"cvj" wrote in message
. ..

38 foot sailboat
35 lbs anchor (Plow type)
all-chain galvanized steel rode (300')
mud bottom
sheltered anchorage - calm day - lots of other boats at anchor
High tide mark at 20 feet above bottom.

Whatever the boat, whatever the rode, the angle of pull at the
anchor should always be as horizontal as possible. If the angle
is greater than 10 degrees, you're increasing the risk of the
anchor pulling out. Whatever the rode, in windy conditions the
boat will ride from side to side, jerking that rode, lifting the
chain to almost straight from time to time. If you want a secure
dig, that lift must not go above 10 degrees. That implies six
times rode of your depth at waterline. At high water.

And if you're going to leave the boat, check the risk of the
wind/tide reversing. That may trip the anchor. In which case you
need to moor. Lay a second anchor and dig it to hold in the
opposite direction.

For a lunch stop in a calm, by all means drop twice or three times
your depth. That's not really anchoring - that's putting a weight
on the bottom. But it's easy, it's fun, and it's safe for a quick
stop when nothing's going to change.

Ignore people who talk catenaries, or who quote lesser amounts.
They're not talking dynamic conditions, which is what matters. Add
a nylon snubber to soften stress loads in waves - 10m metres
worth at least.

Some will differ from my views . . . some of those older books
also were written in the dark ages, when the science of anchoring
was passed on from generation to generation . . . and only applied
to their local waters.
--
JimB
http://www.jimbaerselman.f2s.com/
Describing some Greek and Spanish cruising areas