Dragging Anchor

Many will chime in. No mention af depth/scope.

I let out more line to maximise scope and start the engine and get a cup of coffee.

My 15,000 lb sailboat would drag its 35lb CQR in soft mud. That was back when I only had 30' of chain and no winldess.

Used a CQR for 2 yrs Calif to Panama. Island San Geronimo off baja kept dragging with the CQR 25-30kts, finally used a danforth and held fine. Sometimes a different anchor will solve the problem. Not always but just another tool to have.

So what was the scope?


Just about everything you mentioned has little relevance to dragging. Here in the PNW anchorages are crowded and 3/1 scope is the norm but, any wind over 20k and you drag.

I sleep real well at 5/1. If there is a storm in the forecast I head for a dock.

OP, 75 feet of chain at 3to1 means you were in 25 depth, at 5to1 you were in 15 feet. All good until the high winds. Then the chain lifts off the bottom, wave action lifts the anchor shank.
IF you had more chain I would have let out another 50-75. If none then yes turn on the engines to assist.
I have never had a CQR, but those that have say it works, and works is all we need.

75 feet of is a lot of chain if you are anchored in 7-8 ft of water. However, it isn't a lot of chain if you are anchored in 20' of water.
As mgreen mentioned, you didn't tell us how deep the water was.

So the first thing I would do when I realized that the wind was coming up suddenly would be to increase the amount of rode that I have out. I have 300' feet of chain so would lay enough out to give me a 7/1 scope. I would also used the full length of my anchor bridle.

The bridle connect to the boat about 4' about the waterline. So if I am anchored in 40' of water, I'm not going to have enough for a 7/1 scope. I often anchor up close to the shore. So even if the depth is shallow enough for good enough scope, I may not have the swing room.

At that point, I am either going to weigh anchor and find a protected spot to hold position with the engine, and if that isn't feasible, then I'll give myself as much scope as I can and sit at anchor with the engine running. Letting the engine take some of the strain off the ride.

Not a pleasant way to spend the night, but much better than grounding or dragging onto another boat.

Look at the anchor testing done by SV Panope-best Ive ever seen. The CQR was the worst (or one of the worst) tested. Once it came loose it wouldn’t reset due to the design/hinge-just dragged along the bottom.
As mentioned above, letting out more scope is the first thing I would do. Given more time, I would put out more snubber line (30 feet) and create a back loop i.e. letting out more chain behind the snubber, creating a loop half the water depth. This loop of chain adds more weight to help hold the chain down at a better angle to the anchor and also acts like a shock absorber to the scope, slowing the pulling force on the anchor as the chain pulls tight. Obviously this technique doesn’t work in shallower waters. A heavier anchor would be my first choice (modern anchor of course).

It’s hard to have a useful discussion about an anchor dragging without discussing the anchor.
CQRs are junk compared to modern anchors, based on my experience with both. Get a modern anchor in the correct size (bigger than you have) and both the holding power and reliability of that holding will improve tremendously.

In those conditions I'd increase scope a bit if I could. And I'd keep watch. But I wouldn't be motoring against the wind or anything as that's within the conditions I assumed when I sized my ground tackle. Our boat is 38 ft and just slightly lighter than yours. Yet our anchor is of a more modern design and also twice the weight.

I’d never tell you what anchor to replace the cqr with, but 35 pounds is light for the boats weight. Lots of things against you here, not enough scope for the situation, light anchor, sudden high winds. Tough to feel safe after that.
Cqr has been around for a long time and used to have a great reputation. I know lots of people still using them. But they must be oversized to be effective.

What was the secondary anchor type?

Slipping the anchor, assuming proper preparations like a buoy secured to the rode on deck are taken and a method to easily let the rode ride free of the vessel, is something seldom mentioned here. We think about that sort of thing on ships in large part I assume because of the slowness of the anchor windlass. Slipping the anchor instantly frees one of other concerns about it like did it set into the chute ok or is it banging against the hull.

Motoring to the anchor has its own set of complications unless you are 100% certain of the anchor rode's location. All-chain rode is less likely to get tangled in the prop(s), but fiber is another mess altogether. In the lashing rain and noise of a storm, are you even sure of the boat's heading - think magnetic compass here, NOT chart plotter. My powerboats flop all over the compass unless a current is helping the winds to keep the boat locked into a narrow range of headings which will not serve to loosen the anchor's hold with side loading if it does manage to grab after a drag starts. But tangle the rode in the running gear and you are DONE.

