What weight NG anchor for a 20ft yacht?

[thinwater]

A good question, and I appreciate Glenlivet's thoughts on this too. My anchoring is not really tested except on local cruises in good weather, and I experienced no problem - but I wouldn't expect to given the conditions. As the Scotland trip is a big thing for me I'm happy to invest in the right anchor to reduce the risks, and to reduce the risk of sleepless nights next summer.

I should add that I have no experience with kelp and will defer to others.

 

[chriss999]

Ignoring whether it is better or not why would a 6 kg Rocna anchor be lighter to handle than a 6kg Kobra (which Plastimo say it suitable for an 8 m boat)
https://www.plastimo.com/en/ancre-kobra-9988.html

Hmm. The version I've got is different! My version is prettier but recommends heavier anchors.
https://www.plastimo.com/media/catalog/product/files/t/h/the_basic_rules.pdf
I wonder if Plastimo marketing department were fed different data.

 

[Stemar]

If the budget is an important consideration, a genuine Delta can be had for less than £100. I'd go for the 6Kg for your boat, as I have a 10Kg on my Snapdragon 24, and am regularly amused to see the same anchor on 30+ footers. I'm sure it's fine for them, but I like to sleep well a'night Over the years, I've spent many a night at anchor, though never in more than a good F7 and have never dragged. You could save weight in the bow by halving your chain and adding, say 40m (or more) of rope. This would allow more scope or allow you to add a bit of elasticity as well as giving the option to anchor in deeper water if necessary.

 

[jordanbasset]

Hmm. The version I've got is different! My version is prettier but recommends heavier anchors.
https://www.plastimo.com/media/catalog/product/files/t/h/the_basic_rules.pdf
I wonder if Plastimo marketing department were fed different data.

From my reading of that link it is giving generic advice for anchors, not specifically a Kobra anchor, indeed it is more than suggesting you do not need such a big anchor if you choose a Kobra saying

' Voile Magazine and Moteur Boat Magazine gave clear evidence that ”a 6 kg Kobra anchor held a 600 kg traction load, in a mixed sand-mud seabed”, which corresponds approx. to the traction exerted by a 42-knot wind on a 9 m boat, where a 12 kg anchor is traditionally recommended.'

But don't wish to Labour the point and the Rocna is a very good anchor, not quite up to a Kobra but still very good:-}

 

[bitbaltic]

From my reading of that link it is giving generic advice for anchors, not specifically a Kobra anchor, indeed it is more than suggesting you do not need such a big anchor if you choose a Kobra saying

' Voile Magazine and Moteur Boat Magazine gave clear evidence that ”a 6 kg Kobra anchor held a 600 kg traction load, in a mixed sand-mud seabed”, which corresponds approx. to the traction exerted by a 42-knot wind on a 9 m boat, where a 12 kg anchor is traditionally recommended.'

Reassuring as our best bower is a 6kg delta on a 30ft boat (but she is a light 30 footer). Never had an issue with it failing to set and it’s easy to haul up. But we only do lunch-hook anchoring, and it’s the biggest anchor that would fit on top of 30m chain and 50m warp in the woefully small anchor locker.

I have a 12kg Kobra at the bottom of the Lazarette which I bought a) because it was on a great deal from that Bristol chandlery that Cactus took over just before they disappeared and b) because I figured it would be a better overnight hook. But as a family with kids we have never anchored overnight in the Bristol Channel.

Don’t think there’s any real design differences between small kobras and small deltas.

Suggest the OP picks up a 6kg version of either as cheaply as poss for a quite small boat and doesn’t worry about it.

 

[blan321]

+1 choose an anchor good for weed, we found this a problem 30 yrs ago with CQR in west coast Scotland anchorages

 

[chriss999]

From my reading of that link it is giving generic advice for anchors, not specifically a Kobra anchor, indeed it is more than suggesting you do not need such a big anchor if you choose a Kobra saying

' Voile Magazine and Moteur Boat Magazine gave clear evidence that ”a 6 kg Kobra anchor held a 600 kg traction load, in a mixed sand-mud seabed”, which corresponds approx. to the traction exerted by a 42-knot wind on a 9 m boat, where a 12 kg anchor is traditionally recommended.'

