The vessel type: monohull, catamaran or trimaran, is defined in the Vessel Type dialog. This additional model information is used in other programs in the Maxsurf suite. Currently Hullspeed uses this information to define the panel arrangement for the slender body analysis. The other programs in the Maxsurf suite do not use the vessel type information yet.

You should set up the Frame of Reference and Zero Point first. Then, when the design is finished, the Vessel Type can be setup. None of this data is changed automatically, so if you were to increase the demihull separation of a catamaran, it would be necessary to return to this dialog to update the data manually.

For the monohull vessel type there is nothing more to specify other than that the vessel is a monohull from the ‘Number of hulls’ radio items.

In the case of a catamaran, you should select the appropriate radio button and specify the offset of the local demihull centreline. Analysis programs, such as Hullspeed, will use the local demihull centreline when computing the analysis mesh for the model.

For trimarans, you must specify the centreline offset location of the outer hull and also the transverse extents of the main hull. Again these data are used in analysis programs such as Hullspeed. The transverse extents of the main hulls are used to clip the sections used in the analysis programs so it is generally sufficient to only include the underwater part of the main hull.