Are we dragging our anchor?

Rivers & creeks

Rivers & creeks

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We're anchored on the Ore river in a marked anchorage. The bottom is mud and no doubt some shell, sand and stones, but mostly mud. We've got 8m of water and 30m of 10mm chain on a Kobra2 over specked anchor. We're a bit new to overnight anchoring and a bit worried. We've been here 10 hours and she's just swung to the new flood and we heard lots of anchor dragging type noises. The wind is light but when we swing round we hear the grinding type noise that sounds like dragging.

Could it be that it's just the chain dragging on the bottom as we are swinging? We just started the engine and put her in reverse to realign all the chain to the new tide direction. There was no doubt that we have a dug in anchor. But as I type this I can hear the dreaded intermittent sound.

We've taken transits and a GPS fix and they "seem" OK, but we're spooked by the sounds.

Any thoughts?
 
Welcome to the nervous anchoring club. If you are well dug in and the transits are OK you should be able to relax. It is over thirty years since I anchored in the Ore - opposite the quay! - and it can be a bit worrying but I can't remember if the bottom was noisy, though I wouldn't be surprised if it were. You should be fine, but it may be a restless night. A chain can make a lot of noise without dragging, and the sound is subtly different.
 
The middle of the night rumble is one of the disadvantages of all chain rode. Why not use a rope snubber tomorrow night and isolate the sound.

The other view is that it's a good alarm to wake you to check things as the tide turns. I'm for a peaceful night, with a good anchor and a reasonable length rode. If you are worried, run out a bit more chain.
 
What you are hearing is the rode scraping along the bottom as you turn. About 1/3 of the chain lies along the bed in the direction you lie, when the tide turns, so do you & the pull on the chain is in the opposite direction. The anchor probably isn't affected & the chain runs in a big U shape back to the anchor. As the tide increases the pulll on the chain increases & the shape of the U chnages with the arm of the U attached to the boat getting longer & the arm connected to the anchor shortening.

Very often the weight of chain on the bed is enough to hold you & the anchor never resets, but you will hear the vibrations in the chain as it is dragged around the sea bed. Relax & go back to sleep. have a good night.

Edit: Stuff a big chunk of old rag or towel under the chain if you want quiet.
 
If in doubt... Let more out.

30 meters out in 8 meters is dubious IMHO.... I prefer at least 4 or 5 times max depth.

I would lay out another 10 meters..

But as the other have said your still gonna get lots of noise as the chain rumbles over the ground.. Especially at the turn of the tide... You could snub whereby you tie off the chain and let a bit more out so it forms a small loop between the boat and the stem head .... Which will eliminate most noise.

If there is any real tide... I would be a lot more comfortable myself with another 10 meters out...
 
As others have said the sound is just the chain, not the anchor moving. With a rope snubber (which you should use anyway as it increases holding) will stop most of the noise.

My only slight concern is your scope is reasonably low. Scope is measured from the bottom, to the bow roller so it will be 1.5m or so greater than the depth of water.

This means you only have slightly more than 3:1. You don't mention the wind strength, but for overnight anchoring I would be more comfortable with a bit more scope.

Edit: I see photodog had the same thought while I was typing my post. Great minds......
 
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Thanks everyone for the replies. I went up and checked the chain and there's 40m out not 30m as I mistakenly said, but that includes the 4 or 5 metres from the windlass to the water. We always use a short length of rope on a chain hook so that the windlass isn't taking the strain, but the chain still runs over the bow roller. I can see how running the rope over the roller will dampen the noise.

That seems to give us about 4.1 of chain to water depth, the maximum depth we saw at high water was 10.5m so that will reduce the ratio.

Damned noise is there occasionally. Still, it's just the chain, right? :)
 
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The Lazy Kipper said:
Thanks everyone for the replies. I went up and checked the chain and there's 40m out not 30m as I mistakenly said, but that includes the 4 or 5 metres from the windlass to the water. We always use a short length of rope on a chain hook so that the windlass isn't taking the strain, but the chain still runs over the bow roller. I can see how running the rope over the roller will dampen the noise.

That seems to give us about 4.1 of chain to water depth, the maximum depth we saw at high water was 10.5m so that will reduce the ratio.

Damned noise is there occasionally. Still, it's just the chain, right? :)
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Let us know in the morning;)
 
The Lazy Kipper said:
Thanks everyone for the replies. I went up and checked the chain and there's 40m out not 30m as I mistakenly said, but that includes the 4 or 5 metres from the windlass to the water.
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If maximum water depth was to be be 10.5 meters, then it would better to have the 42 m of chain at the water line, but what you have would be OK. Its always a good idea to dig the anchor in with reverse power. I increase the power to about 1000 rpm and hold it like that for a short period.

