Chain length

[CSY Man]

with an 88lbs Rocna.

How do ya like that Rocna...?

[schoonerdog]

This article explains the dynamics of textile/kellet, textile/chain/kellet and chain only. Rode Static Behavior 2. And no, monohulls, I didn't mean to exclude you! We simply would all agree that multihulls have less load carrying capability, are safer and more manueverable when light, and therefore need to keep their chains at smaller lengths than would a monohull of equal size. I was trying to find out in practice what most multihulls were doing. I think that the rode/kellet system which chain and nylon rode would be equally effective and perhaps even superior to all chain in everything except for a deep anchorages above sharp coral which has large tidal shifts because at low tide the rode might drift to the bottom and become enwrapped over the coral heads and cut free. I also think that all chain might be logistically easier for weighing anchor on sandy bottoms but not for mud.

[schoonerdog]

there is a technique for anchoring which I haven't tried but also seems effective with chain. Putting out more chain increases your swing radius and thats not always wanted. Putting out a kellet would help keep your chain parallel to the bottom without increasing the swing radius, but its another heavy thing to lug around. I'd seen somewhere putting down the amount of chain you want for say a 5 to 1 rode, and then putting down more chain looped together to work as a kellet. Not sure what that is called or how it's done, anyone know?

[West Coast Cat]

On our Catana 39S we have 250' 3/8" for our primary, a 45lb CQR, we have a danforth 55lb with 100' 3/8" and 200' rope, and a third anchor with 60' 3/8" chain and 220' rope.

[cat man do]

Originally Posted by schoonerdog

We simply would all agree that multihulls have less load carrying capability, are safer and more manueverable when light, .

Bloody Hell, don't let the Lagoon owners hear you talk like this.

Dave

[swarren]

200' all chain primary for me. I like on my cat that the anchor chain is stored pretty much directly beneath the mast.

[SkiprJohn]

So why are multihulls anchoring differently than monohulls? This is a serious question. I teach sailing on a multi and on several monohulls and use the same formula for all except I tell everyone to drop the sails at anchor on the multi in any kind of weather and condition whereas we can keep the main up and luffing short term on monos.
Did I stick my "bow" in where it doesn't belong?
Kind Regards,
JohnL

[craigsmith]

Originally Posted by SkiprJohn

So why are multihulls anchoring differently than monohulls? This is a serious question.

Because they tend to be more sensitive to weight (read: chain) and can also typically anchor in shallower water.

------------------


I'll take the opportunity to post a link to one of my recent articles:
Chain, Rope, and Catenary - Anchor Systems For Small Boats

[Keegan]

Originally Posted by maxingout

I am a Privilege 39 catamaran, and I used 200 feet of 3/8 inch high test chain during an eleven year circumnavigation. We regalvanized the chain twice - once in New Zealand and once in Australia. If I do another circumnavigation, I will use the same chain, but regalvanize it again before I set sail.

In your eleven year voyage how many times did you feel the need to add nylon rode to the end of your 200' of chain? Was 200' truly enough?

Keegan

[Keegan]

Originally Posted by craigsmith

Because they tend to be more sensitive to weight (read: chain) and can also typically anchor in shallower water.

I'll take the opportunity to post a link to one of my recent articles:
Chain, Rope, and Catenary - Anchor Systems For Small Boats

Craig:

I read your article with interest. Your canadian distributor shipped my Rocna 33 out on Friday and I cannot wait to give it a try. I now need to make a final decision on Chain. My Dolphin 460 Catamaran will come in fully loaded at about 29,000 lbs. and I currently have 8mm chain (probably chinese chain) that was on the boat from the manufacturer. After reading several articles including yours, Dashews and others I am considering either G7 5/16th chain from ACCO for wait savings, or 3/8" HT ACCO, for strength over weight savings. I would prefer to go with the G7 5/16 High test but I am not completely confident that this is enough strenghth in a BIG blow. I would be using a nice long stretchy bridle up to 30' so this should give me plenty of shock loading protection if I choose the smaller size chain.

If I take your article at face value, it would be, but there are always multiple arguments to consider. I also found G7 chain out of Italy in metric sizes from Maggi and that fits my Gypsy that I currently have.

The other hassle with G7 ACCO is that it will not fit my European Gypsy-Goiot. I believe the only manufacturer that makes a gypsy for the G7 5/16 is Maxwell

I am starting to believe that 200' is enough chain, of whatever size chain I end up with and then I would have some additional rode with a long bridle and shackel attachement for additional lenght in severe conditions.

Anyway, what are yours and others thoughts on this set up?


