One of comments on the storm anchors thread was:
" It will be much easier on the boat to keep the pointy end into the
wind."
I disagree. I would use of stern (the blunt end) in a survival storm.
The work of Don Jordan (an aeronautical engineer now in his 90s)
found more boats lost in hurricane anchorages would be saved if
they had been anchored from the stern of the vessel.
According to his research most sail boats will 'sail at anchor' far less
if the wind strikes them from the stern than the bow. Due to design
requirements, if a boat's mast is not providing the center of
movement forward of the the midpoint, the boat will not steer
well. But when at anchor in a strong enough wind, the same mast,
contributes to the boats instability. It may not be as evident at
small velocity winds, but at hurricane force, it will whip one way
then the other. Its why some boats put up 'riding sails' at the stern.
The stronger the wind the more lift it produces to induce more sailing
when anchored from the bow. The more lift, the more chafe.
However anchoring from the stern in hurricane winds
introduces a straight line drag, from the mast being
downwind, and the boat laying straight eliminates many
chafe issues that cause boats to be lost when lines part.
There are those who worry about the boat being pooped during
a 'rear anchoring' but research shows there is more lift at the
stern than at the bow of boats, and where you see a bow dipping
low into the water and then pitching high, the stern will float
with less movement and pitching due to its greater lift.
I have put in steel plates at the stern corners of our catamaran
that will take any strain and support a yoke. If I still sailed my
35 foot monohull I think the corner cleats would be sufficient
to make a yoke (twice the beam of the boat) from which to
use a stern anchor.
I will also use a heavy kellet on the rode for the anchor (in our
case we use the heaviest mushroom anchor we could find).
also.....
An insurance surveyor investigator years ago told me he had
observed that bow eye anchored boats with 'bow eyes' tended to
be less frequently lost in severe storms than boats with lines
led from the deck -- which I believe is attributable to less chafe
and a lower target for wind when it swings at anchor. (it also
obviously has a higher scope this way).
Ed
Ed Kelly (& Sue Kelly)
USSV Angel Louise - a Catalac catamaran now lying Kittery, Maine
shortly to go South when the hurricane season is over.
Our Skype Phone (202) 657-6357
Email: EdKelly ("at" symbol) netins.net
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