NielsNL
04-24-2006, 07:19 PM
I am trying to optimize the hull shape of a 10m 'Zeeschouw', a hard chined traditional Dutch fishing ship: flat bottom & leeboards and very suitable for shallow water.
Class regulations demand the location of the largest station is > 10% of LWL fore the center of LWL. However, several items on this forum indicate that a slightly aft location is preferable. For this reason Gerritsma once said that these ships would be probably faster when sailing backwards...
I've made several hull shape studies, using a standard Zeeschouw as a starting point. It seems to be possible to move the top of the COA about 200mm aft when I create a relatively full aft section. However, this also leads to a higher prismatic coefficient, which easily shifts from 0.57 to 0.60.
Should I prefer the more aft COA top or the lower prismatic ? I am afraid the parameters of this model are not in range of the Delft series, so I can't use the resistance module of FreeShip.
Class regulations demand the location of the largest station is > 10% of LWL fore the center of LWL. However, several items on this forum indicate that a slightly aft location is preferable. For this reason Gerritsma once said that these ships would be probably faster when sailing backwards...
I've made several hull shape studies, using a standard Zeeschouw as a starting point. It seems to be possible to move the top of the COA about 200mm aft when I create a relatively full aft section. However, this also leads to a higher prismatic coefficient, which easily shifts from 0.57 to 0.60.
Should I prefer the more aft COA top or the lower prismatic ? I am afraid the parameters of this model are not in range of the Delft series, so I can't use the resistance module of FreeShip.