Leigh Sutherland

Windsurf Fins & HydroFoils

Over the years I have worked with Steve Cook at ‘F-Hot fins’ who make windsurfing fins for top professional sailors. Although the fin is physically small, it is an extremely important component which we have found to be at least as critical as the sail or the board.

My MSc. Research Project in 1993 on the ‘Hydrodynamics of Windsurfer Fins’ included a global force model and Velocity Prediction Programme (VPP), classical aerofoil theory, Computational Fluid Dynamics (CFD) analyses and tests in the Southampton Solent University towing tank.

This work has now been developed and expanded, in seven main areas:

  1. Computer Finite Element Analyses (FEA) structural analysis,
  2. Mechanical strength and stiffness tests,
  3. Computational Fluid Dynamics (CFD) modelling of the water flow,
  4. Water tunnel testing in Newcastle University’s Emerson Cavitation Tunnel,
  5. Fluid-Structure Interaction (FSI) modelling combing 1 & 3 above,
  6. On-the-water testing by professional windsurfers, 
  7. Fin optimisation using the previously developed design tool.

Published results can be found here, and results from initial on-the-water tests appear to confirm the predictions of the FSI model (over those of simple CFD) in terms of performance and handling.

Further work is now underway to optimised the internal ply layup and to test candidate fins in the Bolderwood Towing Tank at Southampton University

Similar approaches are now also underway to model the foils of the International Moth dinghy (in collaboration with Trimarine Compósitos LDA), the Técnico Solar Boat, and the MobyFly zero-emission hydrofoil boats.