Thanks guys - I understand why these threads get so heated now that I've worked up to overnight anchoring.
I'm currently in Marina Del Rey, Los Angeles, and the waters of Santa Monica Bay are where I cut my anchoring and keel boat
There are no protected anchorages
here, with the exception of lovely King Harbor, which I only recently figured out was permissible to anchor inside the breakwater for 3 nights, free.
Every other "anchorage" in the bay cannot even be described as "marginal" - they are "Horrible" always in at least 30 feet of water
you must anchor this deep to avoid the open ocean swells and breakers, and they are ALL against a lee shore, where every summer afternoon the wind
blows 15 to 20 knots (or more) against it.
Until recently, I used a 14lb delta
30 or feet of chain, and 400 feet of 1/2" nylon in these "anchorages"
(I'm preparing to cruise
, and figured if I can sleep in these conditions....)
Naturally, the few times I anchored overnight in these horrible places, the wind
kicked up in pitch
black darkness and started howling in the rigging
, forcing me a couple of times to scramble on deck
in the middle of the night, start the engine
, and stub my toes, chaffe my hands and break my back hauling that gear
back aboard while not ending up in the breakers.
experience that convinced me to find the best anchor possible, double it's size, put it on all chain (with a snubbed rigged to BASE of my bobstay) and install a windlass.
Oh, and set a couple of anchor alarms on various GPS
devices (I-Pads "anchor alert" is my fav.
And I was able to sleep like a baby believe it or not even before the hurricane
strength portable mooring
system now decorating my bowsprit
- yea, it looks silly up there on such a small boat
, but I don't drag....
My buddy (the one who dragged all over Emerald bay) is always arguing with me about the merits of his CQR
"I DIDN'T DRAG, MY ANCHOR TRIPPED WHEN THE WIND AND SWELL SHIFTED!!!"
Yes - and it didn't reset did it?
(Yup, he's a sailor)
Anyway, no one wants to have even a shred of doubt about thier ground tackle - too much is at stake, so once you invest in it....you will defend whatever you have as "The Best" just to convince yourself.
That's why I upsized and overkilled everything. Even though a 13lb Rockna on nylon is overkill for a 6,000 lb 20 foot pocket cruiser
99.9999% of the time - that extra 10lbs on the bow nearly doubles the weight for penetrating hard Seabeds.
225 feet of chain means shorter scope
(no matter what the eggheads say, even in storm conditions you will have a cantenary curve to it, and as it surges, the curve will increase right at the bottom (and top) pulling the anchor horizontal, and digging it in deeper and deeper with each cycle until either equilibrium is reached and the anchor stalls, or the bearing value of the seabed is exceeded and you drag - to a point more scope will prevent breakout, but not necessarily dragging - that will be a function of the afore mentioned soils variables, anchor surface area, geometry, and embedment - assuming there is no structural failure of anchor or deck hardware
(I'm currently experimenting with progressive snubbers by rigging
one or more softer elastic sections to a stiffer overall snubber, you should be able to dampen the loading (spread out the force over time F=MA, less acceleration (velocity increasing or decreasing with time) means less force.)
This is a principal we use in seismic design - where you have two basic options: make the structure stiff (and usually brittle as a result - see reinforced concrete) or flexible, then carefully tune it's period of resonance to avoid harmonizing with the expected forces (constructive interference).
I don't like stiff systems subjected to dynamic loading - after the next big quake hits the papers, look at the majority of buildings that collapse and trap or kill folks.
Yup - they are usually concrete or brick, and often unreinforeced with (relatively ductile) steel
The cool thing about Newtonian physics is that they are based on universal laws that apply to everything, at least at the scale we inhabit...