questions about anchor chain

[Orion Jim]

Originally Posted by waterman46

I have a bunch of old nails and other hardware in my garage that I really don't want, why don't I just dump it on the freeway some night and let someone else run over it?
Doesn't everyone have puncture proof tires?

Naive and inconsiderate thinking. After having to dive on my boat after snagging your floating hazard, I should be real happy to try to cut through a big mess of line (oh, its only 1/4 inch, so no big deal).

I don't have a rope cutter on my prop shaft. I don't intend to burden my boat with such an item, because most people are considerate enough to not leave lengths of floating line around. But if I did, and I ran over your line, and the rope cutter actually worked as advertised, I don't know if the locals would appreciate a few hundred short pieces of orange rope fouling up their harbor.
Anyway an old fender would be a more visible marker than floating line.

You hit the nail on the head.....

[Pete7]

Originally Posted by waterman46

You need to have a plan to pull up the anchor by hand w/o a working windlass. Carry two chain hooks. Hook to chain at the bow, attach line leading aft to winch. After winching in that length of chain, use second hook at bow to hold chain while you run the first hook back to bow for the next haul.

On a 30ft yacht with say 10 - 15kg anchor and 8mm (5/16th) chain most of us won't have a problem hauling it up by hand, good exercise actually. For occasions when it blowing hard or there is a current running, then yes motor up to the anchor.

[seacap]

Between working as a professional charter captain and my own boat in the Caribbean for the last 30 years I will say this about that 😉 . My setup has always been 60-100 chain and 200’ rode.
I have never suffered chafe on my rode. If you go in the water and watch the action of your chain/rode any breeze at all lifts the chain/rode off the bottom so there is nothing to chafe. Plus you should not be anchoring on reefs or near coral heads anyway. After 30 years in the Caribbean I have never found a need to.

The added bonus is the rode acts as an excellent shock absorber and takes up to 50% of the load off your anchor. Your mileage may very. Making your anchoring more secure.


I prefer the 60/200 setup at this point. My average depth for anchoring in the Caribbean has been around 15/17’ plus 3’ for the bow. So with a total of 100’ out giving me 5-1 scope I have 40’ of rode to absorb loads. And I always put out a minimum of 85’ so I have 25’ of rode in the system. The more rode out the greater the shock absorber.
Hope this helps.

[David Mathis]

5/16 chain is approximately .312" and 8mm is about .323" so they're basically the same with only 11/1000" difference. 5/8 is much larger and heavier, far larger than would be needed on a 30' boat, even in a storm.

[stormalong]

Originally Posted by David Mathis

5/16 chain is approximately .312" and 8mm is about .323" so they're basically the same with only 11/1000" difference. 5/8 is much larger and heavier, far larger than would be needed on a 30' boat, even in a storm.

Wire size is only half the story - Link dimensions is the other. The chain has to fit the windlass.

[David Mathis]

Using an anchor design and weight adequate for the conditions allows one to use a reasonable amount of chain (30-100' depending on the depth) with most of the rode being shock absorbent nylon. Perhaps too much is read about ship's anchor systems rather than pleasure boat anchoring systems. The physics of the cantanary can be overly complex and misleading. If you are anchoring in less than 100', more than 50' of chain isn't needed. The stretch of the nylon will be more of a benefit than the weight of the chain.

[Jim Cate]

Plus you should not be anchoring on reefs or near coral heads anyway. After 30 years in the Caribbean I have never found a need to.

Well, you may never have had to anchor near a coral head, but there are plenty of places where t here are low lumps of coral littering a sandy bottom. And in such places it is all too easy to anchor in the clear and as the wind or current varies, drift around so that your rode, lying upon the bottom, fouls one of those lumps. And no, the rope portion of the rode does not always rise above the bottom in drifting conditions.

we've encountered such conditions in varied venues, including the Tuamotous, Vanuatu, New Caledonia and the Solomon Islands.

You will never convince me that all chain is a bad idea for a long range cruiser.
There's more to successful anchoring than formulae, no matter how satisfying they are to the mathematician!

Jim

[chrisr]

i've skimmed this thread to date and cannot see where anyone has mentioned chain grade. this is at least as important as size

i've been boring everyone i meet explaining how we have swapped 10mm G30 chain for 8mm G40 chain. save 50kg (which is considerable in a cat), for stronger chain

to the OP : suggest to consider carefully using a higher grade of smaller dia chain (suitable to yr gypsy of course)

cheers,

[noelex 77]

Originally Posted by chrisr

i've been boring everyone i meet explaining how we have swapped 10mm G30 chain for 8mm G40 chain. save 50kg (which is considerable in a cat), for stronger chain

Grade 40 chain is only a little stronger than grade 30. So 8mm grade 40 will be weaker, not stronger than 10mm grade 30.

Part of the problem is that the working load of grade 40 is quoted as 1/3 of the ultimate breaking load, whereas for grade 30 a more conservative 1/4 ratio is used. This artificially elevates the apparant strength of grade 40. The above applies even if grade 30 chain is genuinely grade 30. In reality, independent testing shows grade 30 chain is often actually made from grade 40, or close to grade 40 material.

The best way to compare the strength of different anchor chains is to compare the break load.

8mm grade 40 break load is usually quoted as 40kN
10mm grade 30 break load is usually quoted as 50kN

[chrisr]

Originally Posted by noelex 77

Grade 40 chain is only a little stronger than grade 30. So 8mm grade 40 will be weaker, not stronger than 10mm grade 30.

Part of the problem is that the working load of grade 40 is quoted as 1/3 of the ultimate breaking load, whereas for grade 30 a more conservative 1/4 ratio is used. This artificially elevates the apparant strength of grade 40. The above applies even if grade 30 chain is genuinely grade 30. In reality, independent testing shows grade 30 chain is often actually made from grade 40, or close to grade 40 material.

The best way to compare the strength of different anchor chains is to compare the break load.

8mm grade 40 break load is usually quoted as 40kN
10mm grade 30 break load is usually quoted as 50kN

the 8mm lofrans G40 chain we hv is rated at 4300kg breaking load. The 10mm L grade (G30) available here ranges 1000kg - 1170kg MWL. assuming a safety factor of 4, this means a BL of 4000 - 4680kg. so if you wish to be pedantic perhaps i should have said 'for chain of about the same strength'.

mea culpa

cheers,

[waterman46]

If you do have to anchor near coral or in rocks, then any part of a rope rode that is deployed longer than depth under the boat plus freeboard, could snag and part.

With all-chain rode, you usually add a long shock-absorbing pennant (is that the right term?) from any point you choose, on the chain to the bow, which has the effect of creating an adjustable chain length plus rope rode. Depending on depth and other factors, a fixed length of chain on the end of the rope may not be optimal.
Then there is the possibility of chafe at the bow roller. We have a good setup there and never noticed any problem, but if it is windy I add chafe guard and start worrying. With chain, I simply don't have to even think about that.