Anchors - Bigger is Better ?

[roland stockham]

The way I was taught was that (but might now be seen as 'out of date');

1. An anchor that is heavy for its physical dimensions tends to dig in better in hard pack or weed but is more prone to bending in rock. If it's the other way round it's going to be better in soft mud.
2. Unless seriously undersize for the boat or the or the holding is very poor the seabed won't fail and let the anchor drag through it.
3. Anchors pull out because either there is not enough length or weight in the scope so the cable comes taught (you loose the cantinary effect). This caused an upward pull on the shaft and any snatching is transmitted straight to the anchor, pretty much guaranteed to pluck anything out.
4. The ground tackle should be seen as a complete system and matched to the windage of the boat plus how quietly she lays to her anchor in a blow and chop - light and lively needs more tackle.
5. the classic formula of 3x depth for chain or 5x for rope is only good for in moderate weather, double it for each number on the Beaufort scale above 5 so in a gale (8) you want 12x depth. If its more than that put everything you have out and keep a watch!
6. If it's bad and the anchorage is crowded go elsewhere because even if you don't drag everyone else is on 'short scope' so one of them probably will (or at least be to windward...)

Always worked for me and I have anchored in 50+ knots with no problems

In theory because I have never done it (and hope not to!) in hurricain conditions I would probably look for deeper water to get a smoother ride and put out a single 200m rode (150m chain + 50m rope for 'spring') with tandem 45lb anchors (35ft boat) rather than multiple anchors on shorter rodes.

[Stumble]

Originally Posted by JonJo

I believe, correct me if I'm wrong - as I am sure someone (or everyone) will, the other recommendation is to go down in chain size and use G7 chain. So the recommendation is 'bigger anchor and smaller chain'. They might also suggest longer chain.

I wonder what size of windlass is used to lift a mud filled 110kg Rocna (and what on earth do you do if the windlass is inoperative? - or does everyone have 100% relaible windlass?).

Jonathan

Yup that correct. High strength chain means you can go with smaller and lighter sizes for the same strength, which they then put back into the size of the anchor.

Remember a windlass is sized based upon the total weight of the anchor plus chain. So if you go to lighter but smaller chain and a huge anchor you can probably go down in size on your windlass.

300' BBB chain weights 500lbs (2750lbs working load)
Plus a 65lbs anchor
=565lbs

Vs

300' 1/4" Grade 70 weights 222lbs (3150lbs working load)
Plus 242lbs anchor (110kg)
=464lbs

In reality you are probably in the same size windlass, but the system total is less.


I have never had an electric windlass fail (until tomorrow probably). But every one has a manual backup. Worst case you hook a line to it, and pull it up with a winch. At least you back won't be killing you from lifting that excess chain weight when you begin.

[Delfin]

Originally Posted by Dockhead

It looks bad to me - dangerously misconceived. Fragile.

The Wasi doesn't appear to be made anymore. The dimensions of the Ultra swivel are about identical to the Wasi, and is tested in the 1/2" size I have to double the breaking strength (38,000 lbs) of my G4 chain, whatever the angle of pull. Fragile?

[JonJo]

The concept of Bigger is Better is predicated by the idea that bigger actually means heavier and that the anchors under consideration are modern high holding capacity anchors.

I offer some alternate ideas. The three anchors on the right each weigh about 8kg, they are all alloy, they are all demountable and they represent a cross section of some of the current anchor concepts available. The anchor on the left is also demountable and extends the range of anchor concepts but weighs around 15kgs. I would have illustrated Rocna, Supreme, Ultra, steel Spade or steel Excel etc - but I do not have 15/16kg models and/or not handy.

We could scale up up the weights to 20kg for the alloys and 40kg for the galvanised, of which I show just the one model. The question remains the same.

Given the similarity of weights what are the arguments against a choice of 2 from three from the ones on the right (so 16kg total), or the one on the left, 15kg (or the other models not illustrated, Ultra, steel Spade, steel Excel, Rocna, Supreme, maybe Boss).

[noelex 77]

Originally Posted by JonJo

I wonder what size of windlass is used to lift a mud filled 110kg Rocna (and what on earth do you do if the windlass is inoperative? - or does everyone have 100% relaible windlass?).

They use a standard Maxwell V4000. With the 110kg (240lb) Rocna
My own boat has a Muir 3500 with a 55 kg anchor
I think Jedi had a Maxwell 3500 with a 80 kg anchor

These are all standard 12v windlasses, on the large size, as everything on a cruising boat should be, (with 1200w/1500w motors instead of the more typical 1000/1200w motors) but as most of the weight is in the chain generally boats can go +2 or so in size without even changing the chain, but going down in chain size with G7 may be necessary (from an anchor winch strength point of view) on some production boats.

Anchor winch failure is something to consider on every boat. Fortunately yachts have powerful sheet /halyard winches that will handle the loads, but it worth thinking how you will lead the lines and if you need any additional equipment, blocks etc. The anchor size only makes makes a difference from breakout to surface. Lightweight chain makes a big difference especially if you anchor in deeper water. If you can pull the chain up by hand then use the sheet/halyard winches to pull up the chain/anchor weight you have a reasonably practical system.

