36ft sailboat, anchoring not going well

[Irish Rover]

Of course. It's not about normal situations, it’s about the rare events. It’s the rare events that cause disasters, like plane crashes for example. That’s what a better design, a heavier, bigger surface area anchor will give you additional protection from. Plus, less hassle as they set far quicker. Very nice, but not necessary I admit.

No. The thread is exactly about normal situations - a relatively inexperience skipper struggling with his everyday anchoring. He's not asking for advice about "plane crashes". Let's keep it simple.

 

[stu9000]

I bought a Delta copy for my 35 footer last year as I was going to the Channel Islands, which is rockier than the East coast. I hated it. Maybe real Deltas as better but it gave me a number of sleepless nights and I've gone back to the old Bruce . In terms of how u can be helped here and now... your technique seems fine. Maybe daisy chain another anchor?

 

[Zing]

No. The thread is exactly about normal situations - a relatively inexperience skipper struggling with his everyday anchoring. He's not asking for advice about "plane crashes". Let's keep it simple.

The thread has drifted. You clearly didn’t notice, but the last part of my post does address it actually.

 

[Refueler]

I hear this often ... get a bigger anchor ... UGH !!

An anchor needs to not only have weight - but to 'work' with the boat / rode its trying to hold. Going too big can 1. be a real pain to manhandle, 2. fail to set due to boat / rode failing to exert enough to set it ... you think I'm wrong on that ? Actually it happens.

I am an advocate for biggest in the range for the boat ... until you get to a small pocket size boat - then the suggested anchors are too light and basically a joke .. then you need to be oversize so anchor has enough of its own weight / working to do its job.

 

[vyv_cox]

Of course. It's not about normal situations, it’s about the rare events. It’s the rare events that cause disasters, like plane crashes for example. That’s what a better design, a heavier, bigger surface area anchor will give you additional protection from. Plus, less hassle as they set far quicker. Very nice, but not necessary I admit.

There is absolutely no evidence that an anchor bigger or heavier holds better than one of the recommended size. Indeed, there is quite a bit of evidence to show the contrary. My Rocna, Delta and Fortress are all of the recommended size. We have sat out innumerable gales and worse, 50+ knots on one occasion. We have never dragged once the anchors have set.

You might like to read Oversize anchors – necessary?

 

[Zing]

I hear this often ... get a bigger anchor ... UGH !!

An anchor needs to not only have weight - but to 'work' with the boat / rode its trying to hold. Going too big can 1. be a real pain to manhandle, 2. fail to set due to boat / rode failing to exert enough to set it ... you think I'm wrong on that ? Actually it happens.

I am an advocate for biggest in the range for the boat ... until you get to a small pocket size boat - then the suggested anchors are too light and basically a joke .. then you need to be oversize so anchor has enough of its own weight / working to do its job.

I agree, I think you want just the biggest you can get that doesn't cause you big problems.

 

[Zing]

There is absolutely no evidence that an anchor bigger or heavier holds better than one of the recommended size. Indeed, there is quite a bit of evidence to show the contrary. My Rocna, Delta and Fortress are all of the recommended size. We have sat out innumerable gales and worse, 50+ knots on one occasion. We have never dragged once the anchors have set.

You might like to read Oversize anchors – necessary?

Anchor makers do specifically say if you want better holding under higher loads then go up a size. That may not be the evidence you want, but it implies the load capacity does go up if you go above the recommended size.

I don't see anything in your piece about tip pressure. Modern anchors have much higher tip pressure and so set quicker and easier. Bigger anchors have even more tip pressure as pressure goes up substantially with weight and therefore set even quicker and better. Higher tip pressure also means they can cut through sea grass and seaweed more easily and set in some instances where light ones will not at all.

Oversize anchors are also useful when in extreme conditions. Like a bad Melemi such as you might get in the Eastern Med, or a Medicane, Where their ultimate greater holding power may be useful. Similarly oversized anchors give correspondingly better holding in poor substrates, mud or loose sand/coral/stones.

There is no downside, so long as you don't overdo the oversizing, but only upsides.

 

[vyv_cox]

Anchor makers do specifically say if you want better holding under higher loads then go up a size. That may not be the evidence you want, but it implies the load capacity does go up if you go above the recommended size.

I don't see anything in your piece about tip pressure. Modern anchors have much higher tip pressure and so set quicker and easier. Bigger anchors have even more tip pressure as pressure goes up substantially with weight and therefore set even quicker and better. Higher tip pressure also means they can cut through sea grass and seaweed more easily and set in some instances where light ones will not at all.

