The Catamaran Adventures of Noel and Ceu
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Adding Depth Markings to Anchor Chain

One of the fundamental keys to effective anchoring is to use the correct length of anchor chain (called the rode) for the depth of the anchorage. Too little and you may end up dragging your anchor. Too much and you might swing into the other boats in the middle of the night when the wind or tide changes.

This ratio of length of rode to depth of water is called the scope. The normal ratio (scope) that one would use is 5:1 if the anchor rode is all chain or 7:1 if the rode is nylon. In poor holding conditions or stormy weather, one might increase these ratios in order to get a more secure hold.

But, the big question is, how do you know how much rode you have laid out? As the chain whizzes past you as the anchor drops into the depth it is almost impossible to estimate how much has gone by.

The answer is, of course, to put markings on the chain.

So that is exactly what we did for the brand new chain on our boat.

Here in the photos you can see how we laid the anchor all around our decks, put plastic bags beneath them, and painted them with an oil-based enamel intended for metal. However, since we couldn’t get a white enamel paint, we also used a spray paint intended for outboard engines. You can see that part draped over the lifeline to the left. It will be interesting to see which holds up better.

To make it really easy to identify depths, we used three colors: red, white and blue, which we used in sequence every 10 meters. Why 10 meters? Because it is also approximately 30 feet, so it makes it easy to use the markings whether the depth is measured in feet or meters, whereas if we did a mark every 25 feet, it would be hard to convert to meters, and also hard to interpolate for intermediary depths.

So, using these colors and markings, it is very easy to set the correct amount of rode. Suppose for example that we are in 17 feet of water. Multiplying that by 5 gives us 85 feet, which is almost 90 feet. So we let the anchor windlass run until we see the blue marker coming up. Similarly, if we are in 3 meters of water, that gives us a scope of 15 meters, which is half way between the red and white markers.

The other thing we did is to make the paint markers a couple of feet long. Again, this makes it much easier to see as the chain is zooming past.

One unexpected bonus of the white paint, at the 20 meter mark, is that it is really easy to see in the water, so you can see what direction the chain is lying in.

4 Responses to “Adding Depth Markings to Anchor Chain”

  • Hi:
    Nice log.
    We are getting a Lagoon 450 next April, picking her up in France. We will sail the Med summer 2012 before crossing to St. Lucia with the ARC. Our boat’s name will be NextLife.

    About you chain markers. I did the same principal on my current 40-foot monohull (10meters~30feet), except with coloured vinyl markers from West Marine sewn to the chain. How is the paint holding up?

    • Noel:

      Hi Rolf

      That’s a big boat you are getting! And an interesting name for her 🙂 Is it just two of you onboard?

      We will probably be crossing to the Caribbean next fall too, but not with the ARC. They usually leave the Canaries about November, so maybe we will bump into each other somewhere in the Med or going south.

      The paint doesn’t work. We have tried several different kinds of paint, but it quickly wears off.

      On the other hand, the little plastic markers that fit into the chain work very well. But we have trouble finding them in the chandlers, so we keep picking up a bag here and there when we can find them.

      Happy sailing,

      Noel

  • Joe Donnaway:

    Rolf, Noel;
    I’ve used colored cable ties to mark our chain – Green, Yellow and Red. One tie per chain link holds up reasonably well coming through the windlass, and are easy to replace. One green at 25′, two at 50′, three at 75 feet and four at 100′. Repeat with yellow for the next hundred feet. Then red – I have 250′ of chain, so we end with two red ties.

    Safe Sailing,
    Joe

  • heidi:

    Aall a bit technical

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