T&T: Anchor rode snubber line size

[Albin43SDtr]

'Lo All,

My old sailboat, before I built the interior, which brought the bow 
way down (reducing bow windage), used to hunt like a cheetah on the 
savannah if anchored on a single line (two anchors spaced at about 
40-60 degrees stopped all hunting). Any boat that has the center of 
wind resistance forward of the center of lateral resistance will hunt 
to some extent. This is because the center of lateral resistance is 
the point where the boat moves sidewise without turning when that 
point is pushed. The center of wind resistance is the point where the 
wind force is centered. The greater the distance, the more violently 
it will hunt (all factors considered for that specific boat). The 
more windage relative to lateral resistance, the more violently it 
will hunt. This is why "riding sails" are put on sailboats. They are 
very effective, and were especially effective on our old sailboat.

I did find that if I rigged a bridle, setting a snatch block on the 
anchor rode and adjusting the bridle line with a main sheet winch, by 
shortening the bridle line, I could keep the bow from passing through 
what would be a straight line from the anchor, center of wind 
resistance, and the center of lateral resistance, thus stopping the 
incessant hunting. This essentially held the boat in a 
non-streamlined condition, laying on one tack. The greater the wind, 
the greater the angle of tackrequired to stop the hunting. Of course, 
it also significantly increased the load on the anchor. I did not 
like this arrangement and quickly adopted a two rode anchoring 
scheme, then ultimately made a riding sail.

The Celestial does not hunt, fortunately. That is one advantage to 
having the dinghy stored on top of the sundeck roof as well as the 
overall shape of this type vessel (full length keel, long aft cabin). 
When bringing her home after purchasing her, on our 2nd night aboard, 
as usual, I got up in the middle of the night to check the anchor and 
all and was astonished to find 2-3' waves running past us, but the 
Celestial was serenely sitting with no real discernable movement. It 
was quite noisy outside, but in the aft-cabin, all was quiet. :)

The advantage of a bridle, from my experiences, is to use it as an 
anchor rode snubber, and forget any real hope of it stopping the 
hunting tendency.

Just thinking out loud.... YMMVVG


Take care and be safe.

Wayne
M/V Celestial
Albin43 Sundeck
Panama City, FL area