machurley22
New member
Hmm.. NM
.
.
anchor scope
- Thread starter Talbot
- Start date
webcraft
Well-known member
Re: Disagree. Completely.
[ QUOTE ]
I guess that I am experienced enough to anchor with what length is sufficient.
[/ QUOTE ]
Your attitude smacks of arrogance, my feline friend. Even very experienced sailors have been know to lose their boats on a dark and stormy night . . .
It is generally accepted wisdom that scope of up to 10-1 may be advisable in extreme conditions. 3-1 is a minimum, to be used for lunch stops or very settled overnight conditions where the holding is good.
Of course, water depth is also a factor . . . in general we anchor in 3 - 8 metres up here in Scotland, so a scope of 5-1 or more does not usually give too big a swinging circle. Problems do arise in the unusual event of crowded deep water anchorages - Tobermory springs to mind, where it is seldom possible to put out as much scope as one would like in a blow.
If I was unfortunate enough to be in a crowded anchorage in 'modern conditions' as so quaintly put, stuck with a maximum scope of 3-1, and winds in excess of 30 knots were expected I would rather put to sea. I think you have been lucky so far . . .
- Nick
[ QUOTE ]
I guess that I am experienced enough to anchor with what length is sufficient.
[/ QUOTE ]
Your attitude smacks of arrogance, my feline friend. Even very experienced sailors have been know to lose their boats on a dark and stormy night . . .
It is generally accepted wisdom that scope of up to 10-1 may be advisable in extreme conditions. 3-1 is a minimum, to be used for lunch stops or very settled overnight conditions where the holding is good.
Of course, water depth is also a factor . . . in general we anchor in 3 - 8 metres up here in Scotland, so a scope of 5-1 or more does not usually give too big a swinging circle. Problems do arise in the unusual event of crowded deep water anchorages - Tobermory springs to mind, where it is seldom possible to put out as much scope as one would like in a blow.
If I was unfortunate enough to be in a crowded anchorage in 'modern conditions' as so quaintly put, stuck with a maximum scope of 3-1, and winds in excess of 30 knots were expected I would rather put to sea. I think you have been lucky so far . . .
- Nick
Ships_Cat
New member
Re: Disagree. Completely.
Perhaps you could describe your experiences anchoring in heavier conditions (say 45 knots plus), the boat(s) and its anchoring equipment. I have stated some of mine. From your suspecting my claims to be arrogance I can only presume that you have considerable experience in the matter and that with solid cruising yachts with heavier anchoring systems.
If we were to put to sea whenever the wind was likely to exceed 30 knots, as you say you would rather do, I have to say that we would get very little anchoring done here. We cannot even leave our hard dinghy unlashed down on deck when at anchor - it is inclined to go over the side if the wind comes up, as it is likely to do very quickly.
John
Perhaps you could describe your experiences anchoring in heavier conditions (say 45 knots plus), the boat(s) and its anchoring equipment. I have stated some of mine. From your suspecting my claims to be arrogance I can only presume that you have considerable experience in the matter and that with solid cruising yachts with heavier anchoring systems.
If we were to put to sea whenever the wind was likely to exceed 30 knots, as you say you would rather do, I have to say that we would get very little anchoring done here. We cannot even leave our hard dinghy unlashed down on deck when at anchor - it is inclined to go over the side if the wind comes up, as it is likely to do very quickly.
John
NigeCh
New member
Re: Disagree. Completely^2
For a sailing person of pedigree who has sailed under Tilman on Baroque to Spitzbergen and still sails a mean lean pre-war racing machine, you then go and sour the apples in the barrel by saying that 3 to 1 is good for all 'modern' conditions.
If Mirelle was anchored with her current gear at the same time and the same place as Mirabella V with a 3 to 1 scope would Mirelle have dragged in the same way as Mirabella V dragged onto the rocks?
The answer is YES. The dreadful downside is that Mirelle would have broken up on the rocks and all for the sake of too small a scope for the combined conditions which were not 'modern' but real conditions.
Have you read Knox's treatises on practical anchoring? (Porridge for tea?)
For a sailing person of pedigree who has sailed under Tilman on Baroque to Spitzbergen and still sails a mean lean pre-war racing machine, you then go and sour the apples in the barrel by saying that 3 to 1 is good for all 'modern' conditions.
