In thousands of successful nights spent on the hook, it is surprising how many times I have been caught in the middle of the night by a 60+
knot short thunderstorm, (or long duration 40
knot winter fronts). I anchor our 34' tri accordingly.
I always use my 30'
bridle, so the boat doesn't saw around, and always take the height from the water to the bow roller into the math when calculating the 7 to 1 scope. With my 1/4' HT chain acting more like
rope, and usually anchoring in shallow water, this 7 to 1 scope is very important! (It is the big heavy monohulls anchoring in DEEP water with 3/8" chain that get away with 4 to 1 scope.) Smaller, lighter boats can't get away with it!
If an anchorage is too crowded, I don't do the standard... "squeeze in there anyway, OR use TOO short a scope". I anchor somewhere else! All over the
Caribbean I was regularly anchored WAY away from the crowd, because other than true emergencies, the above
rule is etched in stone. Yes, I have a planing
dinghy...
I set my 35'
DELTA firmly at full reverse RPM! In firm sand or mud, I can do this right away, and I'm good to well over 60 knots of wind. In really soft Chesapeake jello mud, I can "usually" achieve this by starting S L O W. I reverse at 1,500
RPM for long enough to casually drink a
beer, then 2,500 for a few more minutes, very slowly working up to 3,400
RPM. I have a folding prop, so it has less reverse thrust than a fixed one, but anyone, over time, can figure out what amount of reverse RPM = what amount of wind... "more or less".
If I can't get proper holding like this and continue to drag, I try a couple of more spots.
If this doesn't
work, It is dark by now, so I put my huge
emergency Fortress on the forward wing, ready to deploy. (Since it got airborn once, I now lash it down!)
I never trust hard or broken up "gravelly" bottoms, or thick
grass, and if clear and < 30' deep, I freedive on the anchor. Several times my anchor looked great from the "viewing bucket", but I found it was hooked on a marl ledge with 6" of sand over it. This is when I poke around "down wind" and find a GOOD all sand spot or hole in the marl. I leave my lobster stick there as a marker. Then with a BIG breath, dive down, pick up the anchor, QUICKLY walk backwards across the bottom, and drop it in my marked spot. So far, this has been much quicker than the speed that the boat falls back, and my wife is at the
wheel... "in case".
Improper anchoring is the most likely way to loose ones boat! Getting it right is an acquired skill, but one well worth mastering, for your boat.
Hope this is of use... Mark