Anchor question,

[alahol2]

The earlier quoted web page... http://www.spade-anchor.co.uk/S60.htm for the S60 states...
Monohull
Length <25' (<7.5m)
Displacement <2T
So for a 32ft, 4tonne boat the S60 sounds to be seriously under spec'd?

 

[doug748]

I've had two roll hoop Rocnas, one Spade, and a Rocna Vulcan.

In reverse order....

The Rocna Vulcan was bought because I wanted a Rocna but without the roll bar (it didn't fit with the roll bar). I didn't like it because it often took two or three tries to get a grip, and was prone to dragging in mud.

The spade was an anchor that I was keen to try given the great test reviews. However, I found that in sand it occasionally dragged (never broke free). In mud it was fine. Like an earlier poster remarked, it was easier to clean off the mud on the Spade using a boat hook (than the roll bar Rocna).

I first tried the roll bar Rocna four boats ago after being underwhelmed by the performance of the Delta. It performed well in most of the anchorages we tried along the Channel, mainly on UK side. In mud, the suction sometimes made it difficult to get up. We sometimes had to motor over it to break it free after a couple of days in the same spot. It was difficult to clean mud from. The roll bar seems to hold it in.

When I bought another Rocna for the next boat, I was a bit unnerved by all the bad publicity about the Chinese made bendy shanks. Also, the U.K. based PR person who seemed to be employed by Rocna to deflect any owners concern, was so shady with their excuses that I bought the spade anchor.

My anchoring experience is nowhere near as extensive as many other folk on here, but I havr used both the Rocna and a Spade.

I have just bought my third Rocna for my new yacht and so I guess my vote is for the Rocna.

However, I honestly don't think you will go wrong with either of your choices.

As for sizing, I can't remember what I chose, but I always go to the top end of the choices for my boats, and always assume that I will carry the maximum amount of weight for the calculation. I also tend to only use a full chain rode. Not sure if this makes a difference.

Garold

Thanks Garold, for taking the trouble to respond with such a comprehensive post.

 

[doug748]

Doug, were have you seen a Spade S60 for £280 ? They were a lot more than the Rocna when I was looking a couple of years ago. Settled on the Rocna in the end, don't they have thin shanks compared to a similar sized Delta

I forgot to ask Pete. How are you getting on with the Rocna - apart from wondering about the skinny shank? Have you had much of a chance to give it a test?

 

[Strolls]

The earlier quoted web page... http://www.spade-anchor.co.uk/S60.htm for the S60 states...
Monohull
Length <25' (<7.5m)
Displacement <2T
So for a 32ft, 4tonne boat the S60 sounds to be seriously under spec'd?

Through the site's "selector wizard" it's described as suitable as "main anchor for fair weather coastal cruising".

http://www.spade-anchor.co.uk/sd_range11.htm​

 

[charles_reed]

IMHO Spade is the better all rounder (I don't use either, but a more reasonably priced competitor).
Your choice may be a trifle on the light side for anything but "lunch" anchoring. I have a lighter, shorter boat and recommended Spade and Rocna were way larger than the recommended size of the one I chose, which is larger than the ones you're considering.
If you need to save weight it appears a better option to go for a light chain and heavy anchor.

 

[Babylon]

... If you need to save weight it appears a better option to go for a light chain and heavy anchor.

What's the current thinking on the catenary effect?

 

[Kelpie]

What's the current thinking on the catenary effect?

This month's YM- article by Vyv Cox describing how catenary ceases to have sufficient shock absorbing effect in winds above about f6.

 

[dom]

What's the current thinking on the catenary effect?

Vyv Cox weighs in (terrible joke!) on this topic in this month's YM. Basically he agrees that for sailing yachts and mobos, the catenary effect is entirely non-existent in above a F5/6

 

[Neeves]

As the article will not reach me till july or August I'll base my comment on the briefs in #47 and 48. I would agree with Vyv and if you extrapolate then the benefits of chain weight lose relevance and the critical issue is choosing a chain strong enough. In fact if weight is irrelevant then the lightest chain possible, of commensurate strength (with snubbers) is the logical conclusion.

It has to be mentioned, I obviously do not know if its in the article, but the idea, of light chain, has been used by Dashew for decades but his philosophy is light chain and oversized anchors (I have at the back of my mind he is not totally enamoured of snubbers). I disagree with the oversize anchor - and have seen no evidence to support the idea, when asked here forum members with modern anchors (whether they had recommended sized anchors, or slightly smaller) had no examples of their anchors dragging.

