Both the ESS hull and UK hull line
are derived from
offsets at the frame sections, the 1920 hull plot, from the
Amsterdam Maritime Museum, have been derived from the vessel's
offsets on the waterlines, and only up to the deck level. Frame
spacing for the ESS and 1920 hull is at 500mm, UK replica frames are
typically spaced at 610mm at best and some may
have some hull side frames spaced at up to 2m.
shorter, beamier ESS hull would be expected to show a higher drag than the
longer hulls. However, at 10 knots it is not significantly more
than the slimmer 1920s hull. The 1920 hull would have been
driven typically by a
50Hp single cylinder Bolinder type diesel. There are a number
of hull drag formulae depending on the type of hull, but the two shown
are typically used for small displacement hull calculations.
Drag curves do not show significant change with different