If Mirelle was anchored with her current gear at the same time and the same place as Mirabella V with a 3 to 1 scope would Mirelle have dragged in the same way as Mirabella V dragged onto the rocks?
The answer is YES. The dreadful downside is that Mirelle would have broken up on the rocks and all for the sake of too small a scope for the combined conditions which were not 'modern' but real conditions.
Have you read Knox's treatises on practical anchoring? (Porridge for tea?)
Mirelle
N/A
Downright bad seamanship and irresponsibility!
Thank you for the lesson! /forums/images/graemlins/wink.gif
Yes, I mean grossly overcrowded anchorages. It is bad seamanship and irresponsible to veer more cable than you need. There are any number of cases at law on this point.
Yes, I have dragged, twice, on a 3:1 scope. Once was in a fjord where we dragged off the terminal moraine of a glacier into deep water, the second time (history repeats itself as farce!) was at Stone Point in Walton Backwaters, Bank Holiday Saturday, year before last - cause just the same - I thought I had got the hook down clear of the deep hole, but I had missed, and we dragged off the edge and into the hole. In both cases, a longer scope would have made no difference except in the time needed to recover the anchor and get the boat under control!
The thing which starts an anchor dragging is the snatching load transmitted down a taut chain or warp. The angle at which the warp lies to the anchor is of lesser importance so long as it is along the bottom and not taut.
Every year someone, often some dozens of people, anchor in shoal water with a 10:1 scope and a blow comes on. Several of them skid down to leeward and wonder "what on earth can have happened - surely they had plenty of scope out?"
The answer is that in shallow water the chain cannot form a good catenary; it gets pulled out straight along the bottom and one good gust snatches the anchor out.
A long scope is no magic solution.
Conversely, when did you last see a Thames barge, or a smack, veer a 10:1 scope when anchoring?
To veer more cable than you need, in a crowded roadstead, is a recipe for lost sleep and hard words in the early hours.
You say you commonly veer 4-5 times the depth at HW so as to allow yourself room to swing, but how can the boats that arrive after you and anchor uptide of you know where your anchor is?
Thank you for the lesson! /forums/images/graemlins/wink.gif
Yes, I mean grossly overcrowded anchorages. It is bad seamanship and irresponsible to veer more cable than you need. There are any number of cases at law on this point.
Yes, I have dragged, twice, on a 3:1 scope. Once was in a fjord where we dragged off the terminal moraine of a glacier into deep water, the second time (history repeats itself as farce!) was at Stone Point in Walton Backwaters, Bank Holiday Saturday, year before last - cause just the same - I thought I had got the hook down clear of the deep hole, but I had missed, and we dragged off the edge and into the hole. In both cases, a longer scope would have made no difference except in the time needed to recover the anchor and get the boat under control!
The thing which starts an anchor dragging is the snatching load transmitted down a taut chain or warp. The angle at which the warp lies to the anchor is of lesser importance so long as it is along the bottom and not taut.
Every year someone, often some dozens of people, anchor in shoal water with a 10:1 scope and a blow comes on. Several of them skid down to leeward and wonder "what on earth can have happened - surely they had plenty of scope out?"
The answer is that in shallow water the chain cannot form a good catenary; it gets pulled out straight along the bottom and one good gust snatches the anchor out.
A long scope is no magic solution.
Conversely, when did you last see a Thames barge, or a smack, veer a 10:1 scope when anchoring?
To veer more cable than you need, in a crowded roadstead, is a recipe for lost sleep and hard words in the early hours.
You say you commonly veer 4-5 times the depth at HW so as to allow yourself room to swing, but how can the boats that arrive after you and anchor uptide of you know where your anchor is?
webcraft
Well-known member
Re: Downright bad seamanship and irresponsibility!
[ QUOTE ]
You say you commonly veer 4-5 times the depth at HW so as to allow yourself room to swing, but how can the boats that arrive after you and anchor uptide of you know where your anchor is?
[/ QUOTE ]
I didn't say it was to allow room to swing . . . it is because I believe 3-1 scope to be a bare minimum, and prefer to put out more.
If I am anchored in 7m at HW with a 4m fall and I put out 30m then my swinging circle will be approx. 50m - I consider that reasonable. I certainly don't anchor closer to other boats than that. I think to assume that everyone has 3-1 scope out is somewhat naive. Many boats have no idea how much is out . . .
