Emergency anchoring

Roberto

Roberto

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Following the video of the grounded boat, I am asking myself the following question.


Onshore wind and waves, the boat loses steerage and begins drifting toward land.
One decides to anchor as an emergency measure.
Depth is 100m, the boat has a 100m cable (chain+rope)

When would you drop the anchor ?
Immediately, thinking that after touching the bottom and dragging for a -probably- considerable distance, the anchor would eventually set.
Wait till depth reduces to say 30m -the anchor could hold, but scope would be short.
Wait till depth reduces to 10m (that would be a 10:1 scope).


Also, in which way would the nature of the bottom influence your decision ? (Making the assumption that one still has his head to think about the nature of the bottom).
I mean, if the bottom is sand, I'd be more inclined to drop anchor as soon as possible (smoother waves, etc), whereas if it is rocky (meaning the anchor might well hold with a 1.5:1 scope) I'd be afraid of all hell breaking loose with such a short scope with very limited dampening


What would you do, and what other factors would you consider ?
 
Good questions, and I don't know the answers - speed of drift would be one variable which might affect things.

But another thought - would the resistance of chain and anchor hanging from the bows in deep water, or dragging across the bottom in shallower water, help hold her head up into the wind, allowing (maybe) the engine to be used to slow the rate of drift?
 
Roberto said:
Following the video of the grounded boat, I am asking myself the following question.


Onshore wind and waves, the boat loses steerage and begins drifting toward land.
One decides to anchor as an emergency measure.
Depth is 100m, the boat has a 100m cable (chain+rope)

When would you drop the anchor ?
Immediately, thinking that after touching the bottom and dragging for a -probably- considerable distance, the anchor would eventually set.
Wait till depth reduces to say 30m -the anchor could hold, but scope would be short.
Wait till depth reduces to 10m (that would be a 10:1 scope).


Also, in which way would the nature of the bottom influence your decision ? (Making the assumption that one still has his head to think about the nature of the bottom).
I mean, if the bottom is sand, I'd be more inclined to drop anchor as soon as possible (smoother waves, etc), whereas if it is rocky (meaning the anchor might well hold with a 1.5:1 scope) I'd be afraid of all hell breaking loose with such a short scope with very limited dampening


What would you do, and what other factors would you consider ?
Click to expand...

I've always thought I'd go for option 1(100/100) on the grounds that I'd then have more time to sort out/work around the problem. While you're afloat you have a chance,on the rocks you're stuffed!
 
"Never go ashore with an anchor in the pipe" is a bit of merchant seafaring wisdom that gets passed down from one generation to the next.

I suspect that, in practice, one will be trying to get the anchor over as fast as possible; it takes a certain amount of time anyway, and on a foredeck that is trying to pitch you off, it will take longer, so the question may be academic.
 
I'd be inclined to dig out all my warps and fix them to the end of my anchor cable well before I got to close to the shore. So whilst still in 100mtres of water, where the waves may be less than when the seabed shallows, I'd have a chance of setting a sensible scope. At least it might slow up the drift to the shore.

(All spoken from the comfort of my office)
 
Purely hypothetical question.

1. in the med, the depth goes from-800m to 0 quite fast.
2. in our region (Channel),100m depth doesn't exist
3. I would let everything go asap, to use as a drag. Several thoughts
a) this will turn the nose of the boat into the wind
b) 100m rode hanging vertically weighs quite a lot. You cannot handle that amount of rode manually. Trust me, I tried it. I had to lead the chain to the cockpit to turn it around the genoa winch in order to raise the anchor.
 
"The Anchor.

Anchoring at High Speed.

The anchors are the narrow-water navigator's stand-by in all cases of emergency. There is an old sea-saying, 'Never go ashore with an anchor in the pipe', and this should apply to most emergencies. A ship may fail to turn, take a sudden sheer, carry too much way, and engine may fail to go astern . . . . a collision may be imminent -- in all cases the anchors are waiting to be used. Both anchors should be let go and allowed to run out their cable until sufficient is out to enable the anchors to hold. They are then snubbed and perhaps alternately veered and snubbed so that the ship gradually loses her way."

