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Quick Question About Anchoring

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    Quick Question About Anchoring

    Tomorrow we'll be anchoring overnight in a cove for the first time. I've been reading up on the process and I get the idea, but there's one detail I'm not clear on: If i'm letting out enough anchor line to be 7 times the depth of the water, is that going to be the current depth or the expected depth at high tide?

    Thanks.
    "Binti B"
    1996 2855 Ciera Sunbridge
    Richmond, BC

    #2
    scope enough for the "expected" depth.... usually a scope of 5 to 1 is plenty good, but in strong current or heavy wind, more is better....in extremely calm conditions, any more than 3 to 1 scope is useless, and sometimes shorter can be even better.

    you also need to consider the tidal flow direction.... 7 to 1 scope in 20ft depth of water is a 280ft radius of swing you boat will have, and if the tidal current shifts 180 degrees, it will use the full 280 foot of radius, UNLESS you have a stern anchor or stern tie, in which case the boat will have very little lateral movement in any direction....... if the boat is allowed to swing on the changing tide or wind, its possible for the anchor to break out and allow you to drag it til the boat becomes grounded or beats against the rocks...........


    NU LIBERTE'
    Salem, OR

    1989 Bayliner 2556 Convertible
    5.7 OMC Cobra - 15.5x11 prop
    N2K equipped throughout..
    2014 Ram 3500 crew cab, 6.7 Cummins
    2007 M-3705 SLC weekend warrior, 5th wheel
    '04 Polaris Sportsman 700 -- '05 Polaris Sportsman 500 HO
    Heavy Equipment Repair and Specialty Welding

    Comment


      #3
      My experience is that you rarely use the entire length of chain. I have 300 feet of chain and I have never used more than about 150 or so. During normal tide changes when in a cove, I've done about 30ft swing from my set anchor in any direction. I have an anchor alarm that I set on my GPS so that if I get outside of a set circle it wakes my ass up at night... but I never had to use it.

      The weight of the chain itself will act as an anchor and you will rarely have to rely on the actual anchor. This all goes out the window if you have high current, high winds and soft bottom that you can't set your anchor in... in that case no amount of chain will work.
      Ships n Giggles
      1993 Bayliner 4388
      MMSI# 367412710
      Day Island Yacht Club
      Commodore

      Comment


        #4
        In BC it appears to be that the use of a stern tie is very common. It’s pretty easy to see if there’s an expectation, if the other boats are using shore ties or stern anchors, I strongly recommend you do the same. If there’s a bunch of yelling and arm waving that starts as you are dropping your anchor, it’s likely that you are about to set yours on top of theirs. That’s generally considered bad form. I agree that a seven to one is a bit much for most sheltered anchorage’s. I usually go between four and five depending on how the set feels. That’s a practice thing. A big help is an anchor bridal. Center to your rode, ends to cleats and let it take the strain instead of your anchor roller. It also improves the mechanical advantage of your rode. So, where are you going?
        P/C Pete
        Edmonds Yacht Club (Commodore 1993)
        1988 3818 "GLAUBEN”
        Hino EH700 175 Onan MDKD Genset
        MMSI 367770440

        Comment


          #5
          Originally posted by Pcpete View Post
          In BC it appears to be that the use of a stern tie is very common. It’s pretty easy to see if there’s an expectation, if the other boats are using shore ties or stern anchors, I strongly recommend you do the same. If there’s a bunch of yelling and arm waving that starts as you are dropping your anchor, it’s likely that you are about to set yours on top of theirs. That’s generally considered bad form. I agree that a seven to one is a bit much for most sheltered anchorage’s. I usually go between four and five depending on how the set feels. That’s a practice thing. A big help is an anchor bridal. Center to your rode, ends to cleats and let it take the strain instead of your anchor roller. It also improves the mechanical advantage of your rode. So, where are you going?
          Port Graves Bay on Gambier Island.
          "Binti B"
          1996 2855 Ciera Sunbridge
          Richmond, BC

          Comment


            #6
            Like centerline eluded to, I usually go 3:1 in a calm anchorage . The more chain you have the better. If heavy wind is expected then a 5 or 7:1 may be necessary. I use a kedge if high wind is expected and maybe go 5:1. Keeps the anchor more parallel to the sea bottom.
            Dave
            Edmonds, WA
            "THE FIX"
            '93 2556
            Carbureted 383 Vortec-Bravo II 2.0:1 18 1/4x19 P

            The rebuild of my 2556 https://www.baylinerownersclub.org/f...76?view=thread
            Misc. projects thread
            https://www.baylinerownersclub.org/f...56-gctid789773

            Comment


            • Centerline2
              Centerline2 commented
              Editing a comment
              we know exactly what you mean, but its spelled "K-E-L-L-E-T" .... a very good thing to have handy at times when one uses a nylon rode on short scope, like in a crowded anchorage...

