What should I use to seize anchor shackle

[lw395]

As a modest 'aside', the Harbourmaster at Fowey - who is responsible for the several hundred moorings there - pointed out the problematic practice of yotties winding a nut onto an anchor or mooring shackle as tight as a big wrench can get it. "Some even use a long extension bar," he said. "That adds nothing whatever to the strength of the fitting. In fact, it weakens it, for over-tightening scrapes off the galvanizing microscopically where the male ( pin ) thread and the female ( nut ) thread interlock. Corrosion starts there immediately, and spreads progressively under the adjacent galvanising. That can half the expected service life of a good mooring shackle. So," he advised, " do a nut up firmly, no more, then lock it with wire or cable ties. Inspect it at least twice a year."

FWIW....

Sounds like drivel to me.
More corrosion happens through stuff moving and wearing off the oxide layer.
Two galvanised surfaces will actually weld together. galvanising works like an anode, so is not prone to corrosion getting under it like say chrome plating.
Anything locked with wire is prone to cretin sailing schools lassoing the buoy and pulling the wire off.
A cable tie has limited strength.
If you are going to mouse shackles and rely on it, use something pretty stout. The thickest plastic coated garden wire is quite good.

 

[Neeves]

I think Oldbilbo's suggestion of constant attention to the shackle is key, in the same way you should be checking that block shackles remain tight one ought check the anchor shackle - it does not seem too difficult to check it every time prior to deploying the anchor - and if anything looks iffy, change it. Siezeing wire, cable ties, a new shackle should hardly break the bank.

We anchor very frequently and have had success with cable ties (we would use 2, one over the other - but being in Oz we do not need socks), but are currently using (for the shackle) copper wire, stripped from domestic cabling (as previously posted) but have also used plastic coated stainless steel wire (fishing trace).

Jonathan

 

[Amulet]

Cable ties have become the standard, and I know from a commercial provider of moorings that his liability insurers actually specify cable ties. I have never actually seen a shackle work loose in that environment (but there's always a first time). In my experience they tend to weld themselves closed. (I have seen a shackle break though.)

 

[William_H]

Cable ties have become the standard, and I know from a commercial provider of moorings that his liability insurers actually specify cable ties. I have never actually seen a shackle work loose in that environment (but there's always a first time). In my experience they tend to weld themselves closed. (I have seen a shackle break though.)

A shackle on an anchor or mooring is very susceptible to unscrewing itself. All it takes is repeated jerking with a load slightly off centre that tends to rotate the pin. Considering the boat has nothing else to do all night (and day) bu to try to escape it soon gets a shackle pin undone. So stout mousing is vital as is firm tightening. As said any movement quickly wears with corrosion so pin needs to be so tight that it will not move in the thread then mouse for safety. Hopefully with GI shackles after a while rust will seize it solid and there is no chance of undoing it. By you or nature. olewill

 

[oldbilbo]

".....Sounds like drivel to me....."

Captain Paul Thomas has significant experience of anchoring and mooring matters, having been responsible for the maintenance and security of 900-odd moorings at Fowey for quite some years - and a professional career in commercial shipping worldwide before that.

"The Harbour Commissioners own approximately 900 moorings and rent them under annual contract to the licensees....."

In our discussions, his perspectives were well-reasoned and based on what seemed to me to be a more-than-adequate depth of experience. While I'm always interested in other informed opinion - a primary reason for reading much of the 'drivel' that appears here from time to time - I've read nothing yet that persuades me that Captain Thomas has got it wrong. But do take it up with him - I'm sure he'll be interested to hear your views....

 

[Amulet]

A shackle on an anchor or mooring is very susceptible to unscrewing itself....

Despite never having seen it, I am willing to believe that the first one I don't mouse will prove me wrong. I put the biggest cable tie I can fit through. As a matter of fact, cable ties, sikaflex, WD40 and duct tape can solve any marine problem.

 

[alahol2]

I've never understood those who specify galvanised shackles for use underwater on moorings. The first thing that happens is that the galvanising is eroded and falls off. You then have a pin which is loose in the thread and the shank. Often, after several months, the only thing holding the pin is the mousing. I have always used black iron shackles and they have always stayed tight on the thread. The shank end of the pin does gradually wear the hole in the shackle bigger. I normally mouse with monel plus one or two cable ties.

 

[vyv_cox]

Many moorings on the Menai Strait have no shackles at all, my contractor uses welded links of rebar. Despite that, one of mine failed.

 

[RAI]

Despite never having seen it, I am willing to believe that the first one I don't mouse will prove me wrong. I put the biggest cable tie I can fit through. As a matter of fact, cable ties, sikaflex, WD40 and duct tape can solve any marine problem.

You forgot PTFE tape, useful in plumbing applications, but also around galvinised shackle threads for that added non corrosive friction additive that also permits easy undoing. (I still mouse with monel metal wire).

 

[Bosunof]

I have stuck with Monel. Has done me OK for 7 years or so.