If you are dragging your anchor its quite obvious as usually the chain will be running staright out in front of the yacht if the anchor is still on the end of the chain. Noise is normal. I would increase the length of the nylon snubber so that it is running over the bow roller (chafe protection). That helps reduce the noise of the anchor chain through the hull.

You will grow in confidence and learn how the boat sounds and feels at anchor the more you do it. I have anchored many, many times and I don't worry. However, when I started sailing with my family I remember that I was worried, it was irrational, but never the less, the worry was there. Now I anchor confidently with the family as well.
 
When that happens I often wait until the tide gets going properly, then put the helm over hard to give a good shear in both directions. This helps to stretch the chain out in the new direction in one go, instead of the "drip drip" effect of doing it on it's own. It also gives you a bit of confidence that the anchor is set.
You're awake any way, might as well sit in the cockpit and enjoy the night scene with a cup of tea:)
 
There is dragging and there is plowing.
We have a CQR, that is a plow. Even in good ground, but with a lot of wind, we managed to plow 30 yards in three days of storm. ( 65 m chain in 4 m water depth ) The water is clear here, after the storm I could see the furrow.
When dragging, the boat puts its broadside to the wind. Acting time. Presto.
In all those years I have learned to sleep even with the grinding sound. I think that sleeping ( without been drunk ) suspecting from experience that the anchor spot or weather is bad, the mind is in a state that lets you wake up when something is wrong. Takes some time.
 
I have an iphone and use 'DragQueen' which is an anchor alarm app.

It uses the phone's GPS to determine if the anchor is dragging. If the boat is moving, it sounds an audible alarm.

It's heavy on the phone's battery, so the phone needs to be plugged into the ship's battery for overnight use, but otherwise seems to work well. However, I have not yet had an anchor drag so I have not used the app in anger.

Gitane
 
Thanks everyone for the valuable advice - and reassurance. We didn't drag, we didn't budge and when the forecast f6 came along, all the grinding noises stopped, I assume because the wind pushed the boat and stretched the chain out and most of it was in the water rather than on the seabed.

In hindsight of course we wonder why we were worrying, but on a previous boat we dragged in spectacular fashion once but we had a really rubbish anchor. To be honest when we heard that sound last night we panicked and assumed the same was happening again. The early replies reassured us and we stopped talking about trying to pick up a mooring buoy in the moonless pitch dark :o

The reality is we feel a hell of a lot more confident in the process, with a bit of luck and some careful reading we'd done a reasonably good job of getting the anchor set. Lack of experience then let us down.

There were lots if suggestions to let more rode out, we weren't sure about this because the river isn't that wide and we were concerned about being pushed into the shallow side when the wind got up?

We'll be re-rigging the subber, I can see how it will dampen the sounds and next time we hear them we'll do the usual paranoid transit checks then just go to sleep!

I also downloaded an anchor watch app for the phone :)

Thanks everyone.
 
Glad you had a good experience.
An anchor alarm is good insurance, it can also be set to wake you if you if the wind changes direction even if you not dragging. This way you can check you are not too close to the riverbank for example.
I prefer a propper marine GPS, but iPhones etc are still better than nothing. Look at IXL drifter which seems better to me than drag queen (but mine is on an iPad as my iPhone does not have GPS)

Often the bank or shore looks much closer from an anchored boat than it is in reality. Motoring around the expected swing circle (slowly, carefully monitoring the depth) before dropping the hook is a good idea. If you record this track on your GPS you even have a record of a known safe circle. When anchored you can see where you lie within this safe circle.
 
Masthead vs fractional rig

I can see some advantages of sail handling with a fractional rig and also note that the trend in newer boats is to carry a fractional rig. I have only had much experience of mast head rigs so where do the big differences lie in sailing performance between the two?
 
smeaks said:
I can see some advantages of sail handling with a fractional rig and also note that the trend in newer boats is to carry a fractional rig. I have only had much experience of mast head rigs so where do the big differences lie in sailing performance between the two?
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Note that if you're not well anchored you may drift into another thread!;)
 
The Lazy Kipper said:
Thanks everyone for the replies. I went up and checked the chain and there's 40m out not 30m as I mistakenly said, but that includes the 4 or 5 metres from the windlass to the water.)
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Always need to count chain scope from the water, not the winch as can be big difference as you note. Also worth remembering many boats set sounder to below the keel depth, so can need to add 2m or so for that.

My rule is 3x scope for lunch onboard, 4x overnight and preferably 5x if going ashore out of sight of boat. More if expect wind and space permits
 
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