Theory and Practice of Seamanship, G.L. Danton, p.24, London 1962
 
If the anchor drags any distance on a short scope there is the risk that it will become choked with weed or rubbish and then fail to set. I would be inclined to lower about 25% of the scope from the bow then pay out the rest when the anchor touches. Perhaps stop off the chain at the roller with light line and flake the rest on deck so when the anchor catches the stopping will break.

I have successfully anchored in deep water using a light anchor and warp attached to the end of the main anchor chain so that the weight of the chain leading almost vertically kept the the warp at a shallow angle at the anchor, but this was for convenience in fog and a force 4 to 5, not a lee shore emergency. This is a variation on a mooring method used for oceanographic instruments.
 
I found myself in a situation similar to your question....

I was on a 38 foot new boat motoring along a lee coast with significant swell and wind. Depth was around 15m and the engine failed. Progress to windward under sail was not possible due to the extreme swell that had built up... RNLI contacted and question raised with them...should I drop the anchor to slow/stop progress onto shore or wait for them to arrive on the scene to undertake a tow. Interstingly their view was if you have a large scope of chain deployed taking my situation in consideration getting it back onboard will take time and it could be dangerious on the foredeck. Offcourse the anchor and ground takle could be released overboard and lost, but again it would still be a dangerious excersise. They view and my view at the time was to leave the anchor until the very last possible option. For your information depth below my keel when the RNLI arrived was 3 m and dropping fast, but to engage the tow took only minutes.
 
minkysailing said:
I found myself in a situation similar to your question....

I was on a 38 foot new boat motoring along a lee coast with significant swell and wind. Depth was around 15m and the engine failed. Progress to windward under sail was not possible due to the extreme swell that had built up... RNLI contacted and question raised with them...should I drop the anchor to slow/stop progress onto shore or wait for them to arrive on the scene to undertake a tow. Interstingly their view was if you have a large scope of chain deployed taking my situation in consideration getting it back onboard will take time and it could be dangerious on the foredeck. Offcourse the anchor and ground takle could be released overboard and lost, but again it would still be a dangerious excersise. They view and my view at the time was to leave the anchor until the very last possible option. For your information depth below my keel when the RNLI arrived was 3 m and dropping fast, but to engage the tow took only minutes.
Click to expand...

I wont argue this RNLI advice, well yes I will! That does sound a bit like the hero saving the heroine at the last minute in a Hollywood film, not a risk I would like to gamble on. If all the chain is on the seabed and you have a good scope of rope between there and the boat, tie a couple of fenders to the end of the rode and leave the anchor and rode for collection in better weather.

No? Not comfortable with working on the foredeck to do that once rescue arrives? Ditch it (the anchor and rode) the boat and your life is far more valuable than the ground tackle.

PS glad to hear your experience had a happy conclusion.
 
A few years ago a well-known Lymington sailor had an emergency in a SW gale off Beaulieu (sails u/s, rope round prop, children on board in a panic) so he dropped the anchor and pulled up just off the shore. The inshore lifeboat had been called out and, after a bit of hassle in getting a line attached duly took him in tow back to Lymington. Half way up the river they were all surprised and embarassed when the anchor, which they had completely forgotten to raise, caught on the river bottom and brought them to a shuddering halt!
 
galadriel said:
I wont argue this RNLI advice, well yes I will! That does sound a bit like the hero saving the heroine at the last minute in a Hollywood film, not a risk I would like to gamble on. If all the chain is on the seabed and you have a good scope of rope between there and the boat, tie a couple of fenders to the end of the rode and leave the anchor and rode for collection in better weather.

No? Not comfortable with working on the foredeck to do that once rescue arrives? Ditch it (the anchor and rode) the boat and your life is far more valuable than the ground tackle.

PS glad to hear your experience had a happy conclusion.
Click to expand...

I agree. That sounds like crazy advice to me. Just drift and hope the lifeboat gets to you in time?!! I'd clip on, go forward, and get that bl**dy anchor down. Depending on how it's rigged, it's not usually the worst job on the foredeck. If it's in a bow roller, at least, then it really shouldn't be so difficult. On my boat I'd just pull the pin and let the windlass let out the chain.

If it were really impossible to get to the foredeck (almost unimaginable, if you've got jacklines rigged, but suppose), then I'd toss the kedge off the stern. Surely there are a few things which can be done besides passively get blown onto a lee shore.

