Tuesday, December 04, 2012

Building a yacht mooring - ground tackle overkill

 Our mooring is taking shape and now it's time to assemble the mooring chain.  Luckily we could purchase quality American and Canadian made shackles for cheap at a local industrial fishing supply warehouse.
 This big boy 7/8" safety shackle has a working load of 13,000 pounds and a break strength in excess of 65,000 pounds.  Since the bottom is soft and the mooring block will become buried in mud and silt over time this shackle will become near impossible to inspect and thus knowing that it's way bigger than necessary will ensure long term value.   This shackle will connect the mooring to the ships chain.
1-1/8" stud link chain.  The links are 6-3/4" long and it weighs about 12 pounds a foot. I can't think of anything more perfect for the job of ground chain to provide the cushion of catanary in a big blow.  This will form the ground chain element of the mooring system.  Ideally we'll be using 60'... if we can find a way to move that much weight.  When new this chain would have a breaking load of over 100,000 pounds!  Even though this is pretty old chain it's still insanely strong.

The big chain is then attached to a 3/4" thick by 9" long swivel.  The swivel could wear over time so again we're going oversized.
Moving back toward the reality, these are mere 5/8" safety shackles with a working load of 6,500 pounds and a break strength of 32,500 pounds.  Note the nut and cotter pin on the end of the pin.  These shackles form the link between the swivel and the top chain.

 Next is the top chain which at 5/8" thick with 3" long links.  I has a working load in the range of 6,800 pounds.
Huge pile of 1-1/8" old ships chain.  Dragging a piece of this chain off the pile to use as our mooring ground chain was one of the toughest parts of the entire project.

For more on the mooring build check out these prior posts.