Do you dig your anchor in ?

[Storyline]

I guess on average we spend around 30 - 40 nights at anchor during the sailing season on the west coast of Scotland. Like many others, I suspect, we quite often watch new arrivals in the anchorage laying their anchors. It always amazes me that the overwhelming majority of people drop their anchor, gently motor backwards and then start looking at transits.

I have got to know what it takes for us to dig our anchor in and it goes something like this:

Wait for/encourage boat to line herself up to the direction we want to anchor.
Put engine into reverse. At 1800 revs the cable starts to come up. At 1900 revs the cable starts to get taut and the anchorplait snubber starts to stretch (I do not know how much catenary we have). At 2000 revs we are on the anchor so we start to check transits and my wife has her foot on the chain so she can feel what the anchor is doing. At this point we usually move a metre or two backwards and normally the anchor digs in. If in mud we might still move a little bit back then stop, if in sand we stop completely. If there is not much wind forecast I usually then just increase the revs up to 2200 just to check all is OK but if there is anything more than a F6 forecast I give it full welly for 30 seconds or so to be certain.

The only reason we do not always dig the anchor in at full revs is that the Rocna will sometimes pull out in muddy bottoms and it might take a few goes to get fully on which seems pointless on still nights.

As said above, this behaviour in other boats is very much the rarity.

What do you do ?

 

[stevebrassett]

I sometimes do and sometimes don't - it doesn't seem to make any difference on the East Coast. The mud just sucks the anchor down.

 

[Storyline]

Yes, you are lucky. I should have added that option (when you know the anchorage well and you are going to stay put whatever you do)

 

[Resolution]

Saumur2
You describe exactly what I have been doing this summer, with 99% success on a delta anchor. 42 foot boat.

But you missed out the first bit of the process. What I find really difficult is getting the anchor onto the bottom in the right place and avoiding dropping a load of chain on top. Our windlass is so slow that it can take ages (several seconds?) between the command "Drop" and it reaching the bottom, and I always seem to jump the gun with getting into reverse.

 

[stevebrassett]

One thing I have never really understood is that people dig the anchor in nicely when they arrive, but what happens when the tide turns? My anchor just resets in the mud, but then I didn't have to dig it in anyway.

Do people re-dig in their anchor? Does it reset itself (in which case why the need to dig it in in the first place)?

 

[toad_oftoadhall]

One thing I have never really understood is that people dig the anchor in nicely when they arrive, but what happens when the tide turns? My anchor just resets in the mud, but then I didn't have to dig it in anyway.

Do people re-dig in their anchor? Does it reset itself (in which case why the need to dig it in in the first place)?

+1

 

[jdc]

Be gentle!

I think you are maybe over cautious if you do what you describe every time. It depends on what I know of the bottom type and holding.

If on sand or mud with good holding then all I need to do is make sure the chain is fairly straight and the anchor has started to bed in, and then leave it alone. I find that this gentle approach seems to bed it in just as well as, and I rather suspect a bit better than, using a lot of revs. I also find that my anchor often doesn't set, and certainly stands a greater chance of picking up a ball of weed, if dragged across the bottom at any appreciable speed. If strong wind is forecast we leave it alone for a bit (10 mins?) and then apply maybe 1800 rpm to be sure. But I do not expect it to move at all on applying the revs.

If on poorer holding, eg on weed or boulders, the technique is exactly the same, except that now there's a good chance that the anchor will drag or pull out on applying the revs, so I always apply reverse and may have to try anchoring a few times.

What seems to be key - at lest with my set-up - is letting it bite quite gently and slowly before applying maximum force, so if you were to observe us you might think us cavalier, but there method and experience behind the technique.

PS: One thing we definitely do differently from you is that my other half, who is quite petite, 'drives' while I do the heavy stuff - anchor handling, or picking up mooring or stepping onto the pontoon etc. Physical strength is not half so useful at the wheel as it is on the foredeck.

 

[jdc]

One thing I have never really understood is that people dig the anchor in nicely when they arrive, but what happens when the tide turns? My anchor just resets in the mud, but then I didn't have to dig it in anyway.

Do people re-dig in their anchor? Does it reset itself (in which case why the need to dig it in in the first place)?

You make a good point, but I think the reason that it's still useful to dig it in is where there is weed around. Once the anchor has got under the weed and into the sand or mud then it will usually reset itself fairly well. The difficulty is getting it through the weed - or being confident that it has - hence the need to test it. The direction of the pull not being that important.