If for whatever reason it's dangerous or difficult to raise the anchor again once a tow line is rigged, I'd just jettison it. Just cut the snubber and let the chain run out as the lifeboat pulls you off the shore. There's nothing difficult or dangerous about that operation. What's an anchor, compared to your boat?

Imagine the RNLI miscalculated, and you end up on the beach (or worse, on the rocks), after having just stood there in the cockpit with your p***ck in your hands, waiting for them? No way I would do it that way.
 
minkysailing said:
I found myself in a situation similar to your question....

I was on a 38 foot new boat motoring along a lee coast with significant swell and wind. Depth was around 15m and the engine failed. Progress to windward under sail was not possible due to the extreme swell that had built up... RNLI contacted and question raised with them...should I drop the anchor to slow/stop progress onto shore or wait for them to arrive on the scene to undertake a tow. Interstingly their view was if you have a large scope of chain deployed taking my situation in consideration getting it back onboard will take time and it could be dangerious on the foredeck. Offcourse the anchor and ground takle could be released overboard and lost, but again it would still be a dangerious excersise. They view and my view at the time was to leave the anchor until the very last possible option. For your information depth below my keel when the RNLI arrived was 3 m and dropping fast, but to engage the tow took only minutes.
Click to expand...


To me, that sounds like crazy advice. Obviously it depends on conditions and distance from assistance. In a recent lifeboat call-out on the west side of the Outer Hebrides, it took the lifeboat, from Stornoway, five hours to get there. I would always anchor, if it was possible, and worry about raising it or slipping it when the time came.
 
Roberto said:
Onshore wind and waves, the boat loses steerage and begins drifting toward land.
One decides to anchor as an emergency measure.
Depth is 100m, the boat has a 100m cable (chain+rope)

When would you drop the anchor?
Click to expand...

I had given this a bit of thought, and would drop the anchor and about half my scope, depending on the depth.
Even if the anchor doesn't hit bottom the drag would help point the nose to the sea and slow the boat a bit. When the anchor does touch the drag will slow the boat some more then hopefully bite. I can then let out the rest of the rode.

If I take your 100m depth scenario, I would probably put out my sea anchor first, but there are a lot of other factors to take into account, such as how far is it to shore.
 
LadyInBed said:
I had given this a bit of thought, and would drop the anchor and about half my scope, depending on the depth.
Even if the anchor doesn't hit bottom the drag would help point the nose to the sea and slow the boat a bit. When the anchor does touch the drag will slow the boat some more then hopefully bite. I can then let out the rest of the rode.

If I take your 100m depth scenario, I would probably put out my sea anchor first, but there are a lot of other factors to take into account, such as how far is it to shore.
Click to expand...


Well, if you still have 100m depth then you're not on the verge of going aground. Maybe there is a place or two in the world where depth goes from 100m to shallow pretty fast, but that's pretty rare. I was in the Sea of Cortez in January; there are underwater canyons and some weird gradations of depth, but even there you have a few cables of anchorable ground before you're on the beach.

So if you have 100 metres of chain on board that ought to allow you a fighting chance of getting an anchor set before going aground just about anywhere.

To take not the 100/100 example, but a real live one: Minkysailing was in 3 metres (!) by the time he got picked up by the RNLI. It was 15 metres depth when his engine quit! You can definitely anchor in 15 metres! A 6:1 scope with 100 meters of chain out is a lot more effective than a 6:1 scope with 30 meters of chain out, because of the sheer weight of 100 metres of chain compared to 30. I'd say 15 metres of water would be just about ideal, and that would leave you half a mile off the beach in most places.

So depending on the depth gradations, I would probably not throw the anchor out in 100 metres of water. I would wait until there's a good chance of getting the anchor to set. And I agree with SRM that you would risk fouling the anchor by letting it drag across the bottom. I wouldn't put it down until I seriously intended to set it.

And I'd be getting the spare bower and the kedge ready just in case.


All this is easy enough to say in the warmth of our studies; altogether a different one in the cockpit in the terror of a situation. Still very useful to think it through, though.


I'm actually just about to change my ground tackle, and all this frightening discussion makes me think to go up (yet) another size with the main bower.
 
Maybe there is a place or two in the world where depth goes from 100m to shallow pretty fast, but that's pretty rare.

I take it you have never sailed in the Ionian sea!:)
 
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