But don't wish to Labour the point and the Rocna is a very good anchor, not quite up to a Kobra but still very good:-}

Good point about the dodgy sizing - that came to me from a supplier in response to my Kobra query. I’ll bat it back. Thank you for that!

I’m trying to keep this thread on weights rather than anchor brands, but thank you to all posters for your invaluable advice.

 

[Kukri]

It’s really a question of weight, if it’s a matter of getting through weed. Small anchors just won’t work.

You can buy a secondhand genuine CQR for much less money and it will do fine.

 

[zoidberg]

It’s really a question of weight, if it’s a matter of getting through weed. Small anchors just won’t work.

You can buy a secondhand genuine CQR for much less money and it will do fine.

You can BORROW the genuine adequate CQR I have here FOC. I will not be needing it. You could then with advantage cut your chain in half, and add 2 x 30 metres of cheap ( tough as old boots ) polysteel rope from a fishing outlet ( there's one above Brixham, for starters ). That setup'll do nicely.

I drive through Devon quite frequently.... like tomorrow!

 

[chriss999]

You can BORROW the genuine adequate CQR I have here FOC. I will not be needing it. You could then with advantage cut your chain in half, and add 2 x 30 metres of cheap ( tough as old boots ) polysteel rope from a fishing outlet ( there's one above Brixham, for starters ). That setup'll do nicely.

I drive through Devon quite frequently.... like tomorrow!

Zoidberg thank you for that. I will take your advice on chain, rope and anchor weight. But I won’t take your CQR, though. Thank you for the offer, but I do fancy (oops almost wrote ‘need’) a new anchor as i’ve not got a spare.

 

[Bodach na mara]

I have spent a lot of time on the foredeck with a boathook removing kelp from anchors after anchoring in the lochs of western Scotland. I have also dragged CQRs (genuine), CQR types, Halls stockless (useless in small sizes), Danforth, Brittany, and Delta. Some of the, ahem, "older" sailors around here say that nothing holds in kelp like a fisherman, and it is easier to clean as well, but although I have one I have never tried it. Well, I never know that I am into Kelp until either we drag or I get the anchor near the surface with about 100 kg of the stuff completely hiding it.

On the chain topic, lots of people will go on about all the deep anchorages up here. Like Tobermory, where you will be lucky if you can find a spot to anchor with less depth than 25 metres and swinging room will not be enough to use a rope rode. But if you are bilge keeled and do not mind possibly taking the ground at the bottom of the tide, then there are often large areas in anchorages in bits where you will get a lot of people rowing past to tell you that it is too shallow. I prefer anchoring in less than 5 metres at mid tide and often have interesting conversations with people in rowing boats as local bilge-keel boats like mine are relatively rare.

 

[Neeves]

I don't see the point of upgrading an anchor from an older design, Delta, Bruce and CQR then buying a bigger new gen and keeping the old anchor. If the old anchor was inadequate dump it. If the new anchor is all it is cracked up to be - you should not need bigger one. If the old one is perfectly good enough do not buy a new anchor - or in this case, buy a Fortress/Guardian (often available in the UK, I understand, on eBay) as second anchor.

I have tested the Kobra - it offers excellent hold, sets quickly and looks nothing like a Delta. I'm not keen on its thin shank - but plenty here use them without issue. I have tested the others on your list, they are all good anchors, including the lessor known Knox (but they all have weaknesses). We carry as 'standard' an Excel (Anchor Right from Australia - so not possible for your budget, unless you visit - and then it would fit in luggage), Spade and 2 x Fortress (a bigger one for thin mud and a smaller one). All our anchor are alloy, 8kg, and we use 6mm chain. Tasmania is very similar to Scotland's west coast - and has lots of kelp (which we avoid).



Chris, thank you for listing prices, I can understand why a Rocna might stand out. A Kobra would stand out further!

