Mooring chain connection

[Tandem]

I want to create a back-up mooring chain for a swinging mooring.
Primary strop is a 20mm octoplait soft loop to boat and hard eye to a 22mm certified bow shackle onto the buoy swivel, minimum size 'allowed'.
Proposing to use 10mm chain, with a shackled loop to a cleat on the boat, but not clear how I should join the chain to a 22mm bow shackle without losing integrity....
Any suggestions appreciated.

 

[Kelpie]

Is the problem that you can't get a shackle to fit both the 10mm chain and the 22mm shackle? In which case you could increase the size of the chain, or use a second shackle. A second shackle does add a potential failure point, but if it's properly moused it's not really a worry- and being on top of the buoy it would obviously be easy to inspect.
Could you fit the chain directly to the buoy, rather than the shackle? Slightly more redundancy that way.

My only concern about having a backup strop is in case it chafes on your multiplait.

 

[Neeves]

If cordage is sufficient for the primary mooring why do you feel the need for chain for a back-up?

Jonathan

 

[Tandem]

Is the problem that you can't get a shackle to fit both the 10mm chain and the 22mm shackle? In which case you could increase the size of the chain, or use a second shackle. A second shackle does add a potential failure point, but if it's properly moused it's not really a worry- and being on top of the buoy it would obviously be easy to inspect.
Could you fit the chain directly to the buoy, rather than the shackle? Slightly more redundancy that way.

My only concern about having a backup strop is in case it chafes on your multiplait.

Yes, chain size is the issue. Second shackle is an option I was considering. I am making a loop in the chain at the boat and had considered making a second loop for the chain to the bouy swivel, but was not sure if that was an acceptable method. Chafe is a concern, but if I remove the anchor I can use both rollers on the bow...

 

[Tandem]

If cordage is sufficient for the primary mooring why do you feel the need for chain for a back-up?

Jonathan

A requirement of the club. Mooring location is adjacent to a busy shipping lane and there have been issues with boats breaking free - due to chafe and vandals - requiring a secondary and less vulnerable back-up.

 

[Daydream believer]

Rather than put the pull directly onto the shackle ;which may be too small to fit the chain & the buoy; Pass the chain through the loop of the buoy & back on itself for 150mm & shackle it. Then put another shackle at 75mm. Sometimes the chain links are too small for a shackle pin to go through in the middle of the chain. In that event put the largest shackle you can at the end of the chain & having gone through the buoy put the shackle OVER the chain rather than through it. You will often find it will bind on the loops.If not, then it will slip down to form a tight loop on the buoy ring .It is far from ideal but as you have said , it is for emergency when the rope wears through. There is nothing to stop you passing the chain through the buoy ring twice first, if there is enough room.

 

[lw395]

A requirement of the club. Mooring location is adjacent to a busy shipping lane and there have been issues with boats breaking free - due to chafe and vandals - requiring a secondary and less vulnerable back-up.

I think I'm capable of eliminating chafe, eliminating vandals would probably be frowned upon.
If you need to have chain, why not see if having the chain as the primary mooring strop works OK?
I was never happy with it on my boat where I moored but your situation will be different I expect.

But in my experience, moused shackles are more unreliable than any other thing on a mooring.
I tend to replace the pin with a HT bolt, torque it up with locknut, threadlock and drill through the locknut for a split pin.
The pro's around here weld their shackles. I get them to do that for those underwater I can't inspect frequently.

 

[Daydream believer]

The problem with chain for the principle mooring is that it can chaffe on the sides of the roller & wear the cheeks quite rapidly. If it is a small boat with no roller but just a gunmetal guide ( like my Squib)this can be quite marked . This can snag lines such as spinnaker sheets & the spinnaker itself causing rips . It also can "jerk" a bit. Rope can be a bit more gentle . The chain then becomes a safe backup. One should always have a backup, whatever one uses.

 

[Tandem]

Thank you all for the advice.