Keegan

[craigsmith]

Keegan, thanks for the comments.

I would say either the 5/16th G7 or Maggi G70 metric equivalent (8mm?) would be ideal. I assume either would mean changing your gypsy, as if it was sized for lower strength chain it's probably 10mm? You do not say.

On the strength issue, do try to compare breaking strains rather than SWLs, as the hi-test will not be comparable to others.

As to length, I should say that 200' is probably more than enough for any cat, but of course it depends on typical depths where you intend cruising. (E.g. up to ~35' depth [assuming ~5' height to roller] you'll be able to manage at least 5:1 without the chain ever leaving the wildcat.) I would say it's probably quite conservative.

[Roy M]

Previously I had 300' of 3/4" braided nylon with 100' of 5/16 BBB chain, on each of two rodes, plus a backup of 50' of chain on my 12H Danforth "emergency brake". After installing a Lewmar electric windlass, I have converted to 300' of 1/4" High test chain for the primary, and kept the 300' rodes as backups, with1/4" high test.

Not wanting all that weight forward when it wasn't needed, I built a trough from the forward chain locker, aft to just forward of the centerboard trunk. I've got a couple of rollers (used on trailers) to guide the chain when it needs to roll out in a hurry from the aft storage location. Normally, I carry just 100' in the bow anchor locker ( about a hundred pounds of load) which doesn't seriously affect our bow bouyancy. Incidentally, the terminal end of my chain is attached to 100' of 1/2" yellow polypropylene line, which is then attached to some light nylon cord. If I ever have to "cut and run", it's easy to let everything go out, slice the light line, and recover the chain later which is waving its yellow flag on the surface. The 1/2" line passes through the Lewmar as well as the chain, making recovery pretty simple, and since the chain is resting atop it in the after chain locker, it doesn't scrape up the bilge while underway.

[GordMay]

Roy:
I presume that you have to stow the rode (near midship) by hand.
Does it require an assistant to drag the chain back, as it is raised aboard - or can you dump it into the bow locker, then drag it back afterwards?

[Sandero]

I am curious as to the weight of your boat Roy and how the performance changed by moving the weight of the chain aft. I know that this makes a theoreticalk difference to have the weight mostly down and at midships, but practically what have you noticed?

Was your bow trimmed lower with the weight forward? My own experience with weight distribution on a 16k# vessel is that the trim was not affected much by moving some chain aft. When cruising the entire water line dropped a few inches from the weight of stores and gear.

I helped in a delivery and the owner decided to remove the heaving anchor and chain and place them over the keel. Fine and dandy before departing. But arriving it was a bit difficult getting all this set up "underway" and luckily we were able to pull along side a dock on arrival and set up the anchor gear.

Since many cruising boat are carrying a lot of tackle at the bow, I wonder what the downside for them is. Any comments?

jef
sv shiva

[Roy M]

First, reponding to GordMay: When I was designing the new installation for the windlass, I knew that I wanted several things that I hadn't seen on other boats. One, I installed up/down buttons in a custom box attached to the pulpit. I'll try to send a picture later. It looks like a robot head, so I called it C-3PO. In the box is a socket for a QUICK remote windlass control and chain counter. While I was doing the wiring, I added additional sockets in a variety of places, allowing me to operate the windlass from the cockpit, the aft deck (when using the capstan to haul the dinghy aboard), in the chain locker at the bow, and one more in the aft bilge locker. So, assuming I've withdrawn some chain from the 200' normally living aft, I can simply plug in the remote in that bilge, push the button while pulling the slack chain aft through the trough, and read on the chain counter when I've got enough aboard, then go forward to the main locker to make sure everything is falling smoothly into place, plug in the remote and continue pulling chain until I get to the muddy parts. Then I go on deck, grab the high pressure saltwater washdown hose, and clean the chain before it goes into the bilge. It works well and I'm pleased. As a sidenote, the boxes that hold the remote sockets also have up/down switches AND a bright red LED to remind me the power to the windlass is on, and to help see the process in the dark. I try to make stuff work easier for singlehanding or with new crew. The LED on the pulpit box is aimed at the windlass, giving it the appearance of a red nose to the robot head, and lights up the foredeck at night. I put it on the pulpit because I hated stepping on the deck buttons on other boats, only to discover that the power hadn't been shut off. People can get hurt badly with that arrangement.

To Defjef: My boat weighs about 12,000 lbs loaded, so 300 pounds of chain in the forepeak would make a lot of difference in its balance and performance. Therefore, most of it goes aft where it sits for its time of need, leaving enough chain to anchor in about 30 feet of water most of the time.