Are You Sailing with 'Weak Links' in your sailing rigging?

by SkipperTips.com on 15 Aug 2014 With the wind howling and the seas building--and hundreds of miles offshore--we had a serious problem aboard. A critical rigging pin had backed out--with just an eighth of an inch of thread to hold the fitting together. We needed a solution now--and fast. What now skipper?

Screw pin shackles are often forgotten parts of your boat's standing rigging and anchor ground tackle system. Here are just a few ways this super sailing gear works aboard your boat:
• Bend a mainsail or headsail halyard to your sail
• Attach sheet, turning, and snatch blocks to a rail or deck eye
• Tack the Genoa or staysail to the deck
• Link one part of your anchor ground tackle to another
• Hold standing rigging in place (permanent or in an emergency)
• Make up the ends of a boom vang, preventer, or topping lift

Stainless or Galvanized screw-pin shackles can fail from shock or vibration. And if those shackle pins back out too far, your shackles will fail.

In the case of your anchor ground tackle, your marine anchor will end up on the bottom--and you could end up on the rocks!

In the case of standing rigging, a failed shackle could cause a shroud or stay to fail and the mast to fall over (dis-masting).

'Remove the Load Before You Fix a Fitting!'

Look at the photo above. This shows the actual sheet block in our opening scenario. This huge 3' stainless shackle was being used to hold the sheet block on a 53' ketch with its Genoa sheet under heavy load. The stainless pin had backed out of the body and was being held by a mere sliver of thread.

To make a fast temporary repair we tightened the shackle pin as much as possible. Then we tacked to remove the load from the fitting. Without a load on the fitting, we were able to tighten the pin all the way.

To further secure the pin, we lashed the pin to the shackle body with a plastic wire tie (see tips below). Then, we tacked back to our original sailing course.

This simple repair took just a few minutes. But, if we had not caught it in time, this block could have become a 'lethal weapon'. Follow these three super simple sailing tips to keep your standing rigging and anchor ground tackle robust and secure:

1. Beware of Stainless Screw-pin Shackles
Assume right off the bat that stainless screw-pin shackles will not hold together without help. As in the opening scenario, vibration will cause these slippery pins to back out.
Make a temporary lashing with plastic wire ties with all stainless screw-pin shackles aboard. Pass the wire tie through the screw pin hole, then around one side of the body and back through itself as described earlier. This will give you peace-of-mind and prevent unexpected rigging problems.

2. Maintain Galvanized Screw-pin Shackles
Check to make sure that the pin in each galvanized shackle turns without binding. After months of disuse, pins tend to corrode inside the screw channels (grooves). You need to be able to remove those pins to change shackles or service the fitting.

Open each shackle with pliers. Wire brush the threads, apply a waterproof lubricant, and screw the pin back into the shackle. Use plastic wire ties to mouse the pin to the shackle body. For a more permanent (and saltier) solution, mouse the pin with stainless seizing wire (see below).

3. Mouse the Pin for Strong Security
Use the more permanent technique called 'mousing' when possible. This nautical seizing secures the pin with wire from the hole in the head of the shackle-pin to one side of the shackle body. Use stainless steel seizing wire for strength and durability.

How to Mouse a Pin to a Shackle Body?
1. Cut off an eight inch length of stainless seizing wire. Hold two inches of the wire next to the shackle body with your thumb (illustration 1 - far left bitter end). Wrap the other end around the body and back through the screw-pin hole.
2. Continue to weave the long end of the wire around the body and back through the hole. Keep the turns butted up next to one another. Stop when you have two inches of wire left (illustration 2).
3. Twist both bitter ends together with needle nose pliers. Cut the twisted wires off to ½'. Push the twisted ends up against the screw-pin (illustration 3). This protects the wires from wear and chafe.
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Boost any anchor shackle's integrity when you mouse the pin in place with these three easy sailing tips. This will give you peace-of-mind that your sailing rigging and anchor ground tackle will keep you and your sailing crew safe and secure in any weather - wherever in the world you choose to sail!