I particularly disagree with your contention that the angle of the rode to the shank is not important. Testing of anchors has definitely shown otherwise. As I (and many others) understand it catenary is what keeps the pull horizontal in calmer conditions, but when the chain is taut scope is the only thing that governs the angle and hence the tendency of the anchor to pull out. Makes perfect sense to me, and if you are anchoring with gear so heavy that there is always catenary no matter what the conditions then all I can say is that most modern boats couldn't even carry the stuff, let alone deploy it.
Mirelle, I am surprised that what you have to say goes against all current thinking on the subject . . . doesn't necessarily mean you are wrong, but I will continue to enjoy a good night's sleep with my current practice.
I do think however that advice like this from old salts can be misleading to newbies, and would encourage anyone nervous about anchoring and reading this thread to read as much as possible, go out with different skippers and in the end make up their own minds as to what will work best for their boat.
Above all I would avoid grossly overcrowded anchorages. IMHO anchoring in such places in the first place is in itself bad seamanship, and usually not much fun either.
- Nick
[ QUOTE ]
You say you commonly veer 4-5 times the depth at HW so as to allow yourself room to swing, but how can the boats that arrive after you and anchor uptide of you know where your anchor is?
[/ QUOTE ]
I didn't say it was to allow room to swing . . . it is because I believe 3-1 scope to be a bare minimum, and prefer to put out more.
If I am anchored in 7m at HW with a 4m fall and I put out 30m then my swinging circle will be approx. 50m - I consider that reasonable. I certainly don't anchor closer to other boats than that. I think to assume that everyone has 3-1 scope out is somewhat naive. Many boats have no idea how much is out . . .
I particularly disagree with your contention that the angle of the rode to the shank is not important. Testing of anchors has definitely shown otherwise. As I (and many others) understand it catenary is what keeps the pull horizontal in calmer conditions, but when the chain is taut scope is the only thing that governs the angle and hence the tendency of the anchor to pull out. Makes perfect sense to me, and if you are anchoring with gear so heavy that there is always catenary no matter what the conditions then all I can say is that most modern boats couldn't even carry the stuff, let alone deploy it.
Mirelle, I am surprised that what you have to say goes against all current thinking on the subject . . . doesn't necessarily mean you are wrong, but I will continue to enjoy a good night's sleep with my current practice.
I do think however that advice like this from old salts can be misleading to newbies, and would encourage anyone nervous about anchoring and reading this thread to read as much as possible, go out with different skippers and in the end make up their own minds as to what will work best for their boat.
Above all I would avoid grossly overcrowded anchorages. IMHO anchoring in such places in the first place is in itself bad seamanship, and usually not much fun either.
- Nick
snowleopard
Active member
Re: Downright bad seamanship and irresponsibility!
[ QUOTE ]
Above all I would avoid grossly overcrowded anchorages. IMHO anchoring in such places in the first place is in itself bad seamanship, and usually not much fun either.
[/ QUOTE ]
if only life were that simple - or do you advocate sticking to marinas? sometimes there is no choice but to squeeze into a crowded anchorage. to cite a few examples - funchal in madeira has only one possible anchorage and it's always full, with a wind that boxes the compass twice a day. the alternative is to sail past the island. at fort de france in martinique, there is again only one anchorage within reach of the customs house and at la coruna the anchorage is restricted and 18m deep.
in places like that you have no choice where to go, nor the room to swing on 5:1 scope.
in an ideal world we would all use anchors and chain twice the recommended size and put out all our chain every time. in the real world we must compromise. that's not bad seamanship.
[ QUOTE ]
Above all I would avoid grossly overcrowded anchorages. IMHO anchoring in such places in the first place is in itself bad seamanship, and usually not much fun either.
[/ QUOTE ]
if only life were that simple - or do you advocate sticking to marinas? sometimes there is no choice but to squeeze into a crowded anchorage. to cite a few examples - funchal in madeira has only one possible anchorage and it's always full, with a wind that boxes the compass twice a day. the alternative is to sail past the island. at fort de france in martinique, there is again only one anchorage within reach of the customs house and at la coruna the anchorage is restricted and 18m deep.
in places like that you have no choice where to go, nor the room to swing on 5:1 scope.
in an ideal world we would all use anchors and chain twice the recommended size and put out all our chain every time. in the real world we must compromise. that's not bad seamanship.