Jonathan

 

[vyv_cox]

It has to be mentioned, I obviously do not know if its in the article, but the idea, of light chain, has been used by Dashew for decades but his philosophy is light chain and oversized anchors (I have at the back of my mind he is not totally enamoured of snubbers). I disagree with the oversize anchor - and have seen no evidence to support the idea, when asked here forum members with modern anchors (whether they had recommended sized anchors, or slightly smaller) had no examples of their anchors dragging.

Jonathan

I didn't mention the Dashew thinking in my piece but I did discuss the Alain Poireaud one, based on his collaboration with Alain Fraysse. AP reckoned that heavy-ish chain of length about the depth of the water and the rest rope was just right. There are disadvantages of course, which I discuss, but if you are on your own in a big anchorage no problem at all.

I do agree with you about oversize anchors, I have yet to hear any evidence that a correctly sized concave anchor in a half reasonable seabed has dragged. The Evans Starzinger work in Chile says otherwise but I think that anchoring on coral presents difficulties all of its own. People in South Wales seem to anchor regularly on shingle and pebbles, where I am told an oversized anchor is a good investment, but these are both exceptions.

 

[NormanS]

Well I'm an engineer, and I still believe in the benefits of catenary, obtained by using heavy chain. However, I have a relatively heavy boat, and a few extra kilos of chain are neither here nor there for me. Catenary is of course no use if you anchor in very shallow water, and heavy chain is a no-no with a light-displacement, weight- conscious boat.

If I am anchoring, expecting a blow, I'll obviously choose a sheltered spot, but I don't choose shallow water. I'll also rig an anchor sail, which stops the boat from yawing around. This yawing, particularly if the chain closest to the anchor is lifting off the bottom, means that the anchor is being pulled in different directions each time that the boat sheers off from side to side, tending to upset the anchor's grip. I'm fortunate in that I usually sail in relatively unfrequented waters, so am normally unrestricted in the scope that I can use.

I can quite understand that for those with light-displacement boats, sailing in busy areas, the above is not relevant, but to state boldly that catenary has no effect is not correct.

 

[GHA]

I do agree with you about oversize anchors, I have yet to hear any evidence that a correctly sized concave anchor in a half reasonable seabed has dragged. The Evans Starzinger work in Chile says otherwise but I think that anchoring on coral presents difficulties all of its own. People in South Wales seem to anchor regularly on shingle and pebbles, where I am told an oversized anchor is a good investment, but these are both exceptions.

I think the oversize argument mainly applies to long distance worldgurdler cruisers, 99% of the time not necessary but once in a while very welcome.

 

[JumbleDuck]

I do agree with you about oversize anchors, I have yet to hear any evidence that a correctly sized concave anchor in a half reasonable seabed has dragged.

That's a tad no-true-Scotsman, I fear.

It interests me that new generation anchor devotees almost always seem to go for ones as heavy as the older types n order to get more holding power, rather than going for the same holding power with less weight. Bearing in mind the busted flush status of the catenary effect, I'm seriously tempted to replace my 25lb CQR + 8mm chain with something newer and lighter (FX-7?) and rope.

 

[doug748]

.........., but to state boldly that catenary has no effect is not correct.

I can't see that people do say that. The other case is also true, I don't feel that anyone seriously thought that catenary worked without limit.
So, when a gale rages at sea, and you have 25kts, or more, through your anchorage the chain will snatch. I doubt you could find anyone to argue with that, or the idea that up to these limits the catenary is doing it's job fine.
A lot of forum dissent seems to hinge on opposition to extreme views which no one really holds

 

[vyv_cox]

It interests me that new generation anchor devotees almost always seem to go for ones as heavy as the older types n order to get more holding power, rather than going for the same holding power with less weight. Bearing in mind the busted flush status of the catenary effect, I'm seriously tempted to replace my 25lb CQR + 8mm chain with something newer and lighter (FX-7?) and rope.

Having used a Delta for 20 years with very few problems I bought the recommended Rocna that is actually 1 kg lighter. If the anchor tests are to be believed the Delta will typically hold rather more than half the force that a Rocna/Manson/Spade will. It is easy to look at the numbers without relating them to actuality. For the size of mine a Rocna will hold 2 tons and the Delta more than 1 ton, according to the YM/Sail magazine/West Marine test results. Even 1 ton is an enormous pull, far more than the majority of us will ever see in an anchoring situation. When younger I regularly pulled my boat up to the anchor in winds of force 5-6 and I feel certain that even in the full flush of youth (well, about 40) I could not pull 1 ton, never mind 2 tons. I doubt it was ever much more than 60 kg.

