Bigger is better, part 2

[JonJo]

Originally Posted by noelex 77

A quick search of CF came up with some examples. Such as this one on:



The thread is here:
http://www.cruisersforum.com/forums/...ain-21145.html



I don't think your 8mm G3 chain is a terrible choice. It is an acceptable compromise between cost and performance. However I think if cost was no object 8mm G7 would be better for your sized boat.

I think the thread you provide simply underlines the fact that chains do not break.

If cost was no object I'd buy 1/4inch G7 chain and a new matching windlass from West Marine. Having survived all that Australia can throw at us we are comfortable with the strength of 8mm G3 but would prefer the same strength, or similar, and less weight (but we are not prepared to buy a new windlass - its simply not cost effective).

Jonathan

[JonJo]

Originally Posted by noelex 77

I think you once said that you wanted an anchor shank that has zero risk of bending. (I don't quite agree. With anchor shank and tip strength and think we want a compromise between performance and risk of bending.). We should at least adopt same, or higher, standards for anchor chain.

I think you have an anchor with a Bis 80 shank, as is mine - unless now that you disagree with your choice, you got rid of it.

So you disagree with me, but keep the same unbendable shank that I advocate?

The logic defeats me.

Jonathan

[sailorboy1]

I don't really see the point of having a chain that is probably way stronger than my boats attachment point. I also don't see any advantage of having a chain stronger than what I could expect my oversized new generation anchor to hold.

[DoubleWhisky]

Originally Posted by JonJo

IYou also need to be less enamoured with catenary and you need to use snubber(s).
Jonathan

I must admit im much enamoured with catenary, and not so much with snubbers

But I must also admit it is because of Med-mooring, not because of anchoring out.

Please, let me elaborate. Med-mooring is not only about to pack more boats at given length of the quay without rafting. There is also the second reason for this. A lot of harbours in Eastern Med are natural harbours, squeezed into deep bights and sometime protected by a piece of breakwater. They are safe form the weather mainly, as they are in places proven as safe by hundreds of years. But now new danger arose - huge, fast ferries are passing the harbours on full speed, sending their monstrous bow and stern waves into the harbours. There are some harbours (Kioni and Frikes on Ithaca come first to mind), where mooring alongside the quay is straight recipe for disaster. Boat can be taken two or three feet down, than four or six up and thrown side to the wall in seconds. Many was seriously damaged this way and in fact You just can not fender Your boat for such situation. In other places wash from turning ferries is enough to pop up all fenders, nevertheless how long and heavy they are.
In such a harbours the Med-mooring is the matter of safety, not convenience, but You need to be moored properly. In other words, You need Your anchor to be big, heavy and set like a rock, You need Your rode to be all chain, and better on heavier side (here some, but not much catenary comes to play, and to make a small catenary work, You need a weight), You need Your stern pulled several feets from the wall, You need good, somewhat elastic warps on Your stern, arranged in a way preventing chafe. The fairleads with rollers are good for this, and I - for example - have twelve of them around a deck (if somebody want to have a look at rolled fairleads, as they are not very popular - in the album "Boat & Crew" on my CF profile the last four photos show some details of deck arrangement - no need to repost them here)
One thing You do not need for Med-mooring is a normal snubber. On the wave sent into the harbour by passing ferry (think 25.000 BRT doing 27 knots) any snubber hook can jump out and the boat will crash against the wall - not nice. I use short lines to the cleats, but only to take some stress from windlass, never allowing the part of the chain hang freely, as is normal when using snubber.

My best regards

Tomasz

[Horror Hotel]

I don't recall the bigger is better argument ever being about med mooring. And in regards to the above story about 1/4" chain breaking, 1/4" chain is tiny and I could easily envision is breaking under a huge snapping load. Especially if it was old and been in service for many years. Would you try to pull a Toyota out of a ditch 1/4" chain? Not a tow guy for sure .

[DoubleWhisky]

Originally Posted by Horror Hotel

I don't recall the bigger is better argument ever being about med mooring.

