Maximum load on mooring tackle

[wallacebob]

Araldite applied liberally to shackle pin threads on install helps reduce corrosion: several experiments on Forth moorings . Still must seize the pin as well . These are drying , so this is do-able. They still wear tho’, so annual inspection essential.

 

[eddystone]

My experience in Poole Harbour maintaing moorings at our club for the last 20 something years is that shacke pins are what fail. The tread on the pin just disappears and the pin drop out. We wire all our shacke pins with seizing wire.
If anything is going to fail it will be the shacke one side or the other of the swivel at the top of the riser.

That’s why I use nut and bolt type secured with a split pin

 

[Refueler]

Araldite applied liberally to shackle pin threads on install helps reduce corrosion: several experiments on Forth moorings . Still must seize the pin as well . These are drying , so this is do-able. They still wear tho’, so annual inspection essential.

My thoughts are you are reducing the salt water aspect maybe - but corrosion is already there before item is used or coated.

 

[NormanS]

When I laid my moorings, firstly for a heavy 60ft vessel, and latterly for a 36ft ketch, the shackles that I preferred had screw pins. I would throw away the pins, and use a bolt with the same thread, plus a nut, plus a split pin. The bolts were normally 24mm or bigger. It may sound counter-intuative, but I always gave the threaded parts a generous coating of Coppaslip. They didn't fall apart, come loose, nor did the threads rust or deteriorate. When required, the shackles could always be undone.

 

[boomerangben]

In subsea construction we only ever used bolt type bow shackles because they were considered the safest option. Screw pins shackles were consigned to the bin, pin and all. D shackles only ever used to join two bits of chain. The key to shackles is making sure their geometry and dimensions were correct, along with WLL of course

 

[Neeves]

In subsea construction we only ever used bolt type bow shackles because they were considered the safest option. Screw pins shackles were consigned to the bin, pin and all. D shackles only ever used to join two bits of chain. The key to shackles is making sure their geometry and dimensions were correct, along with WLL of course

If you look at reputable shackle maker's websites you will find there are increasingly complicated, and secure, designs for shackles in critical applications. I'd have said - motivated by the oil industry. The simple shackle is of increasingly complicated engineering.

Ours, mooring application, are welded. There is commonly no need remove the shackle pin once the mooring is assembled. The 'used' shackle is simply cut off. The shackle pins are secure - no need to overtightern, no need to use mousing wire, no need to use Loctite.

They are welded.

Not to be mistaken for anchor shackle usage - different application and demands

Jonathan