 

[mainsail1]

One thing I have never really understood is that people dig the anchor in nicely when they arrive, but what happens when the tide turns? My anchor just resets in the mud, but then I didn't have to dig it in anyway.

Do people re-dig in their anchor? Does it reset itself (in which case why the need to dig it in in the first place)?

IMHO this resetting at the turn of the tide folklore is just that. If the anchor has been dug in I suspect it just stays put on the turn of the tide. If it has not been 'dug in' it will skip around at the turn of the tide or indeed whenever the pull is exerted from another direction, such as when the wind shifts.

 

[Storyline]

IMHO this resetting at the turn of the tide folklore is just that. If the anchor has been dug in I suspect it just stays put on the turn of the tide. If it has not been 'dug in' it will skip around at the turn of the tide or indeed whenever the pull is exerted from another direction, such as when the wind shifts.

Yes, I totally agree. The tide can never exert anything like the same forces it takes to lift the chain completely and dig the anchor in. The point I was making in the first post is that it takes a huge amount of energy to lift all the chain and actually lie to the anchor. All that happens when the tide turns is that some of the chain moves - I suspect it might move all the way to the anchor but the tide will not lift the chain.

 

[vyv_cox]

The point I was making in the first post is that it takes a huge amount of energy to lift all the chain and actually lie to the anchor. All that happens when the tide turns is that some of the chain moves - I suspect it might move all the way to the anchor but the tide will not lift the chain.

Have you tried it? It doesn't take a huge amount of energy to move chain, even on dry land. In order to prove a point I dragged my 60 metres of 8 mm chain in a straight line along a compacted rock/sand yard this year. I did have to pull hard but I managed it, even at my advanced years. Pulling one end around in a loop to reverse it was easy.

In the Med the clear water allows you to see what is happening to the chain, especially by swimming along it, which I do frequently. A wind shift will cause my typical 30 metres of chain deployed to turn to the new direction in minutes, even in winds as light as F 2 - 3. It may well take rather more wind than that to turn the anchor but it most certainly does so. I find the once the anchor is dug in it tends not to rise to the surface and rebed, just swivels around the tip of the flukes or somewhere close.

 

[toad_oftoadhall]

The tide can never exert anything like the same forces it takes to lift the chain completely and dig the anchor in. The point I was making in the first post is that it takes a huge amount of energy to lift all the chain and actually lie to the anchor. All that happens when the tide turns is that some of the chain moves - I suspect it might move all the way to the anchor but the tide will not lift the chain.

So why bother digging the anchor in with the engine?

In the unlikely event "a huge amount of energy lifts all the chain" it will dig itself in then - and you'll be awake by that point for sure.

 

[GHA]

Usually drop the hook and slowly let the boat drift back easing the chain out as it goes. Then quickly let out about twenty feet of chain, tie off and give some revs backward, almost always 10 tonnes of boat will stop with a bang and I can relax.

 

[GHA]

(in which case why the need to dig it in in the first place)?

To see what the holding is like. If it sets fine once then I reason that it will probably continue to do so.

 

[prv]

Our windlass is so slow that it can take ages (several seconds?) between the command "Drop" and it reaching the bottom

One good reason not to motor the chain down.

I know mobos often do it because their foredecks are inhospitable places (like climbing out of your car window onto the bonnet) and they operate the windlass by remote control from the helm. But on a sailing boat where one operates the windlass directly, at the bow, it makes far more sense to let out chain using the clutch rather than the motor.

I only use the "down" button for fine adjustment - walking the anchor out past its balance point ready to drop, transferring tension onto the snubber, or manoeuvring it into position for stowage.

Pete

 

[prv]

Usually drop the hook and slowly let the boat drift back easing the chain out as it goes. Then quickly let out about twenty feet of chain, tie off and give some revs backward, almost always 10 tonnes of boat will stop with a bang and I can relax.

I do more or less the same, except if there's little wind and no tide so the initial drift isn't happening, then I apply tickover reverse so that the boat doesn't just lie to a lump of chain.

Pete

 

[vyv_cox]

I always motor mine down, far easier than messing about with the clutch. The Maxwell is sufficiently fast that it all happens quite quickly enough for conventional anchoring and for Mediterranean stern-to berthing the ability to control the windlass from the cockpit, with neither of us on deck, is ideal.