G
Guest
Guest
Re: Disagree. Completely.
'Modern conditions' do not permit the carrying of gear that is safe to anchor with at 3:1. Most boats are lighter than Mirelle. When I bought my Contessa, she had heavier anchoring gear than is typically found on boats of her size - 20m of chain and 30m of rope, with a 25lb CQR. One of the first things I did was to replace this to make it heavier - with 30m of chain and 40m of (thicker) rope. This I would say was a heavy specification for boats of her type in the real world, and fills the anchor locker to the brim (the anchor has been mounted externally). I suspect the reality is that very very few Contessas carry heavier/longer chain/rope, and even fewer AWBs. For good reason: it is in 99% of situations perfectly adequate.
BTW the original chain/rope was kept as a reserve for shackling on the end of the main anchor rode for use in especially deep water, so the rode could increase to 50m chain and 70m rope.
The effect on trim and performance of the boat was noticeable, even though the Contessa is not particularly lightweight for her size - I think that more lightweight modern boats would be even more affected.
I suspect that you would consider this weight of anchor and chain to be on the light side. But until everyone buys a heavy boat, then this is what 'modern conditions' are. I don't feel the need to change my boat just so that I can change my anchor scope from 4:1 to 3:1.
The combination works superbly at a 4:1 scope. At a 3:1 scope, even if well dug in it is a fact that a strong enough wind it WILL rip it out of the ground. My test is whether the anchor will hold at almost full revs astern, which approximates to the force exerted by a 30 knot wind (in a 30 knot wind my engine can just hold the stern to the wind, but won't make any progress to windward). Even if well dug in, this will usually be enough to break the anchor out of the ground.
In 'modern conditions' meaning crowded anchorages, it is sometimes necessary to shorten to 3:1 and keep a good eye out for dragging at high tide. It shouldn't drag at 3:1 unless the wind gets up, or shearing occurs. However, I am fortunate in that the great majority of anchorages that I go to are deserted, so swinging room is not normally a problem, so I rarely have to do this. It would be bad seamanship for me to shorten to 3:1 if there were no reasonable likelihood of others anchoring close.
If I am in an anchorage with others, I use my discretion, depending on all the circumstances, whether to shorten. This includes the weather condition, the underwater and above water profile of the boat(s) around me etc. I also inform my neighbours what scope I have down, and ask what they have down, so as to assess whether there is a risk of a bump.
'Modern conditions' do not permit the carrying of gear that is safe to anchor with at 3:1. Most boats are lighter than Mirelle. When I bought my Contessa, she had heavier anchoring gear than is typically found on boats of her size - 20m of chain and 30m of rope, with a 25lb CQR. One of the first things I did was to replace this to make it heavier - with 30m of chain and 40m of (thicker) rope. This I would say was a heavy specification for boats of her type in the real world, and fills the anchor locker to the brim (the anchor has been mounted externally). I suspect the reality is that very very few Contessas carry heavier/longer chain/rope, and even fewer AWBs. For good reason: it is in 99% of situations perfectly adequate.
BTW the original chain/rope was kept as a reserve for shackling on the end of the main anchor rode for use in especially deep water, so the rode could increase to 50m chain and 70m rope.
The effect on trim and performance of the boat was noticeable, even though the Contessa is not particularly lightweight for her size - I think that more lightweight modern boats would be even more affected.
I suspect that you would consider this weight of anchor and chain to be on the light side. But until everyone buys a heavy boat, then this is what 'modern conditions' are. I don't feel the need to change my boat just so that I can change my anchor scope from 4:1 to 3:1.
The combination works superbly at a 4:1 scope. At a 3:1 scope, even if well dug in it is a fact that a strong enough wind it WILL rip it out of the ground. My test is whether the anchor will hold at almost full revs astern, which approximates to the force exerted by a 30 knot wind (in a 30 knot wind my engine can just hold the stern to the wind, but won't make any progress to windward). Even if well dug in, this will usually be enough to break the anchor out of the ground.
