martin Dovey (see Licensed Builders) for traditionally moulded hulls and completed boats to the SPEAR design. Printing hulls offer the possibility of hulls to this design without the investment necessary for traditionally built hulls.
Yacht Design Notes - log of SAILSetc designs over the years and a brief description of each.