            • builderdude
              builderdude commented
              Editing a comment
              Ah yes, kellet. My bad 🥴
              I used a 10# cannonball shackled to my short chain.

            • Metrodriver
              Metrodriver commented
              Editing a comment
              what is a kedge?

            #7
            Here's an interesting article regarding the use of a kellet.

            http://cruising.coastalboating.net/S...lletFacts.html
            Rick E. Gresham, Oregon
            2850 Bounty Sedan Flybridge model
            Twin 280 HP 5.7's w/ Closed Cooling
            Volvo Penta DuoProp Drives
            Kohler 4 CZ Gen Set

            Comment


              #8
              The scope should be for the maximum expected depth. There are times in a tight anchorage that this is not possible and you may need to decrease scope as the tide goes down. Scope is measured from the waterline and not the anchor roller. A boat with a combination rode (chain and rope) will often need more scope.
              1999 3788, Cummins 270 "Freedom"
              2013 Boston Whaler 130 SS
              Anacortes, WA

              Comment


                #9
                Originally posted by Norton_Rider View Post
                The scope should be for the maximum expected depth. There are times in a tight anchorage that this is not possible and you may need to decrease scope as the tide goes down. Scope is measured from the waterline and not the anchor roller. A boat with a combination rode (chain and rope) will often need more scope.
                im not the expert on the subject, but I would think the scope should be measured from the anchor roller.... the anchor roller may be 4-6 feet off the surface of the water, in which case at a15ft of depth of water becomes 20ft to the bottom from the roller.... a 25% increase, which could make a difference in the amount of line you let out in difficult conditions...

                but I also agree that its not rocket science, and a few feet, give or take, makes little difference in normal conditions..... on a good holding bottom with a well matched anchor, 3:1 is going to hold you in all but the very worst storm conditions.... and a 7:1 scope is almost always overkill in all but the very worst storm conditions... so anywhere between the 2 is enough scope for most normal anchorages, even when using a substandard anchor.....
                but when one drops their anchor on an unknown bottom, they can never knows what to expect, and if the anchor cant grab the bottom, a 10 or 12 to 1 scope wont help anything, and if the bottom is littered with rubble, a 2 to 1 scope could hold you to the seabed until the anchor roots up the car sized boulders its hung up on, in which case you may never see your anchor ever again...

                its my opinion that its more important to know how to read the anchorage and know how to use the ground tackle, than it is to simply drop the anchor, let out the estimated scope, and pretend you have done all that is humanly possible to keep your boat firmly anchored if the wind or current should pick up.... hence; the art (skill) of anchoring...


                NU LIBERTE'
                Salem, OR

                1989 Bayliner 2556 Convertible
                5.7 OMC Cobra - 15.5x11 prop
                N2K equipped throughout..
                2014 Ram 3500 crew cab, 6.7 Cummins
                2007 M-3705 SLC weekend warrior, 5th wheel
                '04 Polaris Sportsman 700 -- '05 Polaris Sportsman 500 HO
                Heavy Equipment Repair and Specialty Welding

                Comment


                • Sunbird
                  Sunbird commented
                  Editing a comment
                  Scope is measured from the anchor roller- on larger boat distance from roller to water surface can be quite a bit. It’s also very helpful to have the rode or chain marked at 30 ft intervals so you know exactly how much you have out.

                #10
                Setting out your rode correctly is just as important. Make sure that you are backing away from the anchor whilst laying out your rode. It won't do you any good if your 5:1 is all in a pile on the ocean floor.
                SeniorEta 1993 Bayliner 2859 7.4L

                Comment


                • Centerline2
                  Centerline2 commented
                  Editing a comment
                  absolutely... or all in a pile wrapped around the now fouled anchor....

                #11
                Well I'm sitting at anchor right now, enjoying the evening. Crunching depth and tide numbers while standing on the fore deck with the rhode in my hand was interesting, but I kinda felt the anchor dig into the bottom the second it touched down, and we've been here most of the day. Roughly 5:1.

                In the morning I'll see about pulling it up again.
                "Binti B"
                1996 2855 Ciera Sunbridge
                Richmond, BC

                Comment

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