The idea of this is to take some of the stress away from the knot (the only built in weak link on a tow line) by putting two turns of the line round a large diameter tube before the line is knotted.
I have used this form of ring for seasons and the increased strength gained from any tow line is quite considerable. The finer points of tow line selection will be dealt with in a future issue, but basically the thinner (lower breaking strain) line that can be used without breaking the better.
Fig 3 shows the materials to make one ring--1/2" of approx 1/4" in diameter brass tube (note how it has been slightly flattened into an ovall shape) : 7/16" of 1/8" in diameter tube and about 3" of bowden cable. A free supply of the latter can be obtained by polite request of your local cycle repair shop.
Slide both the tubes onto the bowden cable, Fig 4, and form the cable into a loop. Push both ends into the smaller tube untill they protrude slightly, Fig 5, and crimp the smaller tube, sliding the larger tube over the top, Fig 6. Seal one ond of the larger tube with tape and fill it with epoxy, Fig 8. Definitely one of those items it takes longer to write about than make!
Now For The Other End - The Winch
Fig 9 shows the drum with one side removed. Note:- The centre has a slice removed. The winch drum sides are made from 1/8" birch ply and are 8" diameter. The centre is 4" to 4 1/2" in diameter and between 5/8" and 1/2" thick as any wider will tangle the drum.
Fig 10 shows the line passing through a hole in the side of the drum and secired under the head of a self tapping screw. Wrap four turns round the drum and put in the locking pin - a 3/8" diameter brass tube which is a push fit in the drum sides and held in place with tape. This method takes the stress away from the point where the line is secured.
And Finally - The Knot
Fig 11 shows the knot I use when fishing. It is known as a Grinner Knot. It is best to practise with string rather than struggle with springy nylon untill you have worked it out. When pulled tight it should look neat with the the turns of the line fitting snugly together.
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