What is Too Much Rode?

[a64pilot]

I’m sitting in 25 kts of wind, anchored in mud. I did set the anchor, but only backed down at 1500 RPM, cause it’s mud.
25,000 lb boat, 40 kg Rocna, eight feet of water.
Initially put out about 50 ft of chain, started to drag after an hour or so, out out another 25, I think I still drug, so put out out another 25’.
Total 100’ of chain in eight ft of water, seems excessive, but want to stop the drag.
Brings up the question though, I’m sure there is a point of dimensioning returns, but at what scope does it become counter productive or does it? Meaning is there a point that more equals less holding?

[Stu Jackson]

Anchor Scope Illustrated Photo Gallery by Compass Marine How To at pbase.com

[Benz]

More rode can only equal better holding, since it'll be more weight below (assuming you're on chain), but other factors have to be considered: swinging room, nearness of neighbors, the possible need to pull it all up and reset. If 100 feet in 8 can't hold you, perhaps another anchor off the bow to form a V. I've done this often in high winds with marginal holding. My second anchor is a Guardian.

[Suijin]

No, there's never a point where it means less holding, at least from the perspective of scope and weight.

I've had circumstances where I have dumped 200' of chain out in less than 12' of water with a storm coming and no other boats around and slept well.

I'm also suspect about your boat being only 25,000. Have you weighed it in the slings fully loaded, water and fuel? My boat has a "factory" weight of 22,000. Coming out of the shed after part of my refit a month or so ago, no mast, most stuff off the boat, water tanks mostly empty, she tipped the scales at 26,000. You have a ton of stuff on you boat and I would not be surprised if you're north of 30,000. Of course that horse of an anchor should be fine even if it is, but just sayin'...

[sailorboy1]

8 feet of water plus 1.5 foot tide plus 4 feet to bow equals 13.5’

100’ of rode isn’t all that all that much for bad conditions (25 winds with only 1-2 foot chop aren’t really bad conditions)

The only rode that is counterproductive is the rode in the anchor locker. In the many gales I rode out last year it seemed after 12:1 it didn’t anything better, but 10:1 was a lot more comfortable than 7:1

[sailful]

More rode will never mean less holding. If you have the room I would put out all the chain you have. Each link in the mud adds friction, helps keep you in place.

[SVRapture40]

wow! 40kg Rocna with 100' of rode (chain I hope) in 8' of water on a mud bottom and that won't hold a 25,000lb vessel in 25 knots of wind? I can tell you right now, your anchor is NOT set. Pull it up and try again.

My Rocna 40 has held my 25,000lb vessel in more wind than that with less scope than that and never budged.

I am just saying - something is wrong.

[a64pilot]

I have one other boat in the anchorage with me, and I anchored about 100 yards from him. He is ahead of me, so I can not drag into him, and there will be no wind shift for 24 hours.
I am all chain.
I have seen Maine Sails dissertation, I think I have read almost all of his knowledge base, only things I have not read don’t apply to me cause I don’t have that engine etc.

I know that at about 7 to 1 there is a point of diminishing returns, but is there a point to where your actually hurting by putting out more?

Letting out that last 25 seems to have stopped the dragging, but maybe the first 25 did, the second was I guess cause I’m paranoid.

[a64pilot]

Originally Posted by SVRapture40

wow! 40kg Rocna with 100' of rode (chain I hope) in 8' of water on a mud bottom and that won't hold a 25,000lb vessel in 25 knots of wind? I can tell you right now, your anchor is NOT set. Pull it up and try again.

My Rocna 40 has held my 25,000lb vessel in more wind than that with less scope than that and never budged.

I am just saying - something is wrong.

Yes, it has held me in more wind also, and with shorter scope.
Actually my 25 Kg Rocna did, I bought the 40 for really bad weather, then decided, you have it, way not use it?

Got me wondering if I should go back to the 25 ?

[boom23]

Maybe your anchor is fouled? It might worth it to pull it up and reset it, especially if there is bad weather coming.

My Manson Supreme dragged in mud also and I had plenty of chain only scope. It held when I reset it.

[Mike OReilly]

I don’t see how it could ever become counter-productive A64, assuming you’re ignoring all other considerations of shoreline, neighbours, or the challenging of hauling up. But obviously it’s not a linear relationship between pull angle and rode length. The benefits of adding another factor asymptotically approaches zero. After 7:1 the benefits become small. I’ve only purposely gone beyond 9:1 when I’m preparing for a serious blow (like an approaching tornado, or a hurricane-force front).

I don’t think there’s any surprise that 50’ wasn’t enough. You say 8’ water, but how high is your bow? Typically another 5’ off the water, so now we’re at 13’. I’d probably round that to 15’ for my calculations (No tide?).

