Deep Anchoring Question

[Mantus Anchors]

Originally Posted by Bash

Marvelous Mark, my hypothetical friend, has been recruited to serve as a Marshall boat at the Americas Cup competitions in SF Bay in August. He has been instructed to be prepared to anchor in water as deep as 100' in up to 30 kts of wind.

Marvelous Mark, who is more a racer than a cruiser, has two rodes. His primary has 40' of chain backed up by 200' of nylon, and his secondary has 30' of chain backed up by 150' of nylon. He wants to combine these two rodes to serve for his Americas Cup lunch hook, but he's wondering whether it would be best to attach them nylon-to-nylon, thus reversing the secondary rode, or whether it would be better to attach the secondary's chain to the primary's nylon so that it serves as a kellet.

Marvelous Mark has a lovely electric winch, by the way, a vertical Maxwell.


What says the forum?

I say NYLON TO NYLON all the way, attach the longer piece of chain to the anchor:
Mostly bc its easier to arrange, 30-40 (45-55 lbs) feet of chain will not do much as a kellet. What you need is scope, more scope make it at least 5:1

and make it easy since its just a few days. The piece of chain on deck will prevent chafe..... And IF this friend wants we could supply him with the best anchor one could get
His very own MANTUS

[jeremiason]

If he is running a Marshall Boat, he should stick with combining the two rodes into one long one... chain to line. This will give him the ability to pull the anchor rather quickly, but still allow enough scope. Svendsen's or any other rig shop can splice the line together and you can purchase a chain splice link and combine the chains.

I have anchored out by Alcatraz in about 90 feet of water and off South Beach a couple of times... The bay has good holding and a scope of 3 to 1 should get him through just about anything he will do.

[klem]

The primary concerns seem to be: holding, ease of retrieval, ease of setup. Not knowing exactly how exposed the anchoring location will be, chafe and shock absorption may be factors as well.

From a strictly holding power standpoint, the holding power will be related to the angle of pull on the anchor. Scope is the most effective way of changing the angle of pull, especially in potentially 30+ knot winds where chain is likely to stretch tight. The problem with scope in this much water is that it takes an incredibly long anchor rode and you will have a huge swing circle. With a good anchor 4:1 should be enough scope to prevent dragging in 30 knot winds but it certainly isn't any extra. Any friends willing to contribute another rode? Where the second piece of chain goes will also have some effect on the angle of pull. From this standpoint, putting all of the chain near the anchor will actually give a lower angle of pull than putting some of it in the middle of the rode.

For retrieval, my concerns would be the switchover to chain and the total weight. The switchover is something that your friend should know whether they need to be worried about. From a strictly weight standpoint, putting some of the chain in the middle of the rode is better so that all of it does not need to be lifted at the same time.

From an ease of setup standpoint, attaching things end to end is probably easier.

[bobconnie]

I don't know about useing anything but chain on the anchor end!! All the chain the man has should be hooked to the anchor to help it set well and easy !! should be no problem liftin this amount of chain and anchor with almost any windless!!! From my days In the Bay, I would add some more Nylon myself ! but I won't anchor for lunch without at least 4 to 1 scope LOL and for this job hes gonna need at least 5 to 1 or more!! just my 2 cents

[barnakiel]

Sell the 40' chain and get an even longer piece (say 150' or so). Use this on the main rode.

Keep the secondary rode for your second anchor.

b.

[Bash]

Originally Posted by jeremiason

If he is running a Marshall Boat, he should stick with combining the two rodes into one long one... chain to line. This will give him the ability to pull the anchor rather quickly, but still allow enough scope. Svendsen's or any other rig shop can splice the line together and you can purchase a chain splice link and combine the chains.

I have anchored out by Alcatraz in about 90 feet of water and off South Beach a couple of times... The bay has good holding and a scope of 3 to 1 should get him through just about anything he will do.

I have to agree that 3:1 scope should do the job in this situation, especially with a new-generation anchor, given that the helm will be manned the entire time.

The thought of splicing anchor rode gives me the shivers. Is it just me?

[FrankZ]

Originally Posted by Bash

I have to agree that 3:1 scope should do the job in this situation, especially with a new-generation anchor, given that the helm will be manned the entire time.

The thought of splicing anchor rode gives me the shivers. Is it just me?

A 3 strand end to end splice doesn't look all that hard to do and should be suit just fine. If one was still nervous about it one could stitch through it as well, but I wouldn't think it necessary.

How are the two rodes constructed now? Is there a rope to chain splice or does the nylon have an eye splice and then a shackle?

If the windlass on the boat can't handle the loaned chain concept I would be inclined to splice the nylon end to end and not worry.

[Paul L]

Maybe I'm missing something here, but all this talk about the need for holding seems a bit over engineered. This is just a lunch hook. They will be on the boat with someone at the helm and a working engine. They need a basic, quick setup to be used for a few times over a few days. I'd make use of the gear the boat already had.

[barnakiel]

If this is so then indeed the original set-up is an overkill already and the question non existent.

Apologies for some over-engineering!
barnie

[capngeo]

Long splice in 3 strand is no issue... once had a rode with three of them in my "poor" days. Besides when I was working tugs we would tow TONS with long splices.

Back to the OP.... as an old tug driver, I'd use a deadweight anchor for that application and ZERO scope (think buoy)... now of course even the mightiest sailboat doesn't have the anchor handling winch of a tug, so a trick we used in the offshore grand prix here in Sarasota was to incorporate a BIG mushroom and a BIGGER liftbag attached in 60'. A long air hose was taped to the rode. When the race was over, a SCUBA tank was used to inflate the bag and all 1000# of cast iron came up; we towed it to the sailing squadron beam crane for lifting out of the water to a trailer.

[KnuckleDragger]

Hypothetical Mark should draft one of his hypothetical cruiser friends with decent ground tackle...

[rebel heart]

Originally Posted by xeon_tsd

Sounds like a good time for "Mark" to invest in some more chain. or as Frank said, "rent" some chain from friends for space on deck.

Anyone I trust enough to let borrow $1000 worth of chain, and my chain at that, would be someone who already knows enough to have their own chain. Sort of a catch 22.

[capta]

First & foremost, you must know the bottom where you are going to anchor. The Bay has everything from mud to sanded (by the current) rock that no anchor will hold on. If you've the time, check out the "Bay Model" in Sausalito & ask them what your bottom will be.
Second, there are a lot of shipwrecks in the Bay. Oops, lost the anchor rode....
I'd go for the heaviest anchor & chain the windlass can handle; possibly some one like West Marine or another chandler (or used gear place?) would donate for the duration?
You could get away w/ 3x scope on all chain or an obscene amount of line.

[Jim Cate]

Originally Posted by Paul L

Maybe I'm missing something here, but all this talk about the need for holding seems a bit over engineered. This is just a lunch hook. They will be on the boat with someone at the helm and a working engine. They need a basic, quick setup to be used for a few times over a few days. I'd make use of the gear the boat already had.

Sounds right to me! Put all the chain at the bottom, use as big an anchor as available, put out 3:1 or so and pay attention... not a big deal.

Cheers,

Jim

[Jbaffoh]

Anchor -> chain->chain->nylon->nylon. Duh. Two splices and one chain link. Any noob can do two splices in less than 10 minutes.