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Anchoring: scope, bottom and checks
An anchor does not hold through its weight but through the direction it is pulled in. Everything about anchoring comes down to keeping that pull flat, and keeping it flat all night.
Scope
As a rule of thumb four to seven times the depth, measured from the bow roller, not the waterline. In tidal water work with the highest level of the night, otherwise the chain stands up steeply at three in the morning.
The bottom
Sand and firm mud hold well, weed and rock hold badly or not at all. The chart says so and the water shows it: over weed the anchor sits on top instead of digging in.
Setting it
Lay out the chain, then build load astern with steady power and put a hand on the chain. If it snatches and grinds, the anchor is still moving. When it goes quiet and the chain comes taut, it is in.
Checking
Take bearings on two fixed marks ashore and write the values down. Check them every half hour at night. The anchor does not announce that it is dragging, but the bearing does, long before you feel it.
What this has to do with insurance
Providers differ sharply on anchoring with nobody aboard: some require the yacht to be permanently crewed, others include it. If you lie at anchor overnight or for days, read that line in your own policy wording before you need it.