In US You probably do not have many occasions to be Med-moored, I assume
This argument was mentioned several times in original thread.
Med-mooring in stronger winds (especially crosswinds) and with waves inside the harbour (for example caused by shipping traffic nearby) can be very testing for anchoring gear.
Once upon a time it happened in one of the harbours in Saronic Gulf (Methana probably, but I'm not sure at the moment) that some boats were crashed against the wall heavily, and at least one landed ON the quay, just because the big ferry cut a corner a little and passed closer to the harbour entrance than normally... Other boats survived, being anchored better...

Best regards

Tomasz

[noelex 77]

Originally Posted by JonJo

I think you have an anchor with a Bis 80 shank, as is mine - unless now that you disagree with your choice, you got rid of it.

So you disagree with me, but keep the same unbendable shank that I advocate?

The logic defeats me.

Jonathan

The reality is that you are much, more likely to damage your boat from dragging than the very small risk of breaking your chain, bending the shank, or tip of your anchor.

Therefore I think the greatest emphasis should be on the anchor performance.

Unfortunatly there is trade off between shank/tip strength and performance for most designs.

Manson claim there has never been a bent Manson Supreme shank so I suspect my NZ Rocna shank (of similar construction) is also extremely unlikely to bend.

The Bis 80 shank on my NZ Rocna is great, but I think a slightly thinner/less deep shank design would improve the performance further. This would be a better compromise than the goal to build a built proof shank. Similarly a sharper tip and leading edge would improve the performance at the expense of a slight risk of bending these surfaces.

This is no different than other equipment on my yacht. I have no illusions that my mast is "indestructible" only that it is a reasonable compromise between strength and performance.

Manson may be thinking the same way making the shank of their new Boss anchor thinner.

BIB has a role to play in this. As the anchor is oversized the risk of bending the shank, or tip becomes less. So those choosing a bigger anchor can afford to err slightly on the side of slightly thinner/less deep shanks and sharper tips. However It is important that the compromise does not become excessive.


Unfortunately the commercial reality is that we cannot custom order these designs. We are forced to accept the models manufactures offer. There is great commercial pressure to produce anchor shanks that cannot bend under any circumstances. I would prefer to see a sensible compromise where the performance of the anchor is optimised at the expense of a very slight risk of bending the shank or tip.

[DoubleWhisky]

Originally Posted by noelex 77

The reality is that you are much, more likely to damage your boat from dragging than the very small risk of breaking your chain, bending the shank, or tip of your anchor.

Therefore I think the greatest emphasis should be on the anchor performance.

Unfortunatly there is trade off between shank/tip strength and performance for most designs.

The Bis 80 shank on my NZ Rocna is great, but I think a slightly thinner/less deep shank design would improve the performance further. This would be a better compromise than the goal to build a bend proof shank. Similarly a sharper tip and leading edge would improve the performance at the expense of a slight risk of bending these surfaces.

BIB has a role to play in this. As the anchor is oversized the risk of bending the shank, or tip becomes less. So those choosing a bigger anchor can afford to err slightly on the side of slightly thinner/less deep shanks and sharper tips. However It is important that the compromise does not become excessive.

Unfortunately the commercial reality is that we cannot custom order these designs. We are forced to accept the models manufactures offer. There is great commercial pressure to produce anchor shanks that cannot bend under any circumstances. I would prefer to see a sensible compromise where the performance of the anchor is optimised at the expense of a very slight risk of bending the shank or tip.

I can agree with You, Noelex, and I must tell that after all reading, examining of photos and so on I'm going to be more and more interested in Excel (and its sharp tip). On the other hand, after all bad experiences with convex anchors I'm still in some doubt about convex design of Excel.
Probably I can not go further with any conclusions regarding this design without using one in real life!

Cheers,

Tomasz

[DefinitelyMe]

Originally Posted by JonJo

find me anyone that has actually broken branded G3 and I might think again

Many times, but in mooring applications rather than anchoring. I don't see much difference though in terms of the loads that are applied to the chain. I've seen brand-new 7/16", 1/2" and even 5/8" G3 chain fail on several occasions, usually when subjected to shock loading but not always in particularly adverse weather conditions. Neither G4 or G7 chain is available here in Bermuda. I can't afford G7 but having seen what i've seen (i used to work in the mooring industry) i will be getting at least 3/8" G4 to go with my 25kg rocna as soon as i can get it. If i could afford G7 i would get it, but the size would stay the same as my windlass is from 1977 so the gypsy is staying for good!...... and I use a very stretchy snubber line!