I might have missed it but you have not defined the size of your chain - if its 8mm it is far to heavy and the weight of the anchor is insignificant in comparison. If it is 8mm and you want to save weight - get some 6mm it will be more than strong enough - and your back will love you for the change. If you had 6mm you could store it in a bag, or my favourite - a milk crate. And store down below. Storing 40m (I recall that is the length you carry) of 8mm down below (or in the bow of a small yacht) is a nightmare and if the depths are 20m - book the chiropractor now!

Because of the possibility of weed, other than kelp, and I don't know how big an issue weed might be I'd tend to favour an anchor with a ballasted toe, Spade/Kobra. Its not about surface area, in one respect the opposite - its about getting through the weed (and the narrow profile of the Kobra is ideal. Anything small with a roll bar is going to struggle in weed. Possibly someone with more intimate knowledge can comment on weed in the west of Scotland. I don't think any anchor of a small size, with no disrespect, will handle kelp well.

No anchor is perfect, some anchors work better in some seabeds and not well in others - which is why I suggest your other anchor(s) should be of a different designs. If you were to buy a Kobra - I would suggest dumping the CQR (copy?) as they are more similar, than different.

I think someone said that a Kobra could be bought for around stg65 ?, you could buy a Supreme and Kobra for the price of that Rocna??!! I doubt anyone can differentiate between the performance of similarly weighted Rocna and Supreme.

Mixed rode - go on 'local' advice - but if the anchorage are deep 40m might not be adequate by itself.



Jonathan

 

[noelex]

I am looking to buy a new anchor and am confused by the weight recommendations given by different manufacturers.

It is confusing, Chris.

We have the strange situation that manufacturers of better anchors generally recommend larger sizes than manufacturers of less capable designs. Unfortunately, I think anchor sizes are influenced by marketing. People assume that if a smaller anchor is recommended, the design must be superior to an alternative model where a larger one is needed for their sized boat. A smaller recommended size also helps sell the anchor to boat builders where very large sales volume can be generated. Not only does the supplied anchor need to be smaller, but all the associated equipment such as anchor winches etc are then less expensive.

An alternative approach to the manufacturers’ tables, is to fit the largest anchor you (both the boat and crew) can comfortably manage. I think this is good approach for a cruising boat that is regularly anchoring overnight. Your experience with the 14.75 lb CQR should give you some idea if more weight is manageable, but bear in mind that all the better designs will have a much larger fluke area than the same weight CQR so they will be physically larger, although at least modern anchors do not bite fingers like the hinged CQR .

The Mantus anchor is a good option. Its long thin fluke gives it very good weed performance, which is often the Achilles heel of modern designs. It is an excellent general purpose anchor and is an ideal choice for the diverse and sometimes tricky substrates in the West coast of Scotland.

 

[Neeves]

It is confusing, Chris.


The Mantus anchor is a good option. Its long thin fluke gives it very good weed performance, which is often the Achilles heel of modern designs. It is an excellent general purpose anchor and is an ideal choice for the diverse and sometimes tricky substrates in the West coast of Scotland.

You have experience of using a Mantus, particularly a small one in weed (and know of the diverse and sometimes tricky substrates) on the west coast of Scotland?

I am very impressed.


Recent tests suggest that to develop the hold of a 6kg Rocna (in sand) you will need a 12kg Mantus. Results will be published in one of the next publications of Practical Sailor. No tests have been conducted in weed and I would hesitate to comment, at all - and defer to Noelex' practical experience in west coast Scot's waters. Additionally a recent description on performance of a Mantus, I think around 12-15kg, by a, member here, lives on his yacht in the Med for 6 month of the year, suggests they take a long distance to set, 3m was quoted (where most NG anchors, Rocna, Spade, Supreme in a variety of independent tests on 12/15kg anchors suggest they set in about a 'shank' length, so maybe 1m).

Jonathan

 

[noelex]

You have experience of using a Mantus, particularly a small one in weed (and know of the diverse and sometimes tricky substrates) on the west coast of Scotland?

I am very impressed.

Thanks for the compliment .

