4. CONCLUSION

We have found optimum dimensions for K1, K2 and K4 class kayaks for a range of displacements and design speeds. For the K1 and K2 classes, it seems that hulls with parabolic waterlines, elliptical cross-sections, and rectangular keel-lines are near optimal. Shape effects are more important for the K4 class kayaks. We have remained silent as to the stability of the kayaks and how this would affect overall performance.

The "optimal" hullforms we have found have features that are well known to reduce some component or other of the total resistance, but the optimal hulls are not very much better than one might design on a naive basis. There is little room within ICF rules for radical hullforms, and consequently we did not expect radical improvements. At this early stage we are quite content to have put some ideas on a firmer footing, and to have established a set of hullforms that can be used as benchmarks, and from which extended studies can follow.

5. FURTHER INVESTIGATIONS

• The paucity of published results of experiments on existing hulls makes validation of mathematical models very difficult.

• Sinkage, trim, planing and semi-planing effects should be assessed.

• Unsteady effects might be important if the boatspeed varies dramatically during the paddling stroke cycle.

• At some speeds the "best" and "second-best" hullforms have almost identical total resistances, but their dimensions and shapes are different. These hulls should be compared on some basis apart from total resistance: stability considerations seem to be the obvious first choice.