In 'modern conditions' meaning crowded anchorages, it is sometimes necessary to shorten to 3:1 and keep a good eye out for dragging at high tide. It shouldn't drag at 3:1 unless the wind gets up, or shearing occurs. However, I am fortunate in that the great majority of anchorages that I go to are deserted, so swinging room is not normally a problem, so I rarely have to do this. It would be bad seamanship for me to shorten to 3:1 if there were no reasonable likelihood of others anchoring close.
If I am in an anchorage with others, I use my discretion, depending on all the circumstances, whether to shorten. This includes the weather condition, the underwater and above water profile of the boat(s) around me etc. I also inform my neighbours what scope I have down, and ask what they have down, so as to assess whether there is a risk of a bump.
PeterStone
New member
You have Eric Hiscock on your side....
According to Eric Hiscock, and I think most people would agree he knew a bit more about the subject than most, 3:1 paid out at high water is ample and less may be paid out in deep water.
I quote here from 'Cruising under Sail'
"Insufficient scope of cable is the most common cause of anchors dragging, and three times the depth of water at high water should be paid out. In depths exceeding 10 fathoms, however, the proportion of chain may be less."
Twice around the world in Wanderer III and again in Wanderer IV and numerous other ocean voyages must count for something surely?
According to Eric Hiscock, and I think most people would agree he knew a bit more about the subject than most, 3:1 paid out at high water is ample and less may be paid out in deep water.
I quote here from 'Cruising under Sail'
"Insufficient scope of cable is the most common cause of anchors dragging, and three times the depth of water at high water should be paid out. In depths exceeding 10 fathoms, however, the proportion of chain may be less."
Twice around the world in Wanderer III and again in Wanderer IV and numerous other ocean voyages must count for something surely?
Talbot
Active member
Re: Downright bad seamanship and irresponsibility!
IMHO the older style (= heavier/long keel) boats sit much easier at anchor than a the new AWBs, and also tend to have appropriate tackle for the job. New AWBs tend to be supplied with the bare minimum recommended tackle (which I reckon is at least one size too small), and thus need to use more than 3:1 for any sane approach to anchoring. When you add in multihulls which need to minimise on weight at the bow, thus relying on a shortish length of chain, and then rope which necessitates better than 4:1 (depending on length of chain and depth of water), and also factor that in a strong wind, the multihull may be more affected by the wind rather than the tide, you start to recognise the existing problem.
I started this thread not to get into a p*ssing contest about what scope to use, /forums/images/graemlins/shocked.gif cause there are all sorts of reasons for different scopes (some of which I have added above) but rather to see whether this problem is even considered by those happy to dangle from the end of a hook in the bottom of the ocean. /forums/images/graemlins/grin.gif
IMHO the older style (= heavier/long keel) boats sit much easier at anchor than a the new AWBs, and also tend to have appropriate tackle for the job. New AWBs tend to be supplied with the bare minimum recommended tackle (which I reckon is at least one size too small), and thus need to use more than 3:1 for any sane approach to anchoring. When you add in multihulls which need to minimise on weight at the bow, thus relying on a shortish length of chain, and then rope which necessitates better than 4:1 (depending on length of chain and depth of water), and also factor that in a strong wind, the multihull may be more affected by the wind rather than the tide, you start to recognise the existing problem.
I started this thread not to get into a p*ssing contest about what scope to use, /forums/images/graemlins/shocked.gif cause there are all sorts of reasons for different scopes (some of which I have added above) but rather to see whether this problem is even considered by those happy to dangle from the end of a hook in the bottom of the ocean. /forums/images/graemlins/grin.gif
G
Guest
Guest
Re: You have Eric Hiscock on your side....
I think he is talking about heavy-ish displacement boats and an all-chain scope, I guess fairly thick chain (don't have time to flick through the book at this moment to check), presumably something like Mirelle's set up. I doubt that many would argue that Mirelle's anchoring set-up is inadequate, I would just say that it is not appropriate for most 'modern' boats. Incidentally it's clear that Hiscock refers to an all-chain rode, as he refers to (from your quote) in depths over 10m the proportion of CHAIN being less.
Even with an all-chain scope, the attitude of the Mirabella V report was that: "Yachtsmen traditionally pay out chain on a 3:1 scope rule… AS A MINIMUM [my emphasis]. Normally the scope would be increased to 4:1 for longer stays and 5:1 for greater confidence in medium/heavy weather." They are of course talking about standard practice among yachtsmen in more 'normally' sized yachts.