 

[oldharry]

Big fred drift, but relevant. With the recent increase in environmental awareness, I have had a hard time in BORG convincing conservos that our anchors do not damage the seabed. Dragging it backwards to set it is doing just that. OK, few anchorages are in environmentally sensitive areas, yet. It will spread, as they get their teeth into it once more funding becomes available. but RYA has this summer produced advice with help from BORG and the Wildlife Trusts for anchoring in areas of known sensitivity like Studland, which suggests you do not try to plough the anchor in as described above. More importantly the RYA advice is when raising it, to pull the boat up to the anchor under power to avoid dragging it through the seabed.

What does the panel think? I know well enough the need to ensure the anchor has to be set properly as I nearly always choose to anchor somewhere quiet and out of the way for the night, rather than go alongside.

Back on topic, you only have to watch the Jamboree at East Head in Chi Harbour on a Bank Holiday Saturday when the tide turns at 2.00am! Cries of rage, and crunching of expensive Glass fibre echos for half a mile around as boats take up new positions to each other, and the odd one starts dragging through the crowd!

 

[Storyline]

Saumur2
You describe exactly what I have been doing this summer, with 99% success on a delta anchor. 42 foot boat.

But you missed out the first bit of the process. What I find really difficult is getting the anchor onto the bottom in the right place and avoiding dropping a load of chain on top. Our windlass is so slow that it can take ages (several seconds?) between the command "Drop" and it reaching the bottom, and I always seem to jump the gun with getting into reverse.

I suspect it does not matter if some of the chain is over the anchor when you drop it as you are going to pull it straight when you reverse it in. The system we use is wife on foredeck with the windlass controller (her 'precious') and when we get to the desired spot she lowers the chain and signals each 5m to me with hand gestures. I am on the helm and obviously know the depth so can guess more or less when the anchor hits the bottom. I have kept the boat on station up to this point and then I give a few revs astern and let the boat drift back. I have given up trying to drive backwards in a straight line as the chain pays out as it can be difficult - I just let the boat drift backwards and then wait until she lines herself up or sometimes have to manoeuvre her if we are anchoring in a different direction to the prevailing wind. Once we are in the right direction I pull the chain straight using more and more revs.

.....
PS: One thing we definitely do differently from you is that my other half, who is quite petite, 'drives' while I do the heavy stuff - anchor handling, or picking up mooring or stepping onto the pontoon etc. Physical strength is not half so useful at the wheel as it is on the foredeck.

We are lucky in that I have had a new stem head fitting made which the Rocna stows on when we are sailing and has a flappy thing which means that the anchor launches itself when the tension is taken off the chain. All my wife has to do is plug in the controller and press the 'down' button. She is also responsible for all the 'knitting' of the chain stop, snubber & bits of rope to hold the octoplait snubber central in the bow roller. We only have 35m of chain in our top anchor locker and the remaining 35m is in two other lockers further aft so if we need to lay more than 35m I have to do the heavy-ish job of moving chain from one locker to the other (note to self - must devise a system of a roller so the windlass can pull it through)

Have you tried it? It doesn't take a huge amount of energy to move chain, even on dry land. In order to prove a point I dragged my 60 metres of 8 mm chain in a straight line along a compacted rock/sand yard this year. I did have to pull hard but I managed it, even at my advanced years. Pulling one end around in a loop to reverse it was easy. .....

Sorry, I did not make myself clear. I was not talking about moving the chain, I realise that it can move easily along the seabed but the amount of force it takes to lift it all. I do not know how much energy the engine puts out but even at 1700 revs in astern (which is enough to push the boat along at 5 knots) it will not lift the chain all the way to the anchor. Somewhere on the boat I have got a formula devised by the theoretical physicist we usually sail with when we were gale bound at anchor one day. Using this he worked out the force needed to lift the last link next to the anchor on a 6:1 scope. It was not enormous but I think it was more than a 3-4 knot tide could produce.

 

[Storyline]

I always motor mine down, far easier than messing about with the clutch. The Maxwell is sufficiently fast that it all happens quite quickly enough for conventional anchoring and for Mediterranean stern-to berthing the ability to control the windlass from the cockpit, with neither of us on deck, is ideal.

So do we. Using the hand controller means my wife can be standing up - if she used the clutch she would have to bend over the windlass and control it with a winch handle. Much more hassle for her. Also standing up means she is able to signal to me what is happening.