Arild wrote:
"...The question is, are you going to set the alarm circle so tight that
normal
movement swinging at anchor is going to trip the GPS alarm?..."

....well, yes, that's actually not a bad idea!!  (But not necessary.)(I'm not
debating here that either WAAS or DGPS is more accurate, simply discussing
how either can be used to great advantage for anchor alarms.)

There are some variations on this theme.

With an all  chain rode and a tight  alarm range on a quiet night, if  the
anchor alarm sounds I've been alerted to a change in weather conditions which
warrants a visual check.

Setting a tight alarm range on a windy night  informs me of a change in wind
direction with any type rode...or dragging.  I still remember  '01  just
outside Cuttyhunk (Mass)  anchored overnight near the entrance bell buoy in
rain,f og, gale force winds, in a grassy bottom, alone (with dog). It  was
howling!!  I could not see the bell buoy about 200 feet away..or anything
else...but could hear it intermittently. It was the first time I felt the
anchor alarm really earned it's keep...I knew if I dragged or my chain parted
I'd be alerted before I got to rocks on Penikenese Island astern. It was a
great comfort and turned what could have been a near sleepless night in one
of rest and comfort..

Arild also posted"...In fact if this is the only thing you rely on when
anchoring out, please
don't invite me to stay onboard ovenight..."  Well, I'm not sure exactly what
he had in mind here, but if one sets their anchor correctly, uses proper
tackle for the job, then the key third step is having an alarm in use to
cover unpleasant surprises.

regards,
Rob Brueckner
Hatteras Yachtfish

Arild wrote: "...In fact if this is the only thing you rely on when
anchoring out, please don't invite me to stay onboard ovenight..."

Actually I have one other early warning system that I use. At my age I need
to pee about three times a night. This gives me a chance to go out on the
deck and walk around.

This system actually saved us and a sailboat a lot of trouble last October
in Dividing Creek of Wye River, Chesapeake Bay. On one of my nightly rounds
on deck, I saw that the sailboat, which originally had anchored 100 yards
away, was now 20 yards away and its dinghy and stern would soon swing back
and forth across the point where my rode disappeared into the water. They
had drug down on us and probably were going to continue dragging.

Fortunately a spotlight through their cockpit and into their cabin got their
attention. I did have to let them know when it was safe to put their engine
in gear when their sailboat had safely swung away from my rode.

So my advice is, drink plenty of liquids before retiring and do whatever you
can to enlarge your prostrate. %^)

-- Jim

Jim & Rita Ague
M/V Derreen, Monk 36
ague@usa.net