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Went to the local RTM shop here chatting too a yachtie got talking boat mooring lines and fittings, he told me braided line as little a 200 k breaking strain would hold my girl in a storm, so with that I thought 1600 kg breaking strain will do me so picked up 30 meters of braided line, my 10 mm swivel looked cheesy to me so a 16 mm swivel which is almost as heavy as the boat will do, 2 ton rated shackles.
im still stumped on couple things, the chain that attaches to the block itself he recommended 10 mm chain , that sound ok? And how do you attach the line to the swivel, he said tie it, I thought me and knots and actually pulling of a knot that would secure it, which knot would I use? I still like the idea of doubling the rope,
Hey mate, I'm in exactly the same situation. Setting up a swing mooring with new pennant.
Mine is 5ton so I'm going with 16mm 3 strand nylon. I'm still trying to find out what the breaking loads of the swivels are. They all seem to be RWB (brand) galvanised mooring swivels but I guess what has stumped me is how much load am I trying to accomodate? Obviously I'm not trying to pick the whole boat up but what are the loads on a swing moorings gear when it's a full gale or even a storm?
Line to shackle, is as I have seen through all this research, a cow hitch, so slice a loop, pass the loop through the shackle then thread the line through the loop, pulls tight but no chafe or splice a thimble onto the end and thread through the shackle.
What was the breaking load of the 16mm swivel you picked up? Do you know?
The pin in the swivel should be bigger in daimeter than the chain links to which you are attaching it.
I would suggest a nylon riser in 3 strand or braid spliced direct to the swivel. Use a piece of rubber or plastic hose instead of a thimble, have it long enough so that it comes back on itself and secure that with a strong electrical tie. Have enough rope pulled through the hose and splice that. Other side of the swivel attach that with a shackle to your bottom chain and mouse it with a couple of electrical ties or 2mm spectra. Use good quality chain on the bottom and cheap shackles that you replace regularly. Where you propose to have your mooring is subject to a very strong tidal flow and shortly there will be strong Westerlies and your vessel will be subjected to strong winds against the current. It will be sitting sideways to the weather and regularly sailing around your mooring. Ensure you have some abrasion resistant material over your riser where it comes over the bow roller. That blue fire hose is good. Make sure the bow area is free from sharp edges etc.
We are wary about cheap shackles in our mooring ground as cheapies have failed due to corrosion of the pin threads, which are often machined after galvanizing. Some of them are simply rubbish regardless, with very poorly cut threads which will never tighten properly, and the cost difference is insignificant in the overall picture.
The corrosion in the thread allows the pin to loosen and move around, and then it is reliant only on the mousing. Nylon cable tie mousing doesn't survive well in this situation either. They don't tend to fail in heavy conditions as the high forces tend to hold the pin in position. They mostly fail in in moderate to light conditions where things are free to rattle around, allowing the pin to rotate and drop out. So based on our experience, good quality shackles and wire (monel is best) mousing are preferred.
Cheers, Graeme
As for the breaking strain. The breaking strain or "Safe Working Load" is usually about a quarter of the load it will snap at. I have seen shackles rated to 500kg hold 1400kg and it didn't look like it was going to break.
As for 10mm chain, that is ok. I like to be overkill so I would go 12mm that way there is no doubt.
Sorry guys but you're creating under water batteries!!
Black chain, black swivels and black shackles only with no galv!!
I have found 3 strand to untwist even with a swivel as the swivel fills with crap quickly and doesn't rotate.
I use no swivel and 8 plait line, most boats don't do enough circles to bother it and it untwist as soon as you take the boat off.
It is harder to splice but easy to learn.
Speaking of which, current job splicing 40mm 8 plait for a fish farm!!
And yes this thimble is galv but it's in a low salinity environment and the rope wears out first anyway!
So many mooring threads ! I won't bore you with my construction details as its horses for courses. If your in a potential wind over tide situation, I recommend setting your buoy up like this, it gives plenty of opportunities to hook it, a knot before the onboard eye splice stops the buoy pendant pulling through and the buoy is easily lifted on board "after" the morning line is made fast. Buoy stays clean and more importantly doesn't bang away at your bow/ topsides!
A good mooring apparatus spec I came across is from across the ditch here; google
waikato regional council swing mooring report ocel
Hi all,
this may have been covered previously but if you make your own mooring apparatus and your boat comes off, for whatever reason, and creates damage to another boat or property, how does your insurance company view this??
There may be a lot of opinions regarding this issue and I know that construction of mooring apparatus and the qualifications of mooring inspectors is a dogs breakfast here in NSW, but has anyone asked their insurance company how they would view a claim for damage resulting from a amateur built mooring failure???
Mike
Thanks Ramona,
but that's not what I asked, my question was.
"this may have been covered previously but if you make your own mooring apparatus and your boat comes off, for whatever reason, and creates damage to another boat or property, how does your insurance company view this??
There may be a lot of opinions regarding this issue and I know that construction of mooring apparatus and the qualifications of mooring inspectors is a dogs breakfast here in NSW, but has anyone asked their insurance company how they would view a claim for damage resulting from a amateur built mooring failure???
If what Ramona says is correct, then doesn't that make an even greater joke of the whole mooring issue. Surely there would be some review of your qualifications and or experience. Shoe salesman today, mooring contractor tomorrow. You've got to do a course to be a Stop & Go (Traffic Solutions Engineer) person these days so why wouldn't you have to have some sort of qualification for moorings. What about insurance companies, wouldnt they want to see some sort of qualification/experience before they either cover mooring contractors, public liability ect or pay out for damage to a boat or property caused by a failed mooring?
Mike
As to the batteries issue - galvanising should not be an issue. All my moorings have had gal on swivels and thimbles. The anode is the metal that will lose electrons and degrade. The job of galvanising is to plate the steel so that you get physical protection and then when there are cracks or fissures in the zinc, you get cathodic protection.
So having some parts galvanised will protect all of the steel that is connected to the zinc galvanising. That is how zincs protect propellers and motors. The zinc will lose electrons and degrade, which is what we want to do. Being part of a galvanic cell, is fine if the part you want to keep is the cathode. So use gal swivels and the zinc coating will protect the black steel chain too, but it will make the gal wear away quicker when connected to another cathode.
cheers
Phil
