Sep 1, 2014

18' Outwards Foiler?


Render sent by Carl-Johan Söder - There is nothing wrong with this render according to Carl.
He designed a foil solution as the one used by Artemis on their flying AC45 and straight dagger case and stepped foil design, to be used on an F18 platform.
I commented on this project that F18s are not prepared to handle the loads of a foiling setup, and that the FP and Nacras have suffered breakages while testing foiling solutions. I Have reports from Alex and the custom F20 on transom, and structural failures on the long & tough process of making these 18-20' beachcats to get airborne time while staying ready for the next ride.


Beyond that, his outward configuration implies some degree of risk while sailing with other boats, not even to start speaking of racing.
But Carl is targeting mainly on free rides,  and literally thinking out of the Box to provide a more stable ride, although current TNZ foils used in the FP and F20 are already pretty stable solutions. --
Check his comments on this outward setup:
"I have developed a conceptual F18 ”hybrid” that would be great if you would like to post - perhaps someone may get interested in building it..

Main feature is the self stabilizing foil configuration that fit into straight cases. In contradiction to e.g. the A.C. configuration these foils moves the centre of lift outwards which increases the righting lever and thus the power. In addition, the efficiency of producing vertical lift with this configuration is higher.

In fact, VPP estimates suggest clearly superior performance upwind compared to customized foilers (such as FP) in +9-10kn due to more power, even though the platform would be some 15% heavier. Downwind however, she will suffer from the weight and smaller sail area but will still easily leave non foiling F18’s.

The idea with the concept is to provide a design that both can be used for competing in F18 events (while fitted with conventional boards) and for freeriding as well as long distance races in foiling mode."

Carl-Johan Söder
CJ (Naval Architect and Ph.D student within the field of ship dynamic stability) 

cjsoder (at) kth.se

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