Larger LB indicates a slimmer hull.

Catamaran hull length to beam ratio. Weight and length can be combined into the Slenderness Ratio SLR. Thats acceptable as for a given cross-section shape the SLR is directly related to LWLBWL. A twin-hull is exactly what it sounds like- it means that the boat has more than one hull.

Lengthbeam ratio of the catamaran L BRC L BRC L H B CB If we set L BRC 22 the longitudinal and transversal stability will come very near to the same value. 5 are consistent and reasonably close. Most modern trimarans are a bit higher than that.

Typically this will be 8-101 for a slow cruising catamaran or the main hull of most trimarans 12-141 for a performance cruiser and 201 for an extreme racer. Hughes designs seem to have the least scatter for the catamarans with length to hull beam ratios generally in the range of 10 to 12. The calculations for a catamaran are more complicated.

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. The trends between numerical and experimental results in Fig. Its generally accepted that for a planing hull for normal service one shouldnt employ a length.

Typically the LWLBWL ratio will vary from 101 for a good cruising. A catamaran was created with a twin-hull trusted buoyancy and an innovative beam to length ratio designed to provide stability and a smooth ride when navigated by the average sailor. For a displacement catamaran to be effective hull length to beam ratios of at least 101 should be aimed for and if possible even higher.

The wetted lengths at keel LK for test data are calculated from the reported mean wetted length-to-beam ratio λ using the equation L K λ b b π tan β tan τ given by Morabito 2011. Hull Fineness Ratio HFR The Hull Fineness Ratio known as the hulls beam-to-length ratio is an interesting number. In the case of a catamaran which has no keel to weigh the boat down slimmer and more hydro dynamically optimized hulls this theoretical hull speed rarely applies.