When do you set the anchor ?

[Badger]

say I've worked out I need to let out 20m of chain for the depth I am anchoring in. Do I snub the chain and try and set the anchor with a burst of astern when I have let the full 20m out or do I let out half and then try to set it,check it is set with a transit and then let the rest out ? Which way is best please or is there a better way ? Thanks in Advance

 

[Trevethan]

I set the whole 20 metres. then motor astern, gently first then at about 2/3 throttle to set the anchor and ensure no dragging. If you set just half the chain, then your burst of astern can pull the anchor upwards.

Least that's how I do it.

Suspect different type of sea bed and anchor call for different techniques!

She had a deep, throaty, genuine laugh, like the sound a dog makes just before it throws up

 

[Reap]

I agree...if you let out only half of the required chain then the chances are, the anchor will drag if there is any significant tide or wind and if there is no tide or wind then sitting and watching for a steady transit is pointless as just the weight of the anchor/chain alone will hold. Motor slowly backwards (or let the tide/current do the job for you) until the full scope is out and snubbed, you can then gently raise the revs to around 2 thirds. Personally I then check the transit whilst still in reverse, if steady I kill the engine and then recheck the transit when the chain has settled.

 

[Jacket]

Was once told that if you're expecting a bit of a blow, let out as much chain as you've got, set the anchor, then shorten up the chain to what ever length you think suitable. The argument was that if you let out lots of chain before trying to set the anchor, the pull is more horizontal so the anchor tends to dig in deeper. Apparently this was backed up by some tests.

This method has always worked for me when I've been expecting bad weather. Unfortunately there's no way of telling whether or not the anchor would have dragged if I'd set it in the normal way.

 

[snowleopard]

i don\'t know why...

but i've found that trying to set the anchor straight away often results in dragging. if i let everything settle in for a while before using astern to dig the hook in i have much more success. maybe it's because it gives the gear time to get straightened out and pointing the right way.

my bower is a delta and i never use less than 5:1 scope.

 

[Guest]

I'd set it as described by the others except increasing gradually to full revs astern and if possible with the full strength of wind and tide pulling in the same direction. I'd rather have to heave a bit getting it out of the ground in the morning, having got a blissful night's sleep, than drift in the night. This force on my boat seems to equate to something like that exerted by a 20-something knot wind (if you don't believe me, experiment to see what strength of wind you can motor astern into and still make way at full revs - that is the strength of wind you are simulating with the engine). This leaves me reasonably happy that the anchor will be sufficiently well bedded to cope with a turn of the tide (and wind).

This treatment will usually pull the anchor out of the ground if the 20m only represents a 3x scope is used - that means that a 20-something know wind would probably pull the anchor out too. If only 3x is possible, then bed the anchor in as described with 4x (ie. about 28m), then shorten it to 3x once it's dug in.

That's my approach, anyway.

 

[jcr]

Lets say that the engine on the average yacht can provide 50kg of thrust in reverse. If a very long? length of heavy? chain is set, that 50 kg will only provide enough power to lift part of the catenary from the sea bed, and the anchor will feel very little, if any, pull. It is really another trial and error situation, considering depth, scope and weight of chain. If a blow is expected, I would try to set my anchor/chain combination at a 3:1 scope, then deploy the rest. If a chain rope combination is used then a longer scope may be better.

 

[Jacket]

OK, I forgot to mention that I use an anchor rode rather than chain, so the amount I let out has little effect on the amount of pull on the anchor, just on the angle.

 

[Badger]

Is an anchor rode another name for an angel or a chum ? How do you use them ? Where can you get them from, I haven't seen them in the chandlers ?

 

[Jacket]

Nope, its just another name for a rope, rather than chain, anchor cable. May be out of daye now- I picked it up from my grandfather and great-uncle.

 

[MedDreamer]

Americans still use the word rode . When I first read it on a forum I thought it was a spelling mistake!!. Then I saw everyone else used it too.

Martyn

 

[wpsalm]

Did ya ever wonder how they set the anchor before engines ???

 

[Trevethan]

you'd set a couple of those square sails aback - Reckon making a fore and aft vessel reverse under sail is a lot trickier than a vessel with a square rig

She had a deep, throaty, genuine laugh, like the sound a dog makes just before it throws up

 

[Jacket]

Backing the main? So just make sure you've got a big strong ape in the crew, who doesn't mind being beaten around the head with the boom.

 

[charles_reed]

Re: When do you set the anchor?& other ramblings

As I sail single-handed my methods might not suit others.
The boat is 9.5m oa with a design weight of 3000kg (31'/3tons)

If the bottom is soft sand or mud I decide the anchor point, sail or motor over it to check depths or any obstructions and then bring the boat up, head to wind, cut the motor or drop the main and go up forward and hang the anchor over the bow, only letting go when it's no longer making way through the water, I let out, as quickly as possible, sufficient chain scope for the anchor to touch bottom, then slowly pay out chain as the boat goes downwind at exactly the same rate as she's travelling. Most boats adopt a 40 degree attitude to the wind (watch out for starting to sail away again) - I let out a minimum of 3:1 and usually 5:1. Make fast the chain and you should straighten out the chain and bring the catenary off the ground - you'll see and feel all this. To avoid losing fingers between chain and cleat quickly hang out about 2m of chain before making fast.

