You say that “ at these low speeds the drag from the hulls is almost entirely created by wetted surface drag” wheras the Miss Nylex data you present shows that there is a 60/40 split. I don’t know off the top of my head at what speed or Froude number this data is taken but I bet a cold beer its higher than 6knots. At 6 knots the split would be the other way around 40/60 with wave drag taking the higher percentage of drag. Surely the Miss Nylex numbers back up what I am saying.

That is why I say that wave drag isn’t negligible. When I say there is bugger all in it between a 5.5m and a 5m hull. I am saying that the wave drag has a big influence on total hull drag but changing from 5m to 5.5m length only is not enough of a change to affect the wave drag by much. A thinner longer hull is always better but reducing displacement is the real key.

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