Oh goodie, another anchor thread.... But I haven't been in one yet on cruiserforum.net so here goes.
idea, and the one I happen to accept is that you will get the most ultimate holding power by going to the largest anchor you can figure out how to get back in the ow roller. There is no such thing as an anchor that is too big.
The reality is that traditionall boats use anchors that are really too small, but they are the largest that can be hoisted onto the deck
. This goes back as far as the british navy
, using twenty man capstans. But since they recognized that the anchors still weren't big enough they added large chain to get more weight on the bottom. This is only starting to change with the advent of electric
and hydrolic wind
lasses, but sailors being a conservative lot tend to stick with what worked in the past regardless of why.
Now let's take a boat with an anchoring
of say 300lbs. Typically you would expect to see a 60lbs something, combined with 240lbs of chain and line. However the holding power of a 150lbs anchor with 150lbs of chain/line will be orders of magnitude larger, though it does make it problematic to get the anchor up.
As for the amount of ride to put out...
is defined as the relation between the height of the bow roller to the bottom, and the amount of line let out. The leingth of the boat is simply not a factor.
Second, The numbers say that up to 10:1 scope
significantly decreases the angle of the anchor to the sea bed
. Beyond this while it does help, it changes the angle so slowly that it is rarely worth giving up the swinging room. Though if you had an anchorage to yourself go for it, it won't hurt anything.
The recomendation for a minimum scope is generally going to be 5:1, however this is based upon a traditional sized anchor for the boat. By going to a massively oversized anchor you can get away with less, but again the gains up to 5:1 or so are very significant, very fast, so worth it in most conditions.
A good example of this is the Dashew's Windhorse that sat at anchor in a 60kn blow with 2:1 scope out and never budged. But they also carry an anchor that would normally be sized for a boat 3-4 times their size.
Third. The cantenary effect of chain is massively overblown. For most boats, it will take between 30 and 35kn of breeze to load up a chain rhode to bar tight. Beyond this there is no cantenary advantage. This is leading some people to consider switching to spectra anchor lines, to move even more weight into the anchor (or reduce anchor system weight). I am it willing to recommend this until i see some more testing, but then I'm a sailor, and tend to be conservative.
Finally. Shock absorbers are a great idea in most conditions, but I wouldn't worry about it too much in storm conditions. The shock loads I have experienced in strong blows are actually pretty light. Much more important in my eyes is to massively reinforce the backing plates
, and cleats
used to attach anchor lines to the boat in the first place.
are more than strong enough, and so long as the fasteners aren't rotted they are likely to be more than strong enough to handle the loads. It the fiberglass
they are bolted to, particularly if all you have is fender
washers will rip out in a hurry.