Oversize anchors are also useful when in extreme conditions. Like a bad Melemi such as you might get in the Eastern Med, or a Medicane, Where their ultimate greater holding power may be useful. Similarly oversized anchors give correspondingly better holding in poor substrates, mud or loose sand/coral/stones.

There is no downside, so long as you don't overdo the oversizing, but only upsides.

We have spent the past 13 years in the Eastern Med, on the vast majority of nights at anchor. Stern-to in ports the loads are probably higher than at free anchor, as in many cases the wind is on the beam, increasing the area exposed to wind (and not including a neighbour boat lying on you because he doesn't know how to anchor).

The reality is that even under the strongest of conditions it is extremely rare for our anchors to bury completely, so how does a bigger anchor contribute when half of it is not buried?

Weight is not an issue, anchors set by design. We have sat out a full gale on our 4 kg Fortress with only 3:1 scope of Anchorplait due to a marking misunderstanding. Viking anchors are considerably lighter than most equivalent steel anchors but apparently hold exceptionally well.

 

[Tranona]

Anchor makers do specifically say if you want better holding under higher loads then go up a size. That may not be the evidence you want, but it implies the load capacity does go up if you go above the recommended size.

I don't see anything in your piece about tip pressure. Modern anchors have much higher tip pressure and so set quicker and easier. Bigger anchors have even more tip pressure as pressure goes up substantially with weight and therefore set even quicker and better. Higher tip pressure also means they can cut through sea grass and seaweed more easily and set in some instances where light ones will not at all.

Oversize anchors are also useful when in extreme conditions. Like a bad Melemi such as you might get in the Eastern Med, or a Medicane, Where their ultimate greater holding power may be useful. Similarly oversized anchors give correspondingly better holding in poor substrates, mud or loose sand/coral/stones.

There is no downside, so long as you don't overdo the oversizing, but only upsides.

The recommendations are actually couched in terms of boats on the margins or different from the norm, not in terms of better performance per se. The obvious ones are multihulls where the windage is substantially higher than monos of the same length or cruisers kitted out for long term cruising with radar/solar arches, biminis and so on that up their weight and windage compared with standard boats of the same design.

Do you have any documented evidence of independent tests that support the other claims you make? Many people make similar claims but I have yet to see any real evidence. For example i have never seen any tester of anchors citing tip pressure as being important, let alone measuring the impact on setting from the increase of say a 20kg over the recommended 15kg. If you are correct that tip pressure is important and that NG anchors (all?) have higher tip pressures then swapping the Delta for the same size Epsilon is a good recommendation. Perhaps, however, you recognise this is all speculation given the number of times you have used the word "maybe".

The thread has drifted as some want to take it into areas that are different from the OP's question. There is plenty to discuss and comment upon in the original question as it a real world issue for those who use that type of boat in that part of the world - and there are many - without going too far off the basics of choice of gear and technique in "normal" situations.

 

[Neeves]

Maybe daisy chain another anchor?

This will really confuse the OP and will probably be a disaster.

Tandem Anchoring - Practical Sailor

Jonathan

 

[noelex]

Anchor makers do specifically say if you want better holding under higher loads then go up a size. That may not be the evidence you want, but it implies the load capacity does go up if you go above the recommended size.

Absolutely. The relationship between anchor size and holding ability is well established.

The extra holding power of a larger anchor (compared to a smaller anchor of identical design) is commonly thought to be only of benefit in very severe conditions, but this extra holding power applies to all substrates (with the exception of rock) and at all scopes.

This extra holding power can usefully be utilised to safely anchor in poorer substrates (for example in thicker weed) or at a shorter scope than would prudent with an identical, but smaller anchor.

This does not mean you can be reckless, but choosing an anchor (both the design and size) with the best performance opens up anchoring opportunities that would otherwise not be safe.

This is why I think it is sensible for the OP, or any cruising boat that plans on anchoring frequently to choose the largest anchor in the best design that they can comfortably manage.

 

[Neeves]

Absolutely.

This extra holding power of a larger anchor (compared to smaller anchor of identical design) is commonly thought to be only of benefit in very severe conditions, but this extra holding power applies to all substrates (with the exception of rock) and at all scopes.

This extra holding power can usefully be utilised to safely anchor in poorer substrates (for example thick weed) or at a shorter scope than would prudent with an identical, but smaller anchor.

