Join Date: Mar 2006
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Actually, the Helix screw anchors are proven to be better than most mass-based anchors. By using anchor bends, instead of spliced thimbles and shackles, you're losing about 40% of the strength of the rope... They do make titanium or plastic thimbles, which are far less prone to rusting.
Depending on the size of the Helix Screw anchor, one should be sufficient to hold your boat...but YMMV. If you have to use two, it might be better to have the two chains joined to a three-way swivel, underwater, and have a single heavier chain coming up to the boat. Properly hot-galvanized chain should last a fairly long time.
However, catenary isn't as much of an issue when you're using properly sized helix anchors that are properly bedded, but having sufficient chain to allow for storm surge is a very good idea. The catenary curve can help absorb shock loading to a small degree, but the bulk of the shock loading absorption will have to be provided by the nylon pennants. BTW, oversizing the lines is probably a bad idea, as they will not stretch under the given load, and your boat will suffer from the shockloading.
Last question—what are you using for chafe protection? None of this matters if the rope chafes through. And you haven't mentioned any sort of chafe protection outside of using a bow roller. Also, is the bow roller large enough to handle two lines of the size you're describing?
Sailaway's points about the buoy are excellent...keeping the line away from the bottom is an excellent idea.
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You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.
—Cpt. Mal Reynolds, Serenity (edited)
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Last edited by sailingdog; 12-05-2006 at 06:44 AM.