 

[NormanS]

I can't see that people do say that. The other case is also true, I don't feel that anyone seriously thought that catenary worked without limit.
So, when a gale rages at sea, and you have 25kts, or more, through your anchorage the chain will snatch. I doubt you could find anyone to argue with that, or the idea that up to these limits the catenary is doing it's job fine.
A lot of forum dissent seems to hinge on opposition to extreme views which no one really holds

Well, when I have 25 knots of wind, I don't consider it to be a gale, and my chain won't snatch. But even in a real gale, by using reasonably heavy chain, reasonably deep water, and if I think it warrants it, an anchor sail, my chain never snatches anyway. I am, however, referring to anchorages which are sheltered from the sea. I have no experience of anchoring out in open water, nor do I wish to get any.

 

[doug748]

In which case we can substitute "may" for "will" in line 4.

The point I am making is that catenary effect will run out at some stage and at that point we make alternative arrangements. As we always did.

 

[dom]

That's a tad no-true-Scotsman, I fear.

It interests me that new generation anchor devotees almost always seem to go for ones as heavy as the older types n order to get more holding power, rather than going for the same holding power with less weight. Bearing in mind the busted flush status of the catenary effect, I'm seriously tempted to replace my 25lb CQR + 8mm chain with something newer and lighter (FX-7?) and rope.

Just quickly - a few years ago Spade recommended I purchase a 20kg anchor (I can still manually lift that off my single bow roller) - boat is just under 50'. At the time I told them that I'd be back and purchase a 30kg for more serious work. The French dealer said he wasn't holding his breath.

Just before Christmas I gave this anchor a bash in the Solent (45kts ish + 1.25m fairly short waves). No technique; just let the boat drift backwards (prob c. 2kts), lob out the chain on a short 3x scope and bang the boat is anchored in the mud. Try the same technique in sand and it works after a little scrape on the bottom; only on pebbles does one need the touchy feely building the pressure up malarkey. Mind, on grit/pebbles when it comes to setting off after say an overnight, the thing is invariably stuck and takes a good old opposite direction yank to release.

No idea about the other new gens, but yes defo go lighter with these things, or you'll needlessly lighten your wallet and squash your fingers!

 

[JumbleDuck]

Having used a Delta for 20 years with very few problems I bought the recommended Rocna that is actually 1 kg lighter. If the anchor tests are to be believed the Delta will typically hold rather more than half the force that a Rocna/Manson/Spade will. It is easy to look at the numbers without relating them to actuality. For the size of mine a Rocna will hold 2 tons and the Delta more than 1 ton, according to the YM/Sail magazine/West Marine test results. Even 1 ton is an enormous pull, far more than the majority of us will ever see in an anchoring situation.

Serious question: why did you not save money, weight and effort by buying a 1 ton Rocna?

 

[Neeves]

The Classification Societies allow a SHHP, say Supreme, anchor to be, I think its, 30% lighter than a HHP anchor, say Delta. Its been said before, doubling weight does not double hold. To double hold, of say a Supreme, you would need to triple weight.

We use a 15kg steel anchor (SHHP), our cat has the windage of a 45' yacht, a Bav 45 to be precise. We weigh in at 7t, I guess the Bav might be 13t. We have discarded the steel anchor and are using a 8kg alloy model, same dimensions (except for weight) as the steel version. Our 15kg steel replaced a (HHP) 22kg CQR copy, made by Manson. We used to regaularly drag with the CQR copy, after almost 10 years we have not yet dragged with the SHHP model. We now use 6mm chain.

I need to qualify my comment on catenary.

I think if you have a 45' yacht and add 200m of 12mm chain - then catenary will work to higher windspeeds than Vyv's F6. But having 200m of 12mm chain in the bow of a Bav 45 is unrealistic - which would be true for most people. I have not seen a heavy displacement yacht at a boat show for decades - most of us have AWBs, they are readily available, there are lots to choose from, in general they sail well, they are easy to maintain, very importantly our wives like them, and they are easier to sell. I don't know how many AWBs are commissioned every year but the numbers over the last 3 (?) decades must be huge. So pandering to the masses, of which I am one - catenary is a con. Big chain needs a big locker, big windlass (heavy reinforcing), big current draw, big wallet - and reduces the seakeeping ability of anything but a really heavy displacement yacht. The same snubbing effect of catenary can be achieved at any wind speed with a 10m/15m snubber - the only time you miss out is in drifting conditions.

There are always exceptions (for example racing yachts) - it is impossible to cater for all of them. If you have an unusual yacht, in todays terms, you will have unusual solutions.

Jonathan