One of the important requirements (without an anchor winch) is, surprisingly, a good anchor that sets reliably.
Pulling up the anchor chain combination by hand when leaving is bad enough, but when dropping the anchor if it does not set and needs to be lifted and re dropped multiple times it will exhaust the best crew, even if you only lift the anchor just off the bottom. I have been there on a previous boat with no anchor winch and a CQR and it is no fun.

[noelex 77]

Steve Dashew is very sensible experienced cruiser. With a lot of great ideas. Here is his thoughts on anchoring gear for his FPB series.

Note how on his smaller 64 foot boat he fitted exactly the same sized anchor as on his 83 foot boat. If the gear can handle it why not?
This is exactly my thinking fit the biggest anchor you can comfortably handle.
Quote are below from DashewOffshore.com - the serious cruising sailor's website

On the FPB 83 we started with a 240-pound (110kg) ROCNA anchor - the best hook we have ever used, which has tested at twice the holding power of our traditional Bruce anchor. This is coupled to 3/8" (9.6mm) schedule seven high-strength chain (26,000 pound/11,700kg breaking strength). The windlass is a very robust Maxwell V4000. There are a pair of large Fortress aluminum hooks for kedges and back up. This oversized gear allows us to anchor on two to one scope, and have reasonable holding.

The FPB 64 will have lower anchoring loads than the FPB 83. There is less windage and the FPB 64 is lighter. Our ground tackle package for this design? Exactly the same as for the FPB 83. The FPB 64 can handle this weight and we like the even higher factors of safety this system offers (you can never have too much holding power in your ground tackle).

When reading these quotes rember the FPB series are very long and thin with no mast rigging windage. The FPB 64 would be equilvant in anchor loads to a smaller Yacht. The FPB 64 anchor is already 3.75 lbs per foot and the equivent in sailboat terms would probably be over 4 lb per foot. With the best, or at least one of the best anchors in the world.

Even I think that may be getting too big , but he has a lot of anchoring experience and his views should not be dismissed.

[noelex 77]

Originally Posted by JonJo

Given the similarity of weights what are the arguments against a choice of 2 from three from the ones on the right (so 16kg total), or the one on the left, 15kg (or the other models not illustrated, Ultra, steel Spade, steel Excel, Rocna, Supreme, maybe Boss).

I don't see "bigger is better" excluding aluminium anchors. A good "big" aluminium anchor is fine by me. The aluminium anchors are physically big, rather than than having a large weight, but the principal of fitting a "large" anchor still holds.

The problem is that there is no proven good bower aluminium anchors. The Fortress is fantastic and every boat should have one, but does not manage to reset as well as should so is not suitable for a bower anchor.

The aluminium Spade has been a great disappointment in my view. The. Steel Spade is excellent, but the aluminium version does not work as well. The transition has made an excellent anchor merely good.

The aluminium Excel is an exciting new addition. An aluminium anchor has a lot of advantages with weight distribution and fluke sharpness. It should be able to out perform the steel version, but the only anchor that has achieved this so far is the Fortress. Time will tell if the aluminium Excel can do this.

Do the yellow shanks and roll bar increase holding power

[Stumble]

The best part about he Fortress is that as a backup anchor it can be disassembled and stored in a compact bag in the hold. So if something were to happen to the big primary it is a relatively easy process to get it into service.

As a primary anchor, they get very large physically very quickly, which requires some real work to fit on most bow rollers. And because of all the protrusions they have a habit of catching things... Generally sails in my experience.

[JonJo]

YELLOW,

It has significantly increased hold - good anchors are commonly stolen (anywhere round the world), particularly Ultra's. No-one has stolen any of my yellow painted anchors yet - I hold onto them, so their holding is good

I recall you do not think yellow shows up too well underwater, you do it so often - you should know. But I find my memory of views underwater becomes distorted and then fades but photographs (do we still call them photos?) last a bit longer and yellow shows up quite well. And photographs, unlike my memory, do not lie - though with image manipulation anything is possible. Usually the last thing to disappear, under the seabed, is the shank and the yellows stands out.

Jonathan

[JonJo]

Noelex,

I have read negative comments from a few on their difficulty of getting an alloy Spade to work in a hard seabed. Maybe there are hard and even harder seabeds. In those hard seabeds here, notorious for being hard, we have not found this an issue at all. Their ability to set anywhere else (in any other seabed) that any other modern anchor can call home, comfortably, suggests to me that if this is their achilles heel - its not worse than roll bar anchors clogging in weed beds (where an anchor without a roll bar will set more easily). Consequently, like all anchors - its a compromise, alloy Spades handle weed better than do roll bar anchors and maybe roll bar anchors handle hard sand (better than alloy Spades). But the alloy Spade has that extra advantage (they now call it The X Factor). Its light.- and alloys for some reason are currently, largely demountable.

