By now you should be familiar with my standard shackle described in:
How to make a 300% Shackle by Walt Spang
The reason I wrote the first part was; the standard shackle has very similar construction to the “TOUGH GUY” shackle.
Before I forget again; I use
New England Ropes exclusively for my shackles. I just prefer it. Has a higher advertised breaking strength than
Samson.
Start by cutting a length of
Dyneema the size you want to use for your shackle. Add extra length to allow for a longer tail. If the length of the shackle is 16” from base of
knot to the end of the loop you want the
knot tails to pass the loop somewhat. You’ll decide on a good length with practice, so you don’t waste more
Dyneema than you must. Next fold the length of line in half like previous. Mark where the knot will start like previous. Marking both sides together. Next place a mark down from the knot mark 2-3” on both halves. This is where you will start and stop the bury to the loop.
Measure and cut a length of Dyneema one size down from the material your making the shackle from. (1/4 cover,3/16 bury as an example). This time do not taper one end but bury the line from mark to mark (not the Knot start marks). Leave extra length on the bury line to be able to grab and pull during construction.
Now create your loop just like described for my standard shackle but leave the bitter ends out and don’t taper them.
Build your button knot. Make it as tight as you can during the building. I use a
steel working scratch awl tool to get as much leverage on the strands as I can making the knot for ¼” shackles. And a regular pick for smaller.
When you’ve completed the knot; layout the knot tails side by side with the shackle body. Place a mark on each tail about an inch out toward the loop from where the marks are on the body that you started and ended your bury.
You are now ready to begin the overlapping portion of the build.
On the shackle body measure down 8 inches from the bury marks toward the loop and mark both sides of the bury. If it reaches the cross over point or beyond, place the marks further back. Remember the longer the overlap, the stronger the joint should become.
When you bury the tails you will have to use a smaller fid in order to run it alongside the already buried line.
Next take one of the tails from the knot and pull out a strand from the line at the mark you made on it. Pull out a second strand about ½” further down from the first toward the bitter end. Cut them off flush.
Go down now toward the end of the tail but beyond where the tail will
wind up being buried and start removing 3 more strands as you get close to the end to form a taper. By now there should be enough strands removed to stuff the end into the back of the Selma fid. I use the scratch awl to cram it in so it doesn’t pull out easily. The fid has a built in hook to grab the brades but there basically aren’t any at this point. I use
electrical tape to wrap my lines. I prefer it over masking tape. If the stuffed end comes loose sometimes it get hooked and you can continue to pull the line through the cover. Good luck with this and be sure to have patience.
As you
work the fid along, pulling on the smaller line that is buried can help. What happens now is the cover will bunch up all the way back to the pierce on both side as you make the knot This something to keep in mind and I will explain. Note: On the side that goes through at the crossover I pierce the line on the knot side of the crossover making sure to also go thru the buried line. Otherwise the bunching up goes around the loop and is a bear to
work it out. I will explain the reason to ensure a tight cover and bury later.
After you come out at the second mark; pull the line through the overlap section up tight against the knot base. The buried tails must be pulled tight. If not it will bulge out later during the knot tightening process.
Now begin kneading the overlap area milking back and forth, back and forth to tighten the cover and the buries as best you can. Be sure the loop area is good and tight.
After you’ve done all this; perform the same tasks with the other knot tail. Take your time, have patience.
After you have completed the tasks, stop, have a drink or
beer or two or more. LOL
It is now time to begin tightening everything up. You have what looks somewhat like a completed shackle with 4 ends sticking out. What we are going to do now is pull the shackle and here is what can make or break your 300%.
I made a jig to put the shackle through and hold the knot. The loop end I place in a hook. I then attach the jig end to a line and run it to one of my manual winches.
Take your shackle and soak it well in
water. Have it dripping and pull it using what device you come up with.
HERE IS A SECRET THAT IS GOOD TO KNOW. Dyneema has a very low melting point. Heat will weaken it tremendously. The
water helps lubricate the strands and draw off heat from frictional forces. Also remember to just pull a little at a time, again to allow heat buildup to dissipate. Pull the shackle enough to tighten cover and bury uniformly. The fatness of the overlap will shrink down and the ends will get pulled in. (Not all the way LOL). Now take the shackle and mark where the ends come through the cover Pull on the ends to pull out a length on each. You won’t get much out but get what you can. Cut the ends off behind the marks and make as long a taper as you can. Now milk and pull etc. to rebury the tapered ends.
Now it’s time to tighten the knot. Re-soak the shackle and place back on your pulling device. And now pull that puppy as hard as you can. BUT DO IT SLOWLY AND A LITTLE AT A TIME. Allow for the heat buildup to dissipate between pulls. Don’t worry about overtightening the knot. Chances are you can’t.
Remove the shackle, dry it and you now have a 300% shackle.
Note: My shackle pulled to 300% without the first soaking pull. I pulled it dry. When I performed a post mortem on the shackles I decided to also pull the first pull wet.
The two buried lines form a like a fault such as in
California. When the pressure gets great enough the fault ruptures or slides and you have an earthquake. The same with the buried lines.
So, adding this extra soak may bring your shackle even higher than 300%. I’ll keep you informed since I will be testing another batch shortly.
Walt Spang
S.V. Sail’n Somewhere