Anchor chain. Change from 8mm to 10mm ?

sarabande

sarabande

Well-Known Member
Joined
6 May 2005
Messages
36,182
Visit site
32ft Sailing boat, 6 tons displacement. Two main anchors (sized for a 36ft boat) both currently on 8mm chain.

I am lusting gently for a manual winch to ease the workload on a creaky back.

I've had a very useful progressive talk with SLSpares, the Simpson Lawrence winch man. He recommends the Seatiger, for which the smallest gypsy is 10mm., and by chance I have 60mm *** of calibrated good chain from my 36ft previous boat. :)


Question. Is 10 mm chain an excessively oversize upgrade choice, in order to accommodate the Seatiger winch ? I have a very conservative approach to equipment, and am happy with the idea lying to weightier chain matched to the (relatively) large anchors. Am I being over-cautious ? A third anchor (kedge) is on 8mm and will remain at that size.


*** EDIT. That is Exmoor speak for 60metres O:
 
Last edited:
On a windy night no-one wishes that they had lighter ground tackle.

I was taught to be cautious (there's a thread about that elsewhere...) and thicker chain and heavier anchors with an electric winch vs. lighter anchor, chain and no winch seems to be a no brainer decision. Do the upgrade and sleep well at night.
 
The only downside I can think of is that the extra weight of the chain and windlass might upset the trim of the boat.
I have an SL Anchorman winch with an 8mm Gypsy, have you researched thoroughly?
 
sarabande said:
32ft Sailing boat, 6 tons displacement. Two main anchors (sized for a 36ft boat) both currently on 8mm chain.

I am lusting gently for a manual winch to ease the workload on a creaky back.

Question. Is 10 mm chain an excessively oversize upgrade choice, in order to accommodate the Seatiger winch ? I have a very conservative approach to equipment, and am happy with the idea lying to weightier chain matched to the (relatively) large anchors. Am I being over-cautious ? A third anchor (kedge) is on 8mm and will remain at that size.
Click to expand...

G40 8mm will have a breaking strength of something like 12,000lbs (5,500kg), so you cld probably swing your boat off that! 10mm is therefore prob a bit excessive, notwithstanding your sensible desire to be on the safe side.

Then again it would have its advantages: retrieve say 100m of 10mm and you shld be able to give your prop a quick polish ;)
 
sarabande said:
32ft Sailing boat, 6 tons displacement. Two main anchors (sized for a 36ft boat) both currently on 8mm chain.

I am lusting gently for a manual winch to ease the workload on a creaky back.

I've had a very useful progressive talk with SLSpares, the Simpson Lawrence winch man. He recommends the Seatiger, for which the smallest gypsy is 10mm., and by chance I have 60mm of calibrated good chain from my 36ft previous boat. :)


Question. Is 10 mm chain an excessively oversize upgrade choice, in order to accommodate the Seatiger winch ? I have a very conservative approach to equipment, and am happy with the idea lying to weightier chain matched to the (relatively) large anchors. Am I being over-cautious ? A third anchor (kedge) is on 8mm and will remain at that size.
Click to expand...

I think you will have to buy some more chain though 60mm is not really enough to lie to even in calm conditions:p Being serious apart from the possible widget affects on the trim of the boat nothing wrong with the idea although I don't think there is anything wrong with your current ground tackle, there has to be a manual winch suited to 3/8ths chain somewhere.
 
For our 42 foot boat I will downsize to 8mm from 10mm when I next have to get a new chain.

Advantages - more will fit in the locker - just have 60m plus 60m warp now.

Disadvantages - will have to change the gypsy on the Lofrans Tigres.

But all the evidence says that breaking strain for 8mm is already far more than adequate, it has almost the same amound of chafe protection (any difference practically irrelevant as you would notice severe wear) and the only place where weight matters is the anchor, except in very light conditions when you have nothing to worry about anyway.

The only key thing is to have stretch not catenary as part of the set up as catenary reduces to almost no shock absorbtion in a moderate wind whether 8 or 10mm
 
I have a 12 tonne 35 footer and wished very much that I'd fitted 8mm chain. There is no way that my anchor would hold past the point that the chain snapped! That 10mm chain weighs a huge amount and adds to the pendulum effect of the boat pitching and when we need to manhandle it it's insanely heavy. If I was off to distant shores maybe a different call but i don't see why. 40m of 10mm is a big load up front.
 
Going to 10mm chain is a mistake, especially if you're only thinking about fitting a manual windlass. I'd almost be thinking about looking for high test 6mm chain rather than going up a size as that would ease the handling problems. And I'm also puzzled as to why the OP is looking at a SL windlass when the last one was made some years ago.
Edit
The thread prompted me to look on eBay. There's currently a SL Hy Speed winch with 8mm gypsy here https://www.ebay.co.uk/itm/152266466101 so perhaps that's the solution for the OP.
 
Last edited:
Jonathan Neeves is now using Grade 80 6 mm chain on his 38 ft catamaran and reports no disadvantages but considerable advantages in terms of weight. 10 mm chain is way over the top for a 32 ft boat in my opinion, the weight of it will undoubtedly affect the trim of the boat. And has been said, far stronger than it needs to be. Our boat, 34 ft and around the same displacement has been on 8 mm chain throughout our long ownership, in some big blows, but never showed any signs of being over-stressed.
 