My minimum sleeping-comfortably scope is 5:1, so right away you’re looking at 75’ to begin with. With winds above 20 knots I’d definitely want 7:1, or more if I can, so 105’. Your 100’ sounds about right in my books. But if I can, I always put out more.

Why not back down on it hard? If it will drag when you back down, then it will drag in high winds. If it drags at full cruising RPMs (which is 1800 for me), then I put out more scope, or try a new set, or on rare occasion, accept the situation and keep constant eye on things.

… actually, I wonder if a 40 kg anchor could be too much for your boat. This is me just musing out loud, but that’s got to be at least two sizes bigger than suggested. And Rocnas are already supposedly over-sized to begin with. I carry a 25 kg Rocna for my 30,000# boat, which is actually slightly larger than suggested. I have never dragged once properly set.

Could it be that you’re not able to get a sufficient set with such a large anchor? I honestly don’t know...

[thomm225]

I don't worry about it and just put out tons of scope especially if no boats are around. I had the 40' of chain out here and at least 75' of 5/8 rode before the 40 knot winds hit and I didn't drag at all. Water was about 8' deep also.

https://www.youtube.com/watch?v=zHt7ocBZKms

https://www.youtube.com/watch?v=okRZs6os5Eo

[a64pilot]

Neighbor is dragging too, he is now almost even with me, meaning he has drug a long ways, he was at least 25 yards ahead of me, before I let out the extra chain.
Wind is slowing down though.
It’s more of a learning experience for me now, 99% of my anchoring has always been in clean sand anchor hooks, and I mean sets suddenly and hard.
However in mud it seems to need to soak awhile, I can pull it considerable distance if I pull hard when it’s first dropped, but give it time and it sinks in I guess.
I’ve never had it drag before, but this is the second time this trip, first time was the other day, I let out more chain and it stopped to, but I had a heck of a time raising it, it came up with honestly a three thick steel cable on it, was fun getting the cable off. Cable I’m sure stopped the drag then.
Look at how hard the bend is on the anchor, it was really buried I guess.

[thinwater]

Originally Posted by a64pilot

I’m sitting in 25 kts of wind, anchored in mud. I did set the anchor, but only backed down at 1500 RPM, cause it’s mud.
25,000 lb boat, 40 kg Rocna, eight feet of water.
Initially put out about 50 ft of chain, started to drag after an hour or so, out out another 25, I think I still drug, so put out out another 25’.
Total 100’ of chain in eight ft of water, seems excessive, but want to stop the drag.
Brings up the question though, I’m sure there is a point of dimensioning returns, but at what scope does it become counter productive or does it? Meaning is there a point that more equals less holding?

In 8 feet catenary is not very effective. 50' is only 50/(8+3)=4.5 scope, which is ludicrously short for the conditions. 75 feet is still only 7:1, not a lot for very soft mud.

Do you have a snubber at least 20 feet long to reduce shock loading? that would probably reduce the load nearly 50%.

I don't know how you set the anchor. However, unless there is a good reason not to, the best thing to do is to start over from the beginning. As others have said, it is likely you have caught some rubbish on the hook by now. This time, put down 100 feet of chain, attaching a snubber at the 75' mark. The snubber should be no more than 1/2-inch for your boat and could be a long dock line. You can attach it to the rope by cow hitching the eye to the chain.

East Coast mud can be really soft. We don't know what you've got. In independent testing, I've seen a 45-pound Rocna hold as little as 400 pounds, which is marginal in 25 knots unless you use a LOT of scope and a snubber.

Actually, in soft mud there is good soil science that shows that waiting 2-4 hours before backing down can yield much better holding. This give the mud time to consolidate around the anchor, helping it set deeper, where the mud is more firm. Unless the anchor gets deep, it won't hold much. This is why in soft mud you want to use a LOT of scope during the delicate consolidation period. You want the anchor to sit as quietly as possible.

[captstu]

I used a tandem anchor setup when expecting weather. The Manson is on all chain with 8’ of chain shackled to the trip point and a Fortress further from the Boat.

One bad storm, Wilma, I had 200’ of chain in 12’ of water. Chain hooked Boat with 2 bridles, both 5/8”.

The eye went over the boat causing her to run down the chain, over the anchor and fetched up on the other wind direction. The Boat lurched to a stop, broke both bridles and stretched the chain into uselessness.

The Boat held and the Fortress bent into uselessness and was replaced under warranty.

I have always wondered if a shorter rode would have kept the boat from getting up to speed.

I did learn to always turn your rudder far over and rope the wheel. This would have minimized my boats damage. All the boats with one or two spread anchors ended up stacked on the beach.