The 98%(?) of Yachtsmen with rope and chain combinations need to be even more cautious. Mirabella V report shows the official view. Certainly your insurance company is unlikely to be happy if you scrunch having dragged on a 3:1 scope in anything but the calmest weather.
As another poster said, it would be unfortunate if others, perhaps inexperienced in anchoring, took this to mean that a 3:1 scope is an adequate standard. In an anchorage with other boats I would rather that they put down some more and swung a bit more.
In fact, the extra swinging room with 4:1 is likely to be negligible partly because normally the chain will not be stretched across the seabed, so there will be little difference in swinging room. The exception is in very strong winds or tides. But even then, at 10 m anchoring depth, the difference between 3:1 and 4:1 swinging radius even with the chain well stretched out with is only about 7 or 8m radius around the anchor, typically barely more than half a boat length. But strong winds are precisely the circumstances when you need more scope, and everyone will be swinging in the same direction anyway, so it doesn't matter. The exception is strong wind against strong tide, which is a tricky situation when boats may veer all over the place, but a short scope is definitely not the answer in those conditions.
I think he is talking about heavy-ish displacement boats and an all-chain scope, I guess fairly thick chain (don't have time to flick through the book at this moment to check), presumably something like Mirelle's set up. I doubt that many would argue that Mirelle's anchoring set-up is inadequate, I would just say that it is not appropriate for most 'modern' boats. Incidentally it's clear that Hiscock refers to an all-chain rode, as he refers to (from your quote) in depths over 10m the proportion of CHAIN being less.
Even with an all-chain scope, the attitude of the Mirabella V report was that: "Yachtsmen traditionally pay out chain on a 3:1 scope rule… AS A MINIMUM [my emphasis]. Normally the scope would be increased to 4:1 for longer stays and 5:1 for greater confidence in medium/heavy weather." They are of course talking about standard practice among yachtsmen in more 'normally' sized yachts.
The 98%(?) of Yachtsmen with rope and chain combinations need to be even more cautious. Mirabella V report shows the official view. Certainly your insurance company is unlikely to be happy if you scrunch having dragged on a 3:1 scope in anything but the calmest weather.
As another poster said, it would be unfortunate if others, perhaps inexperienced in anchoring, took this to mean that a 3:1 scope is an adequate standard. In an anchorage with other boats I would rather that they put down some more and swung a bit more.
In fact, the extra swinging room with 4:1 is likely to be negligible partly because normally the chain will not be stretched across the seabed, so there will be little difference in swinging room. The exception is in very strong winds or tides. But even then, at 10 m anchoring depth, the difference between 3:1 and 4:1 swinging radius even with the chain well stretched out with is only about 7 or 8m radius around the anchor, typically barely more than half a boat length. But strong winds are precisely the circumstances when you need more scope, and everyone will be swinging in the same direction anyway, so it doesn't matter. The exception is strong wind against strong tide, which is a tricky situation when boats may veer all over the place, but a short scope is definitely not the answer in those conditions.
NigeCh
New member
Can\'t work out whether you\'re getting at me or ......
3 to 1 is just plain stupid. 4 to 1 will work for Mirelle in anything less than 20 m OA vertically. (Or more for that matte raccordiing tto Mirelle's posted numbers.)
Were I an insurer and the punter said that (like Mirabella) that I've deployed 65 metres in the depth as reported in the report then I say quite simply "On yer bike. Sunhine"
What you've got to work out is that MV isn't a yacht but an oversized toytown ferry that has no relevence to anything that just happens to be cutter rigged.
Anchoring Mirabella V is always going to be an art as both her anchors are a) undersized and b) not suitable for med ttype bopttoms.
On the other hand there is always Mirelle demonstrating that the exception proves the rule.
Anchoring isn't simple. Scope varies according tto bottoms and average expected wind speed creating the newtonian barrier which equates to windage + hull friction is less than the combined load to raise the chain more than the critical angel for a 100+++ set anchor. (ETC)
3 to 1 is just plain stupid. 4 to 1 will work for Mirelle in anything less than 20 m OA vertically. (Or more for that matte raccordiing tto Mirelle's posted numbers.)
