Cruising Anchor Chain Length

[dadster3]

The really serious cruisers I have talked to--and by serious I mean those who cruise full time, many of whom make their living writing, teaching or consulting about cruising--I don't think I have met a single one that carries less than 300 ft. of G4, usually 3/8" or 1/2". If you are a local weekender or occasional sailor, that's probably overkill. It's a lot of weight--300 ft of 3/8 weighs over 600 lbs.--but that extra weight adds to the holding power at anchor. It keeps the chain on the sea floor and the pull on your anchor more horizontal.

[s/v Jedi]

I see the discussion moving to the weight of the chain being important. Don’t go there before you are sure your anchor is big enough because anchor weight and size trumps everything. I read about 40’+ boats with 25kg anchors announcing that being good... no, you need to aim for double and when that doesn’t fit on the roller, compromise to one size down.

“Holding just fine in 50kts” with an undersized anchor: sure, in perfect seabed conditions. How does it do in grass? In hard bottoms? The anchor size needs to be right for the worst conditions, not the best.
Of course, in this case the poster comments they sail the BVI, which means his choice is correct. This thread and thus my recommendations are for blue water world cruisers that go everywhere.

When that is done, look at the chain. Here, strength and length are key, not weight/size. If you carry 200’ 1/2” BBB, you can go for 400’ 5/16” G7 and win (I’m guessing,didn’t do the math). Take 400’ and only compromise down towards 300’ when you really can’t fit 400’ of G7 that is strong enough

[Rimica]

Just spent 2 years in the Med including being at anchor during the Medican 2 years ago in 50 knots of wind


We have 50 meters of 10mm chain and 125 meters of rode. Seldom de we go past the chain. I found that 50 was just fine.

[01kiwijohn]

I use 150ft of 5/16 inch hi test spliced to 250 ft of three strand 5/8 inch nylon. We anchor in depths from around 20 ft to 60 ft, max between 70 & 80 in Alaska.
boat displaces 14000 lbs. if I have doubts, I often use a trip line, so I can pull it out backwards if trapped in debris on the bottom. If an abrasion issue, I tie a fender onto the chain end to keep the rope off the bottom.
I anchor between 85 to 120 nights a year and have, so far, always wake up in the same place as I anchored.

[sailoray531]

Good point about the shock lessening affect of rope rode. I have 100 feet of chain attached to 150 of rope rode. I like the combination for weight and shock absorption. There are downsides, however--ensuring the integrity of the chain/rope connection and the crossover at the windlass between chain and rope.

[Yellow bird]

Originally Posted by s/v Jedi

For linking chain you can get these. They maintain link spacing and are as strong as the chain (G7 marking is visible) but they are not galvanized. I spray them with zinc every time we’re doing maintenance on the anchoring system

Does it works without problems on gipsy?
If yes it's realy great!

[Paul Howard]

I have cruised a total of 15 combined years, a trade winds circumnavigation of the world, plus high latitudes north and south of the equator on 200 feet of all chain rode.
I have occasionally (probably less than ten times) added another 100feet of rope to the chain in very deep anchorages, such as at Pitcairn Island and some of the Pacific Atolls and in the Falkland Islands.
I have also sometimes put out more than one anchor, never more than three at a time, but this was because of changing wind direction, not depth. Anchoring in up to 100knots of wind has not been a problem.
Chain is heavy and bulky if wanting it to self-store and expensive and needs occasional end-for-ending.

[s/v Jedi]

Here it is at Grainger but I have even seen it at Tractor Supply. These are easily available and there are others as well. Peerless seems to have one that looks like it’ll work.

The one I have does pass the Gypsy without trouble but I did manage to have it jump off when hauling in a slack chain. When I go easy as it passes it works 100% of the time.

https://www.grainger.com/product/9XH...UaAgKREALw_wcB

[FranklinGray]

Originally Posted by Dockhead

However, I think every single realistic cruising boat combination of chain will be bar tight in 35 knots. It might have taken longer to get there for a lighter boat with a heavier chain, but by 35 knots virtually every boat has gotten to a bar tight chain.

First off, chain never gets bar tight. That is impossible. It may be close to straight, but never straight.

