The limitations of the present forms of wind assistance for ships
and how a vast improvement could be made using "headwind" power.
The methods used up to this time to assist the progress of ships and boats
have severe limitations in that the thrust applied to the craft is only
optimal for 2 wind directions, one on either tack.
A glance at this graphic below of the polar of a sailing boat shows that there are only 2 places in the entire 360 degrees where the thrust is at maximum - all other headings of the boat relative to the wind reveal a falling off of thrust until if the wind comes ahead or nearly ahead there is no thrust available.
The systems starting to be fitted for wind assistance are
Turbosail based systems, wingsails,and kites. All of these systems use
the wind coming from the side (90 degrees) to the heading of the ship.
There are only the 2 spots within the full 360 degrees where the thrust is
at maximum, and on all other
headings there is a diminishing of the thrust and complete lack of drive
when the wind is directly ahead of the boat. Flettner rotors and
Turbosails have the added disadvantage in that the windage (drag) of their
vertical towers hinders the ship's progress when the wind starts to come
ahead of the craft. Wingsails do not suffer so much from this drag penalty
because they can be aligned accurately with the wind or folded down to produce minimum
Introducing Headwind power
So what is "Headwind power"? Sailors have learned for many centuries that
a headwind will push their craft back and prevent progress towards where
they want to go - it seems natural and easily understood. "Sailing against a
headwind" is a term used even outside sailing to suggest a resistance to
Further tests need to be made such
Example of a layout of a ship incorporating both headwind power and sidewind power. Thus eliminating any directions where the wind is not favourable.
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