I have experience in a 40,000-lb boat dragging a 40-lb CQR (all chain 5/16" BBB chain) when an upstream dam let a bunch of water loose in the middle of the night and again with a 40-lb Danforth in daylight. Two FX-37 Fortresses and a 72-lb Rocna primary bower anchor solved that sort of issue on that boat. My current 30-foot, 12,000-lb boat has a 35-lb Supermax attached to all-chain rode as primary.

Now, answering the mail, as we were always taught to do in the Navy when responding to messages:

What did I do in the middle of the night when my anchor dragged (non-storm) and being swept astern toward six other anchored vessels? I had 10-1 scope, and adding more was NOT going to help. With a fast-retrieving windlass I raised anchor (first mate at the bow watching the tend of the chain so I did not overrun) and got underway and stayed underway until I reached our next destination. Deploying a second anchor would have resulted in a tangled mess. In your stormy situation, assuming plenty of scope was already out, I might well have slipped or retrieved the anchor and gotten underway for max maneuverability and control of the situation. In your situation, there may have been other complicating factors you have not mentioned, but getting clear is sort of my go-to if at all possible.

I don't claim to be and anchor expert. I have used a Bruce since 1990. I am currently sporting a 60lbs. Chinese knock off on my 80,000# boat. All I can tell you is it sets quick and I have never dragged. I also, only anchor in protected areas with good forecasts. Meaning, if it says blowing over 20kts, I'm on the dock.

I’ve sat out a lot of storms in my 40 Albin, weight similar to the op. Been in steady 35 to 40 mph fronts, and several T storms with winds estimated at 65 to 70.
I use a 35 lb Danforth with all chain and a single snubber hooked just above the waterline. I’m generally between 7 and 10 to one scope ratio.
If its a T storm I’ll have the radar on and I’ll be in the flybridge with the single diesel running. Once the wind hits I’ll bump it in and out of gear and take the strain off the anchor. T storms only last a short while so no big deal.
If its a strong front I’ll stay in the flybridge a while and monitor but I never dragged using the ground tackle I described. I’ll just let the boat do the anchor dance and as long as the wind is steady I dont get crazy.
If I’m in unfamiliar or poor holding I set a second anchor at some angle and a little less scope. Secondary was a 44 Delta with 20 feet of chain and 3 strand nylon.
That’s what worked for me. And i had a great first mate who knew how to set the hook.
( now we just level the travel trailer and put down the stabilizers).

I don't think he is asking which anchor to use or how much scope. Clearly a 35 lb CQR is very marginal on a 30,000 lb boat.

However his question was, what do you do when your anchor starts to drag? If it is blowing that hard, I am going to be on anchor watch unless I am very, very confident of the set. If things are getting dicy I might start the engine and have it idling. If chain rode there is less worry about tangling the rode in the prop, a low power boat can idle in gear and take some of the strain. If you are single handed, recovering the anchor while motoring up to it is going to be very difficult - good time to have a wireless control for the windlass, so you can drive and recover chain at the same time.

Clearly a 35 lb CQR is very marginal on a 30,000 lb boat.

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I think this needs to be discussed further. I disagree BTW, I think it is adequate. I think we forget what the recommended size is before we double the weight for whatever reason.

In a different topic about anchoring I explained the important factors when it comes to anchoring.

What is important is the frontal surface of the boat, i.o.w. how much surface of the boat is in the wind. The wind results in a force on the boat that pushes the boat backwards. You also have surfaces that push the boat sideways, but those forces won't cause your anchor to drag.
It is possible to calculate the force of the wind (in N) and once you know that force you also know how much holding power you need to have in order not to drag.
That holding power is both the holding power of the anchor and the chain. The chain is easy to calculate, it is the weight of the chain (in mtrs) in Newton. The holding power of the anchor is given by the manufacturer for each type of sea bed, if the anchor is set well.
However...........if you raise the shank of any anchor above 25 degrees off the sea bed the anchor does not have any holding power at all anymore, it will drag, no matter which anchor you have.
Most anchors however can and will reset quite easy, the CQR is notorious for not resetting that well.

