Anchor snubber- long stretchy rope or rely on catenary

[Neeves]

I am fascinated that everyone has studiously ignored the loss of a catamaran using an NG anchor, which surely generates greater concerns than whether an anchor twitches or not and what is the definition of twitch.

Odd priorities.

Jonathan

 

[Neeves]

The thread on CF on shackles has some useful information on quality, 'rated' etc.

http://www.cruisersforum.com/forums/f118/rated-anchor-shackle-brands-208292-2.html

I was in HK a few years ago and was searching the couple of streets that specialise in lifting gear.

Outside one shop was an oldish man with 2 piles of shackles, galvanised (or silver coloured). One pile was simply marked with size. The other pile was marked 'Holland', size, and WLL of (I don't recall). He had a big hammer and a pile of dies (I think that is what they are called). He was skilfully indenting, so anyone of any knowledge would see the difference, the unmarked pile. For completeness maybe they sprayed up with silver paint (commonly used to cover defects in gal on anchors).

The shackles had green pins.

Afterwards I did wish I had bought some and taken pictures but I was afraid to use the camera - it was unknown territory!

As the man says in his post - buy your brand name shackles from a source with some integrity.

I get regular offers of people, in China, selling Rocna anchors, one had a picture of a Mantus, another has offered Spade. Anchor Right had a big problem with SARCAs from China. There are hundreds of shackle makers in China and a good few chain makers.

Its a pity there OP is opting for what looks like a compromised quality - The issue of a 50% drop in strength if the shackle is side loaded has not been emphasised - as has been done on similar threads here. But they do appear to recognised the excellence of Grade B over Grade A shackles.

Jonathan

 

[RichardS]

I am fascinated that everyone has studiously ignored the loss of a catamaran using an NG anchor, which surely generates greater concerns than whether an anchor twitches or not and what is the definition of twitch.

Odd priorities.

Jonathan

I haven't read the report but I'm not sure what point you're making Jonathan.

Boats have been lost using Last Gen anchors and boats have been lost using Next Gen anchors. But so what. In general, and across the usual seabeds one would choose for anchoring, there cannot be any remaining argument against NG anchors being superior to LG anchors.

Can there?

Richard

 

[Neeves]

The point was multi-fold

Everyone, including me, suggests that NG anchors set and hold reliably and in the unlikely event they are unseated by a wind change - reset quickly.

Reports of old gen anchors dragging are common place, every thread has someone making mention of how unreliable they are (I'm not sure how statistical significant these reports might be). No-one when asked admits to their NG anchor dragging.

http://www.ybw.com/forums/showthread.php?502469-Dragging-of-anchors&highlight=Dragging+of+anchors

The fact this yacht was lost might suggest some complacency

Other than Morgans Cloud negative comment on NG anchors are like hens teeth. In fact anyone critisizing an NG anchor is vilified (hence they fear have (that they express) of starting an anchor thread.

The numbers of report of losses as a result of 'failure' of an NG anchor seem, to me, to be rare (maybe I need to spend more time on forum ).

The reality is not quite so rosy - I think it needs underlining - sorry if it spoils an member's day, or week.

Images of old gen anchor show how badly they set, image of NG anchor invariably show them well set, or that is commonly the description.

There is no perfect anchor. Don't be complacent.

Jonathan

 

[RichardS]

The point was multi-fold

Everyone, including me, suggests that NG anchors set and hold reliably and in the unlikely event they are unseated by a wind change - reset quickly.

Reports of old gen anchors dragging are common place, every thread has someone making mention of how unreliable they are (I'm not sure how statistical significant these reports might be). No-one when asked admits to their NG anchor dragging.

http://www.ybw.com/forums/showthread.php?502469-Dragging-of-anchors&highlight=Dragging+of+anchors

The fact this yacht was lost might suggest some complacency

Other than Morgans Cloud negative comment on NG anchors are like hens teeth. In fact anyone critisizing an NG anchor is vilified (hence they fear have (that they express) of starting an anchor thread.

The numbers of report of losses as a result of 'failure' of an NG anchor seem, to me, to be rare (maybe I need to spend more time on forum ).

The reality is not quite so rosy - I think it needs underlining - sorry if it spoils an member's day, or week.

Images of old gen anchor show how badly they set, image of NG anchor invariably show them well set, or that is commonly the description.

There is no perfect anchor. Don't be complacent.

Jonathan

Bearing in mind all that is general understanding, and the fact that I doubt whether many of us on the forum would consider ourselves to be guilty of complacency, I still can't see the connection between the above and your observation that you are "fascinated that everyone has studiously ignored the loss of a catamaran using an NG anchor .... Odd priorities."