I guess you are trying to make the point that a small anchor (even assuming it is an appropriate size for the boat) is not likely to do as well as a large anchor of an identical design in weed.

I agree. Most anchor designs, in most substrates, scale reasonably, so a small anchor on a small boat will have similar performance to a large anchor on a large boat, but the relationship tends to break down in heavy weed. The weed does not change size as you change boat size, and a smaller anchor on a smaller boat will tend to have a tougher time cutting into weed.

There are some compensations. Small vessels such as the OP’s yacht can often get into shallower, more protected anchorages, or locations within an anchorage. However, in the OP’s position, with a small vessel, that naturally needs a small anchor, if intending to cruise the west coast of Scotland I would be trying to select an anchor with good all round performance, with particular emphasis on weed performance.

 

[Glenlivet]

‘West coast of Scotland’ is pretty general. My guess is that the OP is intending to cruise the Clyde, loads of very safe anchorages and also marinas to run to if the going gets tough. I still think the CQR is more than adequate for this cruising ground (been there, done it), the OP did specifically use the word ‘want’ rather than ‘need’ though when talking about his proposed new toy :encouragement:

 

[MM5AHO]

For information about a 6.5kg Knox. They will be on special at the Kip boatshow. A significant discount, that size only. See you at the show!

Declaration of interest: I sell Knox anchors.

 

[seaangler23]

Our cqr limited our west coast trip this year, had no faith in it after its failed to reset after a couple of wind shifts and long nights in anchor watch, noticed rocnas we’re plentiful in marinas up that way so that’s what I’m going for

 

[chriss999]

‘West coast of Scotland’ is pretty general. My guess is that the OP is intending to cruise the Clyde, loads of very safe anchorages and also marinas to run to if the going gets tough. I still think the CQR is more than adequate for this cruising ground (been there, done it), the OP did specifically use the word ‘want’ rather than ‘need’ though when talking about his proposed new toy :encouragement:

Want, need, what is the difference? I want it so I need it!
Actually I do need a second anchor, and I would prefer to spend a few £ and get one best suited for the conditions.
When I was 16 or 17 in my navy cadet group we spent a happy week in an old MFV steaming around the Clyde. Down to Ailsa Craig, up around the Kyle of Bute etc, round Arran etc, and it was so lovely that I've always wanted to go back. I envy you Glenlivet in your cruising ground. Now I will get a chance at the age of 60, in my own boat.

But I do hope to go further as well, up to Islay, Jura, Skye and really as far as I can get in the summer, next year. So I'm thinking of doing quite a bit of anchoring, if all goes well.

 

[Neeves]

Chris,

You will be doing this already - I'd not rush off and buy, there are going to be deals, like Knox Anchor (there is one in America just now for Rocnas), there are going to be people offloading anchors on eBay - and you are not going to need an anchor, (or the new anchors) till next year. Boat shows are obviously good hunting ground. If you know anyone who visits America then Fortress are much cheaper there - and are so light fit in a suitcase. We bought our Kobra, way back, from the chandler at Preston and put it in our suitcase (but you do need to plan or you will be well overweight). I'd not buy one through a chandler there, in the US, as they have forgotten about 'normal' post and want to send everything by courier - and its then too expensive.

I'd be pressing Geoff of KA to be a bit more specific. A minor advantage of buying from Geoff, other than you would become the proud owner of a decent anchor, he will also offer matching components for your rode (as he appears to offer a complete package). Its a good anchor, exceptionally well made, bullet proof, sets quickly and holds well in the seabeds we have tried, sand and mud. It will cope with thin ribbon grass - but not dense ribbon grass (and weed is going to be an issue for any small anchor being set with a small motor). For weed, non roll bar, Kobra, Spade or Excel. For sand, mud and especially thin mud - nothing will compete with a similarly sized Fortress. Fortress can clog, small stones, shell, weed and jam, jamb?? the fluke mechanism - so you need to consider wind shifts.

Declaration of no interest in any anchors - anchor are compromise, there is no perfect anchor.

Jonathan