This does not mean you can be reckless, but choosing an anchor (both the design and weight) with the best performance opens up anchoring opportunities that would otherwise not be safe.

This is why I think it is sensible for the OP, or any cruising boat that plans on anchoring frequently to choose the largest anchor they can comfortably manage in the best design.

A reason to use a Fishermans anchor in weed is because it has a small fluke that can penetrate the weed bed. How is a large anchor being set by a yacht that is too small for the anchor going to encourage their large anchor to wriggle into and through the seaweed and its mass of roots

The holding capacity of a, say, 15kg anchor is well beyond the tension likely to be developed by the windage of the yacht for which the 15kg anchor is recommended - what benefit is there to have a 1,000kg potential hold if the maximum tension is likely to be less than 1,000kg (and nearer 500kg)

If the yacht is on short scope the possibility of the development of veering increases geometrically and the snatch loads will increase similarly. If you want, or need, to have short scope you need to replace loss of catenary with a, longer, snubber - not a bigger anchor. I know which is cheaper, the longer snubber, and I know which offers the better anchoring experience, the longer snubber and which will not detract from the sailing ability of the yacht, the longer snubber.

As Tranona says this is developing drift well beyond the needs of the OP. I am quite happy to contribute to a thread covering some of the issues raised by both Zing and Noelex and I will support my statements with test data. Sadly I doubt Zing nor Noelex can substantiate their statements as these discussions are never supported by the 'bigger is better' parties with data.

Jonathan

 

[Tranona]

Absolutely. The relationship between anchor size and holding ability is well established.

The extra holding power of a larger anchor (compared to a smaller anchor of identical design) is commonly thought to be only of benefit in very severe conditions, but this extra holding power applies to all substrates (with the exception of rock) and at all scopes.

This extra holding power can usefully be utilised to safely anchor in poorer substrates (for example in thicker weed) or at a shorter scope than would prudent with an identical, but smaller anchor.

This does not mean you can be reckless, but choosing an anchor (both the design and size) with the best performance opens up anchoring opportunities that would otherwise not be safe.

This is why I think it is sensible for the OP, or any cruising boat that plans on anchoring frequently to choose the largest anchor in the best design that they can comfortably manage.

Once again, this is really not supported by any COMPARATIVE testing - that is side by side, same boat, same conditions, same seabed, different size anchors. Look at Vyv's article above which clearly shows that anchors rarely fully bury . Neeves points out that there is a limit to the load a boat can apply which is way less than the hold of the recommended anchor. A bigger (but not necessarily heavier) anchor holds at a higher load because it has greater area - but if that area does not bury you cannot exploit that extra holding power.

The whole point of NG anchors is to achieve the same level of performance with LIGHTER anchors, and all the tests show that this is achieved. Why then would anybody use an anchor that is larger and heavier than required? There is a huge margin of safety in chain and anchors when using the recommended sizes and the next size up is only considered when the boat in question is at the margins or has characteristics that move its potential loads up into the next category. This is often a matter of judgement based on an understanding of the forces involved.

 

[Irish Rover]

Come on, bigger is better advocates. You've been called out. Put your science up front where your bow rollers are, or drift off into the murky depths and keep your chain lockers bolted in future.

 

[Zing]

The recommendations are actually couched in terms of boats on the margins or different from the norm, not in terms of better performance per se. The obvious ones are multihulls where the windage is substantially higher than monos of the same length or cruisers kitted out for long term cruising with radar/solar arches, biminis and so on that up their weight and windage compared with standard boats of the same design.

Do you have any documented evidence of independent tests that support the other claims you make? Many people make similar claims but I have yet to see any real evidence. For example i have never seen any tester of anchors citing tip pressure as being important, let alone measuring the impact on setting from the increase of say a 20kg over the recommended 15kg. If you are correct that tip pressure is important and that NG anchors (all?) have higher tip pressures then swapping the Delta for the same size Epsilon is a good recommendation. Perhaps, however, you recognise this is all speculation given the number of times you have used the word "maybe".

The thread has drifted as some want to take it into areas that are different from the OP's question. There is plenty to discuss and comment upon in the original question as it a real world issue for those who use that type of boat in that part of the world - and there are many - without going too far off the basics of choice of gear and technique in "normal" situations.

No, the tables from suppliers such as Rocna and Mantus for example make it clear for stronger conditions you need a bigger one. That's not couching on the margins.

No, there is little indirect and actually no use of the word 'maybe' by me.

For documentary evidence see the end.