Example of my boat in 40 knots of wind:

With 70 of chain out, there will be .5 feet of sag. With 200 feet of chain out, there will be 4 feet of sag. That is a big difference. Weight makes a lot of difference. That is the reason my anchor will hold in 35 knots of wind with just 3:1 scope in deep water...my chain has a lot more weight on it so the pull direction is not so bad.

And just for your understanding, my boat will produce 1,800 lbf at 40 knots (40x40 x.00256 x (55x6 (freeboard) + (mast and rigging 30)) x 1.2 (Drag) This is calculated to show the worst, when the boat is exposing roughly 40% of it's hull to the wind.


https://www.spaceagecontrol.com/calc...tton=Calculate

[nofacey]

All chain per OP question........80m will get you around the world, but adding 40m of rope will let you stay securely in a few of the deeper anchorages (good to 70ft) you will encounter.

[FranklinGray]

Yes, 70 is common in SP but some anchorages are 100+ they have moorings in the deeper ones so you do not have to plan for that.

As for my previous post, I got the drag wrong....drag is .5, so adjusted for that, my chain will sag 1.2 with 70ft of chain in 40 knots and 10 ft with 200 ft of chain out. On a 40ft boat with 3/8 chain: it is 1.7 vs 15 ft. Of sag. The weight does matter a lot.

[navman]

The best article I've read on the subject is

Catenary & Scope In Anchor Rode

Our yacht is 38', full draft yawl with lots of windage. Our primary anchor is 60lbs with 25M of chain and 100M of brait rode.

I anchor in anywhere from 15-80 feet of water in varying conditions in the PNW. Peter's article has served us well.

Similar reasoning was applied to earlier days cruising in the Caribbean and Bahamas.

I have never had any need or desire for more chain.

My deck hardware suffers less, and overall, the performance at anchor has exceeded my expectations with the mass focused on the anchor, and less on the rode.

Side benefit is we're not schlepping tons of dead weight around in the forepeak, which would contribute negatively to pitching moment and sailing performance in heavy conditions.

[bobnlesley]

Originally Posted by CAVOK

Is there any consensus about what is the ideal anchor chain length to carry on a cruising yacht. We intend to cruise the Med then over to the Caribbean and possibly further...an opinion based on experience.

With 50m sailing in the Med, Atlantic and Caribbean we never once felt 'I wish we'd got a bit more', but if by 'possibly further' you mean the Pacific, well we're there now with 70m and on just couple of occasions I've wished that we had just a bit more; just so that we could've got a full seventy into the water, with enough left to reach back to the windlass. The reality is that those few metres would've probably been irrelevant, but I'd have had more peace of mind.

[evm1024]

Anchors and chain of my!

Bar tight does not mean straight as a rod. No, wait! Have you ever seen what a 70' rod looks like if you pick it up at each end? Not straight!

For our working discussion can er agree that bar tight means that when you apply a transient force of X on one end of the chain that you get near X force on the other end. i.e. the chain did not act as a shock absorber.

And lets talk sag.

With 100' of chain at 1# per foot of chain weight and 500# of force through the chain the sag will be about 2.5'

Kick the force up to 1000# and the sag will be about 1.25'

For 2000# force the sag will be about 0.625'

and for 5000# the sag will be about 0.25'

for 10,000# the sag will be about 0.125'

And lastly for 25,000# the sag will be 0.025'.

The argument that has been given is that the sag never goes away.

My question is: When did your anchor pullout or chain/shackles break or deck hardpoints break?

and lastly, lastly the key point of the "last link lifting" off the seabed is the change of direction of pull on the anchor. Things can go to heck quickly.

[navman]

Originally Posted by evm1024

My question is: When did your anchor pullout or chain/shackles break or deck hardpoints break?

I sat out Hanna in 2008 in the Bahamas at Anchor, and the deck hardware (very robust installation on an S&S yacht) took a beating, and I had lines led aft to the primaries from the deck cleats.

In the gusts we would surge aft noticably, and I am thankful that chain made up only a small percentage of the overall combination which began with a 90lb anchor, which held without dragging. It was so well set after the storm I had to dive on it to dig it out.

Had I used all chain I am confident some of the stronger gusts would have produced peak loading on the deck hardware that would have either damaged it, or damaged the deck. As you know, S&S yachts are not built by yards that skimp on build quality, and Rod was maniacal about engineering the related structures.