I have no idea of the frequency of, really, hard seabeds (those that defy and alloy Spade), but there do seem an awful lot with weed!

Its a balance and it merits comparing the characteristics of all - rather than picking our the weakness (if that is a frequent issue) of one.

I do not think anyone would deny that a large Fortress is a monster (in terms of size). But when a storm is forecast (and most storms (unless tropical) come in fairly consistently forecast directions) then resetting is not an issue. But which has the most holding capacity a 15kg Rocna (or other) or a 15kg Fortress - and which would you want to rely on (subsititute 50kg if 15kg is too small for you). But again - a 15kg Rocna or a 8kg Fortress - as even a 8kg Fortress has a larger surface area than a 15kg modern gal anchor.

So what is the view?

Jonathan

[Fortress]

Originally Posted by noelex 77

The problem is that there is no proven good bower aluminium anchors. D

"I've used the Fortress as my primary anchor in sand and mud bottoms for more than 20 years. I have found the Fortress to be thoroughly dependable."

- Elbert S. Maloney, 90+ years old, author for several decades of "Chapman Piloting: Seamanship & Small Boat Handling"

[Delfin]

Originally Posted by noelex 77

The problem is that there is no proven good bower aluminium anchors. The Fortress is fantastic and every boat should have one, but does not manage to reset as well as should so is not suitable for a bower anchor.

Odd that the USCG uses them as the bower anchor on their 87' 91 lt Marine Protector class cutters.

[noelex 77]

Originally Posted by JonJo

Maybe there are hard and even harder seabeds. In those hard seabeds here, notorious for being hard, we have not found this an issue at all.

I never found any hard seabeds when cruising Australia (however, it is a big place so maybe they do exist)

Originally Posted by JonJo

its not worse than roll bar anchors clogging in weed beds (where an anchor without a roll bar will set more easily). Consequently, like all anchors - its a compromise, alloy Spades handle weed better than do roll bar anchors and maybe roll bar anchors handle hard sand (better than alloy Spades).

I have found the Spade steel or aluminium (the later is slightly worse) does worse than the roll bar anchors in weed.

It is very difficult to consensus on anchor performance in weed. A significant problem is that weed varies significantly in composition from location to location as does the substrate underneath. It may be that we are all right, and an anchor that does well in weed in one area does poorly in a different type of weed.

Another problem is that often the weed is tough enough that it will hold the anchor reasonably without the anchor setting into the substrate. In tough weed the anchor will hold full reverse and reasonable wind strengths (say 35 knots ) without gripping into the substrate. Unfortunately if the wind picks up the boat will drag. Even looking at the set from the surface is no help as the anchor often disappears under the weed. Diving down and feeling with your hands is the only way to tell if the anchor has actually cut through the weed (sometimes when you pull it up there is a clue)

Anyway my experience is Rocna/MS is significantly superior in weed. I think the problem is probably the thick toe of the Spade verses the thin knife like toe of the roll bar anchors.

See picture: It is tough to drive this through weed.

[noelex 77]

Originally Posted by Delfin

Odd that the USCG uses them as the bower anchor on their 87' 91 lt Marine Protector class cutters.

I am a big fan of Fortress anchors. To prove it I own two (actually a Fortress and a Guardian). They do things that no other anchor will do and every boat should have one.

However they do have a weakness when resetting to a change in direction of pull.
When diving I often see them trip out when other anchors stay buried and rotate around. Most often the Fortress will reset again and the owner is unaware what is occurring, but it is a weakness that should be considered when using them.

I am not sure what the requirement is for the USCG vessel. I suspect there anchoring pattern is very different to our recreational vessels. Do they anchor much overnight with no one on anchor watch? I don't know but suspect not.
The Fortress excels at extremely high holding when given a constant direction of pull and if they have selected correctly this will feature as their primary requirement.

On the other hand perhaps they have never dived and taken a look

[Delfin]

Originally Posted by noelex 77

I am a big fan of Fortress anchors. To prove it I own two (actually a Fortress and a Guardian). They do things that no other anchor will do and every boat should have one.

However they do have a weakness when resetting to a change in direction of pull.
When diving I often see them trip out when other anchors stay buried and rotate around. Most often the Fortress will reset again and the owner is unaware what is occurring, but it is a weakness that should be considered when using them.

I am not sure what the requirement is for the USCG vessel. I suspect there anchoring pattern is very different to our recreational vessels. Do they anchor much overnight with no one on anchor watch? I don't know but suspect not.
The Fortress excels at extremely high holding when given a constant direction of pull and if they have selected correctly this will feature as their primary requirement.

On the other hand perhaps they have never dived and taken a look

Yes, they anchor overnight, as that class of vessel is designed to go out for up to 5 days. The Navy doesn't buy equipment on a whim, but after testing. They use the anchor as a bower and the only problem I have heard off that they have had is losing one after it buried itself too deeply to be recovered. I have also seen one with a bent bar on the Osprey.