Using rode alone you need between 5 & 7:1 to get any decent hold.

The effect of bringing the boat to a halt should be sufficient to set the anchor - though in low wind conditions you might like to apply GENTLE reverse, sufficient to straighten the chain and lift the catenary off the seabed.
Don't whatever you do use reverse when in thin sand over rock - you'll have the anchor out and it's very unlikely you'll get it to dig in again.

It is sensible practice to anchor and pick up under sail at least 50% of the time - though short-tacking up between 40 odd parked boats in Coveen, between St Agnes and Gugh, at twilight can cause others and oneself a degree of hysteria.

If one's short of swinging space, I'll set 2 anchors at 90 degrees to each other, dropping the bower first and either motoring or sailing over on extended scope to drop the kedge. Under crowded conditions or where there's a chance of fouling I use a 10m line onto a pickup buoy - in waters where you're likely to find French boats be wary of having your pick-up used as a mooring.

On rock I'm much more circumspect with letting out the catenary, constantly check in the boat so she doesn't pick up to much speed and I'd not tempt providence with using reverse, certainly not until the anchor's had a couple of hours to bed in. In any case you can easily hear an anchor dragging on rock.
If possible try and lay your chain parallel to the rock-lines and keep any fibre rode well out of reach of rocks. If there's plenty of room I usually allow about 7:1 on rock, but in rivers, like the Guadiana, you have lot of rock and shallow water and only a few pools with any depth, combined with a tidal rise 7 fall of 1-1.5m. Under those circumstances two anchors out (upstream and downstream) need to be augmented by a crafty line ashore to a substantial tree, preferably NOT across the navigated channel.

It's quite useful, in less murky waters the the British Isles, to paint the upper surface of your anchor white (hard luck if you've a fisherman, Danforth, Brittany, Fortress or US Navy). It allows you to see the position and attitude of the anchor - the two most frequent reasons for plough-type anchors not setting are:
1) Upside down
2) On their own chain or with a chain-wrap.

The anchors I have are a 25lb CQR lookalike, a 6kg Delta and a 10lb Danforth. I have 65m of 8mm chain, 50m of 7mm chain, 20m of 5mm chain, 100m of 25mm Octoplait rode, 50m of 12mm Octoplait rode, plus about 180m of other assorted line.
I occasionally use a manual Anchorman winch, usually to break an anchor out. After 24 hours of <60 knots you'll find the anchor has tried to dig down to the Antipodes and you really need some power to get it up.
One can expect a fouled anchor about once every 4 months - you can usually get the anchor back using scuba gear, but the chain quite frequently has to be sacrificed to Poseidon.
Anchoring is definitely more challenging in tidal waters, you have to lay out to suit the currents, and the difference shows with anchoring in the Med being undisciplined (to put it mildly).

When cruising I anchor about 4 nights out of 5, usually in between 6-18m of water.

PS The Coveen incident was totally kosher, when I'd run out of diesel due to overnight teasing by the Smalls pod of dolphins (wicked women) - I'd arranged, through Falmouth CG to have 25l of diesel waiting for me by the submarine telephone line, so I could get on to Moulin Blanc.

 

[Viking]

Re: When do you set the anchor?& other ramblings

Could I ask, where do you keep 135M of chain and these anchors on your boat? and keep it balanced?

 

[charles_reed]

Stowage

Bower in the bow-roller,
Delta in port saloon locker, aft of the keel
Danforth strapped down in engine well
65m 8mm chain and 25mm Octoplait in chainlocker in the boat's forefoot
50 7mm chain in starboard bilge forward of keel
rest of the chain and octoplait, boxed, in the engine well.

Needless to say the boat's well over her marks.

 

[ponapay]

I throw the ..

15Kg Bruce over the stern on about 40m of warp, motor up to the nearest rock, jump ashore with another warp (or take the 45lb CQR) secure ashore. The I haul taut on the Bruce to bring her nicely offshore, moored between two anchors.

 

[Badger]

Re: When do you set the anchor?& other ramblings

Charles, what do you think of anchor weights eg chum's angels etc. Do you ever use them ?

 

[Spacewaist]

Interesting article in YM

I think in October or November about a couple anchoring under power, but very much adopting the principles described by Charles_Reed below.

It sounded all very controlled, professional and unstressful; rather different from my experiences with SWMBO. The thing which struck me is the SLOW astern to dig the anchor in.

We plan to try it next season.











A pontification from the Panjandrum of orotund bloviation AD2002