Were I an insurer and the punter said that (like Mirabella) that I've deployed 65 metres in the depth as reported in the report then I say quite simply "On yer bike. Sunhine"
What you've got to work out is that MV isn't a yacht but an oversized toytown ferry that has no relevence to anything that just happens to be cutter rigged.
Anchoring Mirabella V is always going to be an art as both her anchors are a) undersized and b) not suitable for med ttype bopttoms.
On the other hand there is always Mirelle demonstrating that the exception proves the rule.
Anchoring isn't simple. Scope varies according tto bottoms and average expected wind speed creating the newtonian barrier which equates to windage + hull friction is less than the combined load to raise the chain more than the critical angel for a 100+++ set anchor. (ETC)
machurley22
New member
Re: You have Eric Hiscock on your side....
[ QUOTE ]
I quote here from 'Cruising under Sail'
"Insufficient scope of cable is the most common cause of anchors dragging, and three times the depth of water at high water should be paid out. In depths exceeding 10 fathoms, however, the proportion of chain may be less."
[/ QUOTE ]
This is not a quote.
My copy of Cruising under sail says:
"Insufficient scope of cable is the most common cause of anchors dragging; <font color="blue"> when using chain </font> three times the depth of water at high water should be veered, <font color="blue">and more in strong winds or when there is a sea running."</font>
Dave
[ QUOTE ]
I quote here from 'Cruising under Sail'
"Insufficient scope of cable is the most common cause of anchors dragging, and three times the depth of water at high water should be paid out. In depths exceeding 10 fathoms, however, the proportion of chain may be less."
[/ QUOTE ]
This is not a quote.
My copy of Cruising under sail says:
"Insufficient scope of cable is the most common cause of anchors dragging; <font color="blue"> when using chain </font> three times the depth of water at high water should be veered, <font color="blue">and more in strong winds or when there is a sea running."</font>
Dave
mirabriani
New member
Re: Downright bad seamanship and irresponsibility!
May I broaden the discussion? because this could easily be the result.
Suppose we have a situation where boat "A" say, on passage and needing a long lunch stop drops the anchor on minimal scope, has a meal and a kip.
Along comes boat "B" having heard the latest weather forecast, anchors on a much longer scope near to boat "A"
Crew of boat "A" wake up to a dragging anchor, needs lo lengthen scope and complains to boat "B" "You must move, you have given me a foul berth"
Boat "B" replies "You have anchored poorly, you must move, not I"
Who do you think should move?
Regards Briani
May I broaden the discussion? because this could easily be the result.
Suppose we have a situation where boat "A" say, on passage and needing a long lunch stop drops the anchor on minimal scope, has a meal and a kip.
Along comes boat "B" having heard the latest weather forecast, anchors on a much longer scope near to boat "A"
Crew of boat "A" wake up to a dragging anchor, needs lo lengthen scope and complains to boat "B" "You must move, you have given me a foul berth"
Boat "B" replies "You have anchored poorly, you must move, not I"
Who do you think should move?
Regards Briani
PeterStone
New member
Re: You have Eric Hiscock on your side....
It most certainly is a quote - I have no reason to mislead.
Ref: Page 176, "Cruising under Sail" second edition - 1972.
However - I'm a bit of a belt and braces man myself - and I certainly deploy extra scope in stronger wind myself - though I'm not sure if this is more for peace of mind than to increase the security of the boat!
It most certainly is a quote - I have no reason to mislead.
Ref: Page 176, "Cruising under Sail" second edition - 1972.
However - I'm a bit of a belt and braces man myself - and I certainly deploy extra scope in stronger wind myself - though I'm not sure if this is more for peace of mind than to increase the security of the boat!
jenku
New member
Re: Downright bad seamanship and irresponsibility!
The one with the shorter scope should move. It's easier for him to weigh and it's him who wants to make a change in status quo.
The one with the shorter scope should move. It's easier for him to weigh and it's him who wants to make a change in status quo.
Ships_Cat
New member
Re: Disagree. Completely.
Seems to be an interesting tussle going on here.
On one hand you have a couple of posters who quote good anchoring experiences for themselves and relate judgements developed from their own knowledge.
