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Mooring line size?

Discussion in 'General Yachting Discussion' started by Danvilletim, Mar 7, 2015.

  1. Danvilletim

    Danvilletim Senior Member

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    isleton, ca
    We want to double moor at angel island is San Francisco Bay. We are told we need a 100' and 200' lines. Were likely to not do this much but want to be safe.

    What size line? Boat is a 62 striker. A big 62 w 21 beam. 78,000 I think.

    3 strand nylon seems to be the best bang for the buck?
  2. NYCAP123

    NYCAP123 Senior Member

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    Mooring or anchoring? For anchoring that boat I'd be using all chain. When I ran 65' crew boats with no anchor windless or chain I believe we used 1 1/2 or 2" line, about 250' the few times we anchored (in the ocean). From the little I know about the currents and wind in SF Bay I wouldn't want to leave the boat with less than a 10 / 1 scope of line, and better a 20 / 1 if not using much or any chain. If you're mooring to a ball that length shouldn't be needed, and you can double up whatever you have for strength.

    Keep in mind that line will stretch up to 1/3 its length.
  3. Danvilletim

    Danvilletim Senior Member

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    This is mooring. There is a bow and stern mooring ball. The extra length on one is to allow room to navigate to second. The currents and wind still do rip pretty strong in this cove.
  4. NYCAP123

    NYCAP123 Senior Member

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    That's odd. I've never seen that setup although in the Bahamas they often anchor that way. But that still means that your friends are saying it's over 300' between the balls. That's really odd. In most mooring fields you simply grab one ball and swing on the tide a few feet from the ball.
  5. AlfredZ

    AlfredZ Senior Member

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    Hi,

    Measuring 1/8" of diameter per 9' of boat length will put you in the 1"-1 1/8" diameter region. Mooring in the Ayala cove, some people like to double the line on one or both tie points fore and aft, tried it once and had less motion astern. As you know not all balls are spaced the same, so the length suggested is safe. I add that the cove is a very busy location and the current are not forgiving, so, if you can manage practicing your technique with your crew in a approach and and ball pick up and picking a place where you don't make it harder for others to reach moorings that are closer to shore. If you can do that during week days if you are close by.

    Three strand as you said, will be the least costly than a plait of a braid. If you will double the line, you might want to consider a mooring hook, if I remember it was about $30 maybe, no laying down on deck and fussing with ball and line, the only thing is, you will need a short leader line cause the eye on it is short of your target diameter.

    Hope this helps.

    Cheers.
  6. DOCKMASTER

    DOCKMASTER Senior Member

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    If it were me I would not use 3 strand nylon, I would use a double braid. When tying to a mooring you want lots of elacticity. If the double braid is too expensive I would make sure to get a good long snubber to tie between the 3 strand and the can. I tie to moorings all the time up here in Alaska and always use double braid. I simply tie one end to the boat, run the line through the eye on the mooring with a boat hook and then back to the boat. This makes it simple to disconnect when it is time to leave or if you have an emergency. It's also a lot easier than trying to tie to the can. I come stern to to get the line thru the eye since it is a lot easier to do from the cockpit then have my deckhand simply walk the line to the bow as I come past the mooring. Works well for me.
  7. Caltexflanc

    Caltexflanc Senior Member

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    The set up at Ayala Cove is unique. Bow and stern tie up is mandatory. The reason for the lengths is that the common practice is to loop the line through the ball eye and double back, which makes retrieval simple and allows adjustments on the fly. If roughness has taken place or staying multiple nights, adjust slightly on a regular basis to cut down on chafe. Because of that, 3/4" typically works fine for larger boats. 3 strand has more elasticity than double braid and it will be rare you see double braid used there, when you do, it's typically because all they had was some dock lines.
  8. DOCKMASTER

    DOCKMASTER Senior Member

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    Sounds like a good set-up. I'm not sure what tye of 3 strand you use, but from what I've always seen, a double braid has more elongation than 3 strand. Most double braids are in the 35% - 40% range. 3 strands can be as high as 40% or as low as 10%. As with any line or set-up, you really need to verify the specs of the specific line you are using.
  9. dsharp

    dsharp Senior Member

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    3/4" 3-strand nylon will have plenty of strength. Any larger and it gets heavy and difficult to handle. How much line stays in the water? Poly line will float but, it's terrible line to work with after it starts to break down.