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Old 03-06-2010, 20:27   #1
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Rope Ratlines ?

Does anyone have any experience with rope ratlines? I'm thinking about installing ratlines and I'm not wild about adding the teak rat-"steps" for fear of adding too much additional windage. Would the flex of the rope and the inward tension on the shrouds cause damage?

How are they affixed to the shrouds? What knot or other technique is recommended?

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Old 04-06-2010, 03:09   #2
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I believe the Clove Hitch was commonly used to secure Rope Ratlines to the rigging.

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Old 04-06-2010, 15:51   #3
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You can use rope, wood, or steel for ratlines/steps. It all depends upon the size of the boat and the rigging. Without knowing the specifics of your boat as to size, rig, lower shroud spacing, height of lowers, etc. it is difficult to recommend anything. Additionally the style of the boat and rigging makes a difference. Old square riggers with hemp and block stays and shrouds are different from 1x19 stainless which is different from rod rigging.
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Old 04-06-2010, 17:48   #4
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I would hesitate to do this on 1x19 shrouds, just because of the point bending in an inflexible cable. Then again, lots of people hang a hammock off of their forestay.

The benefit of "rat-steps" is that they are rigid, which transfers the force directly to the stay. Rope ratlines pull sideways on the stay. This magnifies the tension force necessary within the stay to keep you from falling. I don't imagine this would be a problem on a boat with 1/4" shrouds or larger. Anything smaller than that and I would be scared you may stress the cable unduly.

Also, if you insist on the rope ratlines, it would minimize the load on the cable if you kept them loose. Remember, line only works in tension while wood works in compression and tension.

Here is an illustrative example.

Let's say your mass is m=100kg.
Assume gravity is g=10kg*m/s^2
Lets assume you are in a hammock. If the lines from the hammock meet the tree at a 45 degree angle:

1000/0.7071=t/1=1414 N

The tension on the line is 1414 N.

Okay what if the hammock is really tight and the lines meet the tree at 20 degrees?

1000/sin(20)= 2923 N

Now what if the hammock is super tight and the lines meet at ten degrees?

1000/sin(10)= 5759 N

If we extend this thinking a little, we can apply it to your ratline question.

Instead of a hammock, lets say you have a ratline with your weight on it.

Instead of trees, lets say that you have shrouds.

Now it should be clear why loose ratlines will put less load on your shrouds.

I would use a double constrictor knot if I were doing it on your boat. I wouldn't do it on my boat though!

A pinrail, maybe.
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Old 04-06-2010, 18:10   #5
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The traditional way of doing ratlines was to splice an eye in each end of a piece of small line. That line was then tied in a clove hitch around the shroud in the middle, and the eye on each end was seized on the outside shrouds.
However, the shrouds were usually wormed parceled and served before the ratlines were seized on. It would be difficult and time consuming to make seizings on 1x19 that would hold. Not impossible though.

I agree. I have never liked to see people hanging hammocks off their forestays on wire less than 5/6"or 3/8".
I know that a good way to tension a loose shroud is to bend a line to it and pull it aft with the sheet winch.
I don't think people realize how much force you can impart by pulling sideways.
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