Hi Arto,
These armchairs go well to weather in all conditions and never have to compromise.
I must be getting set in my ways as I get older as I haven't modified what I want in a bow for a few months now and have been rabbiting on about the importance of low down bouyancy in bows for over 30 years.
What convinces me is looking at vessels and creatures that are designed to work underwater. They tend to go quite fast and are not particularly sharp in their noses. If you put your hand in the water playing with shapes while sailing along there is quite a difference in force against your hand when having the hand just under in a mouse shape pealing the surface off rather than sitting on the surface pushing the water down and sideways.
Latest thoughts are reverse bow of Alinghi angles with v bottom of about 75 degrees to cut down on slapping when coming off the back of the wave and also allowing a cleaner exit when it becomes a stern. I am considering possibly up to 90% prismatic coefficient on a 19:1 length to breadth ratio for a 15m/10m Harry. Spray rails on the windward side leading to a flare under the crossbeam would increase bury of the crossbeams and provide lift without leading to hobbyhorsing.
The windward hull has very different forces acting on it, as the harder the boat goes, the higher it sits and it is more affected by surface waves so I get drawn to bows and hulls of power cats with wave piercers but also with spray rails on the ww side to keep the boat drier flaring out to a 200mm flare in the centre. With just the right angle of rise I have an image of the hull skipping along the surface chop on the front half of the boat. This is similar to a small tri I built almost 30 years ago that seemed to work this way. At lower speeds, it behaved itself as a displacement hull. I think the is bow as a stern would be reasonably efficient as it is not that much different from the stern of a moth foiler
Time to leave the armchair and do a bit
regards,
Robert
--- In harryproa@yahoogrou
>
> There is currently interesting discussion going on at multihulls list on bow shapes of new Oracle BMW and Alinghi. This brings to mind the discussion on this list some time ago on bow shapes where Robert advocated similar aft raked bows that are now very hot in racing circuit. The more I follow the discussion the more it would make sense to have such bows on harryproa, at least on lee hull.
>
> Arto
> still arm chair boat builder... :)
>
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