[noelex 77]

Med mooring is a popular and even necessary way of anchoring in some parts of the world so I think it deserves some consideration if you are planning to sail long distances.

I am generally in favour of a lighter rode, but Med mooring is an anchoring style where there is some significant advantage in a heavier rode.

However the first requirement when Med mooring is a very secure anchor that works in an anchor substrate that has often been churned up. Some of the convex anchors are poor in this regard, gradually creeping backwards with load. A few feet of movement does not have much impact normally, but becomes significant if the rocks, or the quay are only a short distance away.

It also helps considerably to have lots of chain this makes judging where to drop the chain much easier. You can drop your anchor further out away from other anchors. Unfortunately lots of heavy chain is difficult for most boats to carry. The reality for most boats is lots of light chain, or a shorter amount of heavier chain.

Med mooring is one of the few times where an anchor angel (or chum) can be helpful.

Make sure you still take the the load off the anchor winch. A short snubber is still fine. There are ways of attaching this to chain that are very secure (such as a soft shackle)

[noelex 77]

Originally Posted by DoubleWhisky

I can agree with You, Noelex, and I must tell that after all reading, examining of photos and so on I'm going to be more and more interested in Excel (and its sharp tip). On the other hand, after all bad experiences with convex anchors I'm still in some doubt about convex design of Excel.

I think the concave rollbar anchors and the Steel spade are the better choice. (The Ultra also shows some promise).

The Excel has sharp leading edge which is a bonus over other convex anchors such as the Delta and Kobra. I have some concerns that it may be too thin. I have seen two bent tips on different "Excel shaped" anchors, but it is very hard to come to any firm conclusions from only a small number of examples.

In both cases it was only the very tip that was bent and the risk will less if you subscribe to the BIB philosophy. Time will tell.

[DoubleWhisky]

Originally Posted by noelex 77

However the first requirement when Med mooring is a very secure anchor that works in an anchor substrate that has often been churned up. Some of the convex anchors are poor in this regard, gradually creeping backwards with load. A few feet of movement does not have much impact normally, but becomes significant if the rocks, or the quay are only a short distance away.

It is exactly the point why I trust concave designs more for Med-mooring

Originally Posted by noelex 77

Make sure you still take the the load off the anchor winch. A short snubber is still fine. There are ways of attaching this to chain that are very secure (such as a soft shackle)

Generally I'm in agreement with You - the load should be taken off from the winch. Details are worth discussion, but rather not in this thread - too much of a drift

Best regrads

Tomasz

[DoubleWhisky]

Originally Posted by noelex 77

Med mooring is a popular and even necessary way of anchoring in some parts of the world so I think it deserves some consideration if you are planning to sail long distances.

I was thinking about starting specific thread regarding Med - mooring, but I'm not sure if it will be of interest here

[cfarrar]

JJ,

Our newly acquired 44' monohull came with a 20Kg Delta that we promptly traded for a 33Kg Rocna. The boat also came with 50M of 12mm G3 chain, and I wanted to swap it out for about 90M of 5/16" or 8mm G7. However, in addition to the problem of cost, I can't find a gypsy for the Lofrans Tigress that will accept the G7 chain. I will probably end up with 5/16" G4 chain (haven't pulled the trigger, yet). So, while I will not have the strongest chain possible, I am basically following the BIB theory - bigger anchor, lighter chain, less weight on the bow, more holding power.

[noelex 77]

One advantage of marine metric chain is that sizes do not vary with the strengths (G3,G4, G5, G7).
For 8mm chain there is only one size normally listed as Din766, but sometimes known as ISO4565. A gypsy Lofrans Tigress is available in 8mm ISO4565. 8mm Din766 G7 chain is available from Maggi and others. My understanding is that Din766 and ISO4565 are identical link sizes (in 8mm) so it should fit.

Your weight of anchor and chain will alter from 210kg to 164kg and you will have longer chain and a bigger anchor. Your chain strength will go down, but is still acceptable. As an alternative 10mm G7 would keep the strength the same as your existing 12mm G3 with almost no change in weight from your existing set up (but with longer chain and a bigger anchor). 10mm G7 is slightly overkill for your sized and weight boat