Keeping that shank on the sea bed is therefore important and you do that with the anchor chain. The less chain you have the less weight you have in the water and if the wind is strong enough it will simply raise that whole chain off the bottom. The shorter the chain the steeper the angle of the chain with the sea bed and that results in lifting the shank off the sea bed, causing the anchor to drag.
If you have more chain on in the water two things happen. First of all you have more weight in the water, which resists the force of the wind, but also the angle of the chain with the sea bed, even if the chain is fully off the sea bed, is less. That means that if that angle of the chain remains below 25 degrees it can also not raise the shank to the 25 degrees and the anchor therefore will still have some holding power.
Of course you will need to take the pitching of the boat in bad weather also in consideration, but I will keep it simple.
To make matters easy they came up with the 3 : 1, 5 : 1, 7 : 1 and 'give it all you've got scope'.

Others have already stated that 75' of chain is enough if you anchored in 5' depth, but not if you anchored in 25' of depth.
If you are interested you can read the 'how to calculate the required amount of anchor chain' in this topic
anchoring-technique-three-questions.69016/page-6

If I found myself in 50kts of wind I would want 7/1 at a minimum. 10/1 if I didn’t have all chain rode. During the summer months you won’t find that much room in our anchorages here in the PNW. Fortunately, we have very calm winds during summer. Not the same in winter. State Parks of Washington actually pull their docks for the winter due to difficult conditions.

SteveK said:

I think this needs to be discussed further. I disagree BTW, I think it is adequate. I think we forget what the recommended size is before we double the weight for whatever reason.

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Recommended size depends on the conditions you're sizing for. The size chart for a CQR doesn't tell you the assumed wind strength, so as far as I'm concerned, the chart means nothing. They could easily be assuming you'll always anchor with 7:1 scope in a perfect bottom and no more than 20 kts of wind.

Various other charts give more info. Rocna indicates a mediocre bottom and 50 kts of wind as their sizing criteria. Mantus gives different sizes based on expected wind speed. And all of them recommend a significantly bigger anchor for a 30k lb boat assuming it's around 40 feet despite those anchors being better performers than a CQR.
As an example my 73 lb Vulcan is 1 size above recommended, not anywhere near double. For my boat Rocna recommended 55 lbs. Mantus says 55 or 65 depending on which wind speed column you look at in the chart.

To answer the specific OP question, what I'd do personally is: Start engine, let out more chain, keep watch, and if you haven't already, set an anchor alarm. I'd also dig out the cheap golf laser rangefinder I keep on board and take & plot some bearings with distance, if possible.

SteveK said:

I think this needs to be discussed further. I disagree BTW, I think it is adequate. I think we forget what the recommended size is before we double the weight for whatever reason.

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I'll say only that I had a 35 lb CQR on a 14,000 lb boat and it was inadequate. In the Virgin Islands (very clear water) I watched a CQR drag along a sand bottom for a hundred yards on its side. In the same bottom a Bruce dug in with 4 feet. There are much better anchors than either now, and if you are planning to anchor in 50 knots of wind, then 50 or 60 lbs is closer to right.

Still, any anchor will drag, and the question was, "then what?"

Years ago smaller than 30 foot boats carried Danforth. I know that was on the boats I had then. They held.
Last two boats Bruce, when look around marina, many have Bruce.
I dunno, until I experience a failure, I will not switch.
The point I was trying to make is the 35lb CQR while not popular anymore has worked for decades with boats of the size we are discussing.
By all means, upgrade the basic anchor and chain, but don't claim it needs to be done.

What to do in that situation.....

Start the engine and prepare to maneuver.

If there is room, let out more chain - lots more - as much as you can.

If there isn't room, see if you can hold station, keeping the anchor in it's current location, so just taking the tension off the chain.

If you can't hold station, then try to retrieve the anchor, but that may be quite difficult (and dangerous) of you are getting pushed around a bunch.

Also keep in mind that if you let out more chain and it doesn't hold, you now have a lot more chain to haul in, thereby increasing the danger during that operation.

The very best choice is to have a big enough anchor and enough scope in the first place to hold, but that's 20-20 hindsight to know how much is enough.

twistedtree said:

The very best choice is to have a big enough anchor and enough scope in the first place to hold, but that's 20-20 hindsight to know how much is enough.

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True. The OPs question is a good one to consider though. Even if your ground tackle is up to the challenge task, in some parts of the world you have to consider other boats anchored nearby. I would feel the need to be prepared in case someone else dragged their anchor down onto me.

We are fortunate to generally have good bottoms, protected water, and benign conditions.

