"Stephen Trapani" wrote in message
...
If the apparent wind, say, decreases *any* resistance by, say lifting
the boat a fraction, or changing the effective hull shape that is
hitting the water, then NORDHAVN's statement is technically correct.

Poppycock! NORDHAVN's statement is fiction. Pure fiction! Had they said
light air instead of dead air they would have been correct on any point
of sail other than with the wind dead ahead but they didn't say that.
They said dead air which means NO WIND. No wind will always cause the
apparent wind to be from dead ahead when motoring ahead and this dead
ahead wind can't impart any forward force to the boat because it can
only shake the sails around and cause drag on the sails and rigging
which slows the boat.

There are other ways hull design can return energy to the sytem. Look
at hydrofoils.

Sorry but the the 56MS has no hydrofoils.

NORDHAVN never claim that their design produces a net energy, just
that it returns some energy to the system, thus reducing the amount of
energy needed to propel the boat. This surely is physically possible.

It is only physically possible if there's a wind and provided the wind
is not from dead ahead. It is physically impossible in "dead air" as
claimed by NORDHAVN.

Wilbur Hubbard