Going to an electric winch will need more resources and time than I can dispose; so a manual one is the route forwards.

I like the idea of a vertical windlass, but my chat with SLSpares leads towards a horizontal two-speed one - the Seatiger. I tend to rely on the knowledge of people who have spent a lifetime doing one thing - in this case, servicing SL winches.

The option of 10mm is because I have it sitting in a bin about 50 yards away. I'd love 8 mm SuperProof Grade120 with each link loving inscribed with the initials of the ten-year time-served metallurgist who fashioned it, but bird in hand, etc.


60m of 10mm chain is 138kg; of 8mm is 86kg. And I have an instinct tuned by years of heaving gert big weights around on tractors, that a heavy chain enables a good anchor to do the job for which is it designed and built - otherwise a length of 6mm dyneema would suffice.****

****6mm, 6m, Exmoor speak again :blushicon:
 
Last edited:
Having used a boat with a manual windlass (SL windlass), 10 mm chain and 60 lb CQR I can tell you that it is back breaking work swinging back and forth to haul the rode at any reasonable rate.

I would strongly suggest that smaller diameter chain and an electric windlass is what you need if there are any back risks. In the case I make above we had a crew which manually hauled the anchor. On the few occasions we had no crew on board it was an awful experience using the winch. I have also hauled up my own 10 mm / 60 lb CQR by hand by squatting and using my legs, by sitting and rocking back - all equally limiting. I think you should seriously consider budgeting for an electric windlass.
 
vyv_cox said:
Jonathan Neeves is now using Grade 80 6 mm chain on his 38 ft catamaran and reports no disadvantages but considerable advantages in terms of weight. 10 mm chain is way over the top for a 32 ft boat in my opinion, the weight of it will undoubtedly affect the trim of the boat. And has been said, far stronger than it needs to be. Our boat, 34 ft and around the same displacement has been on 8 mm chain throughout our long ownership, in some big blows, but never showed any signs of being over-stressed.
Click to expand...

Agreed - total overkill.
If you can afford the weight up front, much better IMHO to have extra chain length than heavier chain.
Ideally any anchor tackle you have should be manually retrievable - probably not feasible for a 60' boat, but easy enough on a normal size boat.
 
ok, now I'm intrigued. Can anyone answer: what is the point of chain?
If the wind is strong enough to drag an anchor, then the chain will be bar taut with negligible catenary and have no useful stretch. I get that it has good abrasion properties, but probably that could be achieved other ways.
Jeremy
 
scrambledegg said:
ok, now I'm intrigued. Can anyone answer: what is the point of chain?
If the wind is strong enough to drag an anchor, then the chain will be bar taut with negligible catenary and have no useful stretch. I get that it has good abrasion properties, but probably that could be achieved other ways.
Jeremy
Click to expand...

It's chafe proof and I'm not sure what other line would have those properties
 
Interesting thread here! There is a standard ship test which requires the chain to be deployed in deep water so that the whole lot is suspended from the windlass.Next the tackle is required to be hauled back up again,either by windlass or electrically powered windlass.
I would avoid going to 10mm diameter chain for this reason,that it might be impossible to recover the Anchor,and also the weigh of any decent length of 10mm chain is colossal in terms of the trim (OP's commented) .
I have had the chain jump off the gypsy(10mm) deploying all automatically,the windlass gave up on recovery,and I had to ask assistance from another substantial yacht who kindly used their hydraulic windlass to recover my gear.So I for one will be downsizing to 6/8mm to carry more length in a recoverable fashion.I now have two more house batteries as well so it is surmised that the Lofrans Cayman 1200 watt will be happier with a beefed up supply!
 
We have just scrapped a knackered Goiot horizontal manual windlass with 10mm chain in favour of a new Lewmar horizontal electric windlass with 8mm chain (largest gypsy size available) on a 36' 6.5 tonne boat. Both chains are 30m, with 30m rope, and the anchor is a 15kg CQR. Apart from the cost of the new windlass, which I installed myself, I have absolutely no regrets. At age 65 I was finding cranking the old windlass a serious pain in the back, and the prospect of having to do so was beginning to inhibit us from anchoring at all.

If the budget won't run to electrics, future proofing your sailing would suggest using lighter chain.
 
Snicker....

I have a 34' catamaran (similar to 40' mono) and have been happy with 6mm G43 for 20 years (the chain has been replaced, of course). On a 34' mono, with any decent snubber, the working load in a storm will be perhaps 800 pounds, or about 5% of BS. 6mm G43, by comparison, would be at 11% BS and 30% WLL. My peak storm load is closer to 50% WLL (17% BS), which I am still comfortable with. Neeves has a larger cat, hence the G70. Our snubbers are equivalent, sized for the boats.

anchor+chain.jpg

I do use a snubber to keep the impact force low.

Yes, 10mm is silly, the boat will trim bow down, and the weight would be much better used in an anchor.

And if the guy can't find an 8mm windlass, he's not actually trying... at all.
 
Last edited:
You must log in or register to reply here.

Share this page

Top