Whereas on the other hand you have a number of posters who apparantly have bad or lacking in confidence anchoring experiences and who seemingly can only relate judgements from the knowledge of others.
Furthermore, as far as I am aware, those having good anchoring experiences and relating judgements developed from their own knowledge actually work at a professional level in the marine industry. Whereas, as far as I know, those relating judgements quoting from the knowledge of others do not - perhaps they could clarify if this is so or not.
Doesn't this sound like a case of those of limited knowledge trying to cry down those of greater knowledge?
John
Seems to be an interesting tussle going on here.
On one hand you have a couple of posters who quote good anchoring experiences for themselves and relate judgements developed from their own knowledge.
Whereas on the other hand you have a number of posters who apparantly have bad or lacking in confidence anchoring experiences and who seemingly can only relate judgements from the knowledge of others.
Furthermore, as far as I am aware, those having good anchoring experiences and relating judgements developed from their own knowledge actually work at a professional level in the marine industry. Whereas, as far as I know, those relating judgements quoting from the knowledge of others do not - perhaps they could clarify if this is so or not.
Doesn't this sound like a case of those of limited knowledge trying to cry down those of greater knowledge?
John
PeterStone
New member
Re: You have Eric Hiscock on your side....
<I think he is talking about heavy-ish displacement boats and an all-chain scope, I guess fairly thick chain>
Again I quote from one of his books - this time 'Voyaging Under Sail'
"Wanderer III carried only 2 anchors during her voyages; each was of the plough type (genuine CQR) and weighed 35lb. She had 45 fathoms of 5/16" tested, short link chain; 30 fathoms of this was shackled to the port anchor; the remaining 15 fathoms, a separate length, was held in reserve either for increasing the scope on the port anchor when the anchorage was a deep one, or for use with the starboard anchor."
"She brought up in a great many anchorages and on a variety of bottoms, but only on a few occasions did she drag."
Hiscock's ground tackle, carried on Wanderer III, a considerably heavier boat than my own though of similar size, is identical to mine. I don't think you could describe his chain as being comparatively heavy, or his anchor being oversized.
He sailed a total of 110,000 miles on Wanderer III - rather more miles and experience than most I respectfully suggest, and so I wouldn't be quite so quick in dismissing the view that 3:1 scope is adequate.
<I think he is talking about heavy-ish displacement boats and an all-chain scope, I guess fairly thick chain>
Again I quote from one of his books - this time 'Voyaging Under Sail'
"Wanderer III carried only 2 anchors during her voyages; each was of the plough type (genuine CQR) and weighed 35lb. She had 45 fathoms of 5/16" tested, short link chain; 30 fathoms of this was shackled to the port anchor; the remaining 15 fathoms, a separate length, was held in reserve either for increasing the scope on the port anchor when the anchorage was a deep one, or for use with the starboard anchor."
"She brought up in a great many anchorages and on a variety of bottoms, but only on a few occasions did she drag."
Hiscock's ground tackle, carried on Wanderer III, a considerably heavier boat than my own though of similar size, is identical to mine. I don't think you could describe his chain as being comparatively heavy, or his anchor being oversized.
He sailed a total of 110,000 miles on Wanderer III - rather more miles and experience than most I respectfully suggest, and so I wouldn't be quite so quick in dismissing the view that 3:1 scope is adequate.
machurley22
New member
I beg your pardon Peter
I didn't mean to imply that it was your intention to mislead. I thought you'd paraphrased a bit carelessly and I didn't consider that you might have had an older version. My copy is the third edition - 1981.
Dave
I didn't mean to imply that it was your intention to mislead. I thought you'd paraphrased a bit carelessly and I didn't consider that you might have had an older version. My copy is the third edition - 1981.
Dave
PeterStone
New member
Re: Disagree. Completely.
<Whereas on the other hand you have a number of posters who apparantly have bad or lacking in confidence anchoring experiences and who seemingly can only relate judgements from the knowledge of others.>
Rather inflammatory don't you think?
Referring to higher authority doesn't mean you speak with no authority.
<Whereas on the other hand you have a number of posters who apparantly have bad or lacking in confidence anchoring experiences and who seemingly can only relate judgements from the knowledge of others.>
Rather inflammatory don't you think?
Referring to higher authority doesn't mean you speak with no authority.
Other threads that may be of interest