Plenty of yachts drag in 'normal' or benign locations and conditions for this to be an issue for everyone. What is more, everyone can potentially encounter extreme conditions, even on that one week August charter in the 'normally' benign Tyrrhenian or Ionian sea. I don't agree with your claim that it is unimportant to get a big and superior anchor.

A reason to use a Fishermans anchor in weed is because it has a small fluke that can penetrate the weed bed. How is a large anchor being set by a yacht that is too small for the anchor going to encourage their large anchor to wriggle into and through the seaweed and its mass of roots

The holding capacity of a, say, 15kg anchor is well beyond the tension likely to be developed by the windage of the yacht for which the 15kg anchor is recommended - what benefit is there to have a 1,000kg potential hold if the maximum tension is likely to be less than 1,000kg (and nearer 500kg)

If the yacht is on short scope the possibility of the development of veering increases geometrically and the snatch loads will increase similarly. If you want, or need, to have short scope you need to replace loss of catenary with a, longer, snubber - not a bigger anchor. I know which is cheaper, the longer snubber, and I know which offers the better anchoring experience, the longer snubber and which will not detract from the sailing ability of the yacht, the longer snubber.

As Tranona says this is developing drift well beyond the needs of the OP. I am quite happy to contribute to a thread covering some of the issues raised by both Zing and Noelex and I will support my statements with test data. Sadly I doubt Zing nor Noelex can substantiate their statements as these discussions are never supported by the 'bigger is better' parties with data.

Jonathan

Your argument is there is no point going bigger, because the yacht can't overload the smaller one relies on an assumption that is wrong, that the yacht is anchored in perfect ground, which can hold the full load of any anchor. Often the ground just isn't so and a bigger one will give better holding.

As for substantiation and peer reviewed research see the end.

Once again, this is really not supported by any COMPARATIVE testing - that is side by side, same boat, same conditions, same seabed, different size anchors. Look at Vyv's article above which clearly shows that anchors rarely fully bury . Neeves points out that there is a limit to the load a boat can apply which is way less than the hold of the recommended anchor. A bigger (but not necessarily heavier) anchor holds at a higher load because it has greater area - but if that area does not bury you cannot exploit that extra holding power.

The whole point of NG anchors is to achieve the same level of performance with LIGHTER anchors, and all the tests show that this is achieved. Why then would anybody use an anchor that is larger and heavier than required? There is a huge margin of safety in chain and anchors when using the recommended sizes and the next size up is only considered when the boat in question is at the margins or has characteristics that move its potential loads up into the next category. This is often a matter of judgement based on an understanding of the forces involved.

You don't need comparative testing to support my claims re tip pressure and area, but there is actually a lot of comparative testing on the web on differenty anchor designs in idential substrates if you wish to Google for it. Also see the end.

No, the whole point of NG anchors is not to enable lighter anchors. It is to do a better job. A better job is mainly to dig in easier and to drag less than the old rubbish (and a lot of it is rubbish Sorry).

Come on, bigger is better advocates. You've been called out. Put your science up front where your bow rollers are, or drift off into the murky depths and keep your chain lockers bolted in future.

As to science. A quick Google search leads to an article by our very Vyv above who wrote in Yachting Monthly about the superior tip pressure of NG anchors and gave some clear numbers for that. Vyv has undoubtedly access to scientific research for this.

Besides, this is like asking for proof the sun will rises every day. You put the Queen Mary II's anchor tip on your right toe and put my dinghy anchor tip on your left toe and you tell me which has greater tip pressure and which will dig in deeper.

Similarly as to the notion that larger anchors hold better in poor ground, that again a daft request. It's a fundamental calculation in civil engineering that a ground anchor or foundations or any structure or device increases its holding capacity with its area. It's the same with anchors and somethings you shouldn't be asking for proof for.

 

[vyv_cox]

No, the tables from suppliers such as Rocna and Mantus for example make it clear for stronger conditions you need a bigger one. That's not couching on the margins.

No, there is little indirect and actually no use of the word 'maybe' by me.

For documentary evidence see the end.

Plenty of yachts drag in 'normal' or benign locations and conditions for this to be an issue for everyone. What is more, everyone can potentially encounter extreme conditions, even on that one week August charter in the 'normally' benign Tyrrhenian or Ionian sea. I don't agree with your claim that it is unimportant to get a big and superior anchor.


Your argument is there is no point going bigger, because the yacht can't overload the smaller one relies on an assumption that is wrong, that the yacht is anchored in perfect ground, which can hold the full load of any anchor. Often the ground just isn't so and a bigger one will give better holding.

