P m 4 x m LDC 1025P m 28.

Catamaran hull cross section. Zone of smooth transition of their configurations is located between fore and aft said transition including section of smooth elevation of vessel bottom mid part from single-hull fore to actual waterline in tunnel area between aft catamaran floats. So fine hulls are only an advantage if your boat is light and has enough sail area to ensure youre travelling at speeds where form resistance is greater than skin resistance. For stability and speed prediction see diagrams.

The more you make the section shape into a deep V or a broad U with tight corners as opposed to a semicircle the more wetted area you have. 1c it will be called a normal setup for the rest of the paper. Cross-section of single-hull fore and catamaran aft feature smooth curvilinear configuration corresponding to hull-borne mode.

However as the boat speed increases the hull begins to cause a wave to form at the bow that propagates away from the boat but also forms a hump toward the front and a dip towards the rear of the boat hull itself. The desirable height is proportional to the catamarans beam as measured from hull center lines. A fat hull will have high form drag.

A flat run aft in cross section will promote planing or semi planing at speed. Technically the cross section curve that best satisfies this requirement is a semi-circle however opinion appears to be divided as to whether a semi-circular cross section has any form stability at all. Canoes usually feature one of three hull cross sections.

Please note these are not to scale and are not real boats instead they are just examples of the different hullshapes we use in our designs. The following sketches are typical hull cross sections. Catamaran Sailboat Wide Bodied Hulls.

For wind ward performance the boat has depending on your choice anti-vortex panels a single dagger board in the port hull and my favored solution a a center dagger board under the bridge deck. From this it can be seen that it is not really practical to build displacement catamarans at less than 8m in length as this will translate to an 800mm beam for each hull at the waterline. Rounded hull cross sections are often the choice way to do this.