Richard

 

[Neeves]

I thought it might invoke comment - not a deathly silence, but maybe people are still in shock, or denial.

 

[RupertW]

I thought it might invoke comment - not a deathly silence, but maybe people are still in shock, or denial.

I think there is nothing to say about it. An NG anchor can drag if its set in the wrong place and I think everybody accepts that. The silence from me was because there are no facts at all to comment on or learn from.

 

[RupertW]

Rupert,

You are an expert on Delta, these are both genuine Delta?

I'm no expert on Delta - quite the opposite, I know nothing about their construction or their design.

I just know I acquired 15kg anchor for my 12.5m monohull that looks a bit like a Delta so that's what I call it.

I am a bit of a gadget freak and a neophile so would love to get an NG anchor but my "Delta" just keeps on holding in all reasonable surfaces and in good and nasty conditions so the replacement keeps dropping to the bottom of my list and hasn't dragged a single time in 8 years once properly set, whether at our usual 3:1 scope or at a more generous one.

The only observations I can make are that my anchor seems to move a greater distance from touching the bottom to setting than the NG anchors I see around me and that when trying to set it in weed it will often not penetrate through the weed to the bottom but I can't really compare that to NG anchors because an NG anchor in weed is as invisible as an old style anchor in weed.

Edit: I would just add that weed is less of an issue now because I've just moved the boat from a country that keeps bays turquoise by dredging and ploughing up posidonia without success because it is so persistent and fast growing to a country whose identical posidonia is so delicate that dropping a hairpin into it causes it to instantly shrivel up and call for help from special police. So it's sandy anchoring only now.

 

[Neeves]

Thank Rupert,

I think evidence is that if you can get your Delta (CQR/Bruce), or a decent copy, to set then it will hold. Having said that it may not hold in if the yacht is exposed to 50 knots - but few would be anchored in 50 knots anyway

In terms of weed - there is weed and more, different weed and it comes in different densities. It is difficult to define, as we all have different ideas of 'thickness'. As you suggest anchoring in weed is frowned on, and actively discouraged, in many places - and sand is so much safer.


To return to twitching, maybe the term should be intermittently vibrating.

I have to confess that the idea is not mine (and I find it distasteful to not acknowledge the original source of ideas and knowledge). Vyv made the observation some many months ago. I had less enthusiasm for diving on anchors and lacked the imagination to actual spend time touching it. Rather than dismiss the idea out of hand I thought the phenomena merited investigation - and would have to agree with Vyv. It does happen - whenever the shackle/anchor is under any tension and the chain is moving (more pronounced when the yacht is moving back and forward, even slightly). It is more noticeable in stronger winds.

If the intermittent vibration (the anchor does not change location) is such that it reduces shear strength - this might explain why an apparently well set anchor might then drag and contradictorily - or set more deeply. Buried chain appears to reduce the effect.

But credit to Vyv.

Jonathan

 

[MM5AHO]

NG anchors can drag, so question of it. Any anchor can.
I tried, as an experiment setting a Knox anchor on boulders of about the size of the anchor. It rumbled over many before it got any grip.
To deny that the obviously possible is impossible is just silly.

 

[Neeves]

NG anchors can drag, so question of it. Any anchor can.
I tried, as an experiment setting a Knox anchor on boulders of about the size of the anchor. It rumbled over many before it got any grip.
To deny that the obviously possible is impossible is just silly.

I agree

I watch people anchoring - the common practice is to deploy the anchor with the yacht moving slowly backwards. The anchor can be of any type, NG, genuine old gen or any nefarious copy. Yacht stops, crew disappear into the cockpit or down below (depends on weather). No attempt to back up, other than drift, at all. They may take transits, the may set an anchor alarm - how would I know. I have never ever seen anyone dive on their anchor.

People do appear to think their anchor is infallible (I suspect infallible is the wrong word?) reliable, predictable and dependable. I wonder why?

I have only seen yachts dragging once - a row of us were caught out with an optimistic forecast. The wind did not match the max of 15knots onshore but achieved a bracing 25 knots, there was a 3 mile fetch - so big seas developed. One by one the yachts dragged, exclusively old gen - we struggled to break our anchor out - the snatch loads with the chain taut were awesome (up at the 5/600kg mark - how do I know I've measured the same) - which is why I only recommend Crosby/Campbell shackles (a 316 stainless shackle, of which I see many on anchor shanks, would be beyond the point of bending if side loaded (how do I know......). The shackle would then need to be cut off - just the task at 2am!

Jonathan