SteveK said:

Years ago smaller than 30 foot boats carried Danforth. I know that was on the boats I had then. They held.
Last two boats Bruce, when look around marina, many have Bruce.
I dunno, until I experience a failure, I will not switch.
The point I was trying to make is the 35lb CQR while not popular anymore has worked for decades with boats of the size we are discussing.
By all means, upgrade the basic anchor and chain, but don't claim it needs to be done.

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Keep in mind that the anchoring choices of the past were often limited both by the anchors available but also by the ability to handle them. Years ago anchor rollers were less common and powered windlasses on small boats were rare. So people were forced to limit what they carried for ground tackle. I'd bet if you asked most of those old school cruisers if they'd rather have a bigger, better holding anchor that's less likely to drag and would work at shorter scope, they'd say yes. They just didn't have the choice in their day in many cases.

I don't look at it as "what I have works". I look at it as being the one time I can directly buy better sleep. So I don't want to think what I have should be good enough, I want to know damn well that it's better than I should ever expect to need.

@rslifkin
You are correct that under 30 footer was anchor without windlass and armstrong limited the gear weight. And it still does.
With a windlass options for heavier is now possible, if needed or wanted, nothing wrong with that.
But to say oversize just for that one time is unnecessary overkill. IMO
Most people are fair weather boaters, go to popular shallower anchorages which are mostly well protected.
So oversizing, choice of anchor becomes a personal choice.

Sitting with the engine idling is not the end all. When the wind comes up it’s usually accompanied by very heavy rain.

Agree let more chain out in advance. 10:1 if you have the room
45# CQR was not enough for my 20k Monk 36 (so was a 20 Kg Vulcan when we added a full fb enclosure)
Starting the engines only works if you can see or have great electronics. You can easily make things worse if you leave it in gear too long. Very heavy rain usually comes with high wind burst blinding you.
If your boat yaws a lot on anchor, a little bad timing will have you sideways when you get slammed by a big gust. Go one size bigger than the size chart suggests. Two sizes if you normally cruise in soft ooze like the Carolinas.

The instruments are another consideration. If the holding is poor, or the weather forecast to be bad, I will leave the instruments on. I'll have a route already entered to leave the harbor. I'll have a waypoint marked on top of the anchor (good practice to do that every time). That way I can get up and already know where I am, what is happening, which way to go, where the anchor is, and where anyone else is that is AIS equipped. Radar too, though in really nasty conditions it may not do much good. Switching all that on, waiting for it to boot and acquire the info can take time when time is very valuable.

Solo_Nomad said:

I was recently anchored in a decently protected Cove. I had about 75 ft of chain out on a 35 lb CQR that was firmly set in soft mud. My boat is about 28,000 lb dry, more like 30,000 lb fully loaded; fuel, water, provisions, etc.

The second night an unforcast storm came through the area. I think we were in the center of it because we got winds gusting to 50+ mph with sustained winds in the high 30s to mid-40s. The anchor held at first; then it just let go.

Please don't discuss the CQR anchor; I'm replacing it and I'm not trying to start an anchor discussion.

Also, I'm not a noob I've been through storms at anchor. However, this was my first anchor drag. An early thought, as it became apparent that the storm was intensifying, was to start the engines to hold the boat in position, but things happened very fast after those initial seconds.

My question is: what are you doing during a storm like what we experienced? We were awake, I was at the helm station, the secondary anchor was deployed, but would not set. What do you do?

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Sounds like you did the only thing you could do - use the engine(s) to relieve pressure on the anchor. Once the anchor cuts loose, adding more scope is not likely to halt the drift. Dropping a second anchor was probably a mistake - no way it could set, and more likely to foul something important and prevent you from getting underway. Don't do that next time.

I do have a question for you. How the heck did you get a CQR to set in soft mud? I know you don't want a peanut gallery, but 75-feet of rode sounds short unless you were in 10-feet of water (taking into account your bow rise).

Peter

DDW said:

The instruments are another consideration. If the holding is poor, or the weather forecast to be bad, I will leave the instruments on. I'll have a route already entered to leave the harbor. I'll have a waypoint marked on top of the anchor (good practice to do that every time). That way I can get up and already know where I am, what is happening, which way to go, where the anchor is, and where anyone else is that is AIS equipped. Radar too, though in really nasty conditions it may not do much good. Switching all that on, waiting for it to boot and acquire the info can take time when time is very valuable.

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Good point. My policy at anchor even in good weather is chartplotter either on or in standby (near instant wakeup) at all times, fume detector left on and keys in the ignitions. And if we're awake the VHFs are usually on as well.