As for substantiation and peer reviewed research see the end.


You don't need comparative testing to support my claims re tip pressure and area, but there is actually a lot of comparative testing on the web on differenty anchor designs in idential substrates if you wish to Google for it. Also see the end.

No, the whole point of NG anchors is not to enable lighter anchors. It is to do a better job. A better job is mainly to dig in easier and to drag less than the old rubbish (and a lot of it is rubbish Sorry).



As to science. A quick Google search leads to an article by our very Vyv above who wrote in Yachting Monthly about the superior tip pressure of NG anchors and gave some clear numbers for that. Vyv has undoubtedly access to scientific research for this.

Besides, this is like asking for proof the sun will rises every day. You put the Queen Mary II's anchor tip on your right toe and put my dinghy anchor tip on your left toe and you tell me which has greater tip pressure and which will dig in deeper.

Similarly as to the notion that larger anchors hold better in poor ground, that again a daft request. It's a fundamental calculation in civil engineering that a ground anchor or foundations or any structure or device increases its holding capacity with its area. It's the same with anchors and somethings you shouldn't be asking for proof for.

If I remember correctly my article discussed the relative proportions of tip loading on a variety of anchors. This is not the same property as tip pressure. Tip loading is the property that causes an anchor to set rather than skid over the surface. Pressure requires the input of mass, which in your interpretation means that a light anchor will never set: clearly not true.

 

[Zing]

If I remember correctly my article discussed the relative proportions of tip loading on a variety of anchors. This is not the same property as tip pressure. Tip loading is the property that causes an anchor to set rather than skid over the surface. Pressure requires the input of mass, which in your interpretation means that a light anchor will never set: clearly not true.

Yes it does, but 40% of a big anchor weight of 1000kg is a tip pressure of 400kg. A lot more than my dinghy anchor. So why would that tip loading not be more and why would it not dig in more?

Of course pressure requires mass. It goes without saying.

It's about relative performance and tip pressure, goes up with both weight and superior design. That's my point.

 

[stu9000]

This will really confuse the OP and will probably be a disaster.

Tandem Anchoring - Practical Sailor

Jonathan

Hmm. Maybe. Not that complicated and he has a boat so im sure he can make decisions appropriate to his current situation.

I skimmed the article and accept the point that it'd better to have one appropriate anchor than be bodging solutions. But if he is out there now and not in a position to nip out and buy a new anchor , its worth a shot.

 

[Neeves]

So its a hard seabed and the anchor of the right size, say a Rocna or Spade will not penetrate the substrate. Lets get the bigger anchor out - Noelex and Zing says its the answer and if they say so they must be right

'So why does the bigger anchor not penetrate the hard substrate?'

Ah - maybe Noelex and Zing are all talk and no data

The US Navy answer to the hard substrate is 'sharpen the toe' - it is not 'a bigger anchor'.

I note that neither Zing nor Noelex are able to describe the mechanism that allows the bigger anchor to penetrate weed. The cows will come home - but they will not be able to describe the mechanism that miraculously allows the bigger anchor to penetrate the hard seabed that defeated the smaller anchor of the same design


All talk and no trousers. (or in typical 'anchor thread speak' unsubstantiated claims and no data'


We already have Noelex in denial over his Mantus M1 and Zing is joining the party.

Jonathan

 

[Tranona]

Similarly as to the notion that larger anchors hold better in poor ground, that again a daft request. It's a fundamental calculation in civil engineering that a ground anchor or foundations or any structure or device increases its holding capacity with its area. It's the same with anchors and somethings you shouldn't be asking for proof for.

You miss out the most important word "Potential". Nobody is suggesting that larger anchors of the same design have POTENTIALLY higher holding power (but not necessarily setting performance). The argument put forward by myself and others is whether that potential can be accessed by a boat for which a smaller size of the same anchor is recommended. The so called comparative tests do not do what is important, and that is match identical boats in identical situations with different size anchors of the same design. They just apply a fixed load rather than an actual load related to a boat in specific conditions, therefore ignoring whether the boat can actually apply that load.

BTW I fail to see why you are questioning the ability of some designs of anchors to be more effective at lower weight - surely that is obvious when just about all the objective tests show that smaller and lighter NG anchors outperform older heavier designs. An aluminium Fortress performs equally as well as the steel version. Why would one not take advantage of superior performance of some designs by choosing a smaller, lighter and cheaper example?