Hi all,
To Bill and all the other posters, I would just like to say Thanks for posing and answering such stimulating questions.
I have one of my own. We have pretty much established the relationship between centres of effort, buoyancy, hull and deck forms etc in their effect on PP resistance, but I was wondering about one aspect of dynamic lift. O.K I have seen threads on foil assistance either in the form of T foils (as seen on the Australian moths, the Stealth F18HT and F16 and on many I14 skiffs) and inclined foils as used on the ORMA 60 tris. There is no doubt both these devices will allow the boats to be pushed harder downwind although in extreme conditions the foils may work against you. But what about concavities in the hull under the waterline forward of the main beam. Sailbooards have being using subtle concavities for some time to promote early planing and recently I tested a seakayak with slightly concave rear sections to help lift the stern when paddled hard. This very fast kayak the result of computer modelling and tank testing. Could the acceleration of water under the hull on a beach cat provide enough useful lift at speed to hold the bows higher and so allow the boat to be driven harder? Bill have you done any work on this?

Cheers

Simon Fisher