Choosing The Right Anchor

[Alan de Enfield]

NB's that have anchors tend to have anchors designed for 'ease of stowing' rather than anchoring performance. whereas, I would suggest' a NB that needs an anchor needs one that is guaranteed to 'work' so as to minimise the risk of going over weirs, etc.

 

The typical NB anchor is a 'Danforth' - these are rarely tested or compared as their performance is so poor.

 

The modern generation of anchors (Mantus, Manson, & Rocna) far, far outperform the Danforth.

 

 

If you intend to buy an anchor, buy one that will work - not the one that fits into your bow locker.

[GUMPY]

There have been some spectacular failures of one anchor in that list........

IIRC It happened about the time the company changed hands....

 

ETA Danforth is hard to beat when setting in mud....

Edited January 19, 2017 by Loddon

[mross]

Can you advise who did this testing?

 

I found more tests here http://www.petersmith.net.nz/boat-anchors/independent-performance-testing.php

 

I always seem to find good things in Oz and NZ!

Edited January 19, 2017 by mross

[churchward]

I Like to have an anchor that sinks!

[Sea Dog]

The thing about anchor tests, most boater's views, maritime advice and other sources of information is that it's almost all based around anchoring a vessel as a routine means of (for want of a better word) mooring. A yacht or motorboat has a controlled deployment of its anchor, requiring it to hold in various bottoms as the tide, wind and current work against it and then release nicely when it's time to weigh. Narrowboats need an anchor only as an emergency brake, to chuck and hope it stops us and holds as we head down river at a similar rate to the flow after losing power or steering. Retrieval for us is a bonus.

 

There's a world of difference between the two requirements, but most advice is derived from the former rather than the latter. There is some generally accepted wisdom, but my point is that the subject is not as clear as you might expect whatever you read or hear needs to be tempered with the application in mind.

[Alan de Enfield]

Can you advise who did this testing?

 

I found more tests here http://www.petersmith.net.nz/boat-anchors/independent-performance-testing.php

 

I always seem to find good things in Oz and NZ!

 

I believe it was part of a series of tests undertaken by Motor Boat Monthly -

Here is another review in which they did not bother to test the Danforth.

 

MBM_Rightpick Anchor Selection.pdf

 

They didn't test the Mantus, but did test the Rocna and the Manson (2 of the 'other' latest generation anchors).

I understand that Lloyds Shipping had to add an extra category of 'certification' called SHHP (Super High Holding Power) to accommodate these latest designs which are so much better than the HHP (High Holding Power) of previous designs, such as the Bruce.

 

Anchors can also be tested against others with the desired standard; should they hold at least the same load in comparison, this then is accepted as equivalent. Its designer confident that superior performance would be displayed, the Rocna anchor was tested by RINA against a New Zealand built copy which already had SHHP classification from Lloyd’s Register. In clay, the Rocna 25 recorded pulls at an average of 6,250 kgf, while the larger Manson Supreme 27 kg managed an average of 4,665 kgf; in soft mud, the Rocna averaged 635 kgf versus the copy’s 560 kgf. In the same locations stockless anchors four times the weight were recording pulls a quarter of the Rocna’s results. Unfortunately such test results are rarely published so inspecting the basis of classification can be difficult.

 

The anchor weight is not always the most critical guide to performance.

 

As can be seen on the MBM tests a much lighter (22lb) 'Fortress' anchor outperformed many of the heavy weights (38-39lb) under test

[mross]

Has a narrowboat ever been swept over a weir? I used to live opposite Fladbury weir. The locals used to ride bicycles across the weir and it was normally about 6 to 9 inches deep; I don't think that would necessarily topple a narrowboat but it would certainly trap it.

 

I will certainly have a look at my anchor and see if it is fit for purpose. I have a couple of mud anchors but have not had any need to use them. Thanks for starting this thread.

[Alan de Enfield]

Has a narrowboat ever been swept over a weir?

 

Yes - quite a lot.

 

There was one I know of on the Trent last year.

Caught on the 'dolphins', wife fell overboard, husband grabbed her, couldn't turn off the engine, prop still going round, had to let her go to avoid her getting cut-up by the prop.

Wife went over the weir, he stopped the engine, NB 'rolled under' the Dolphins, he was swept overboard.

 

Boat righted, went into the trees, stern rails, top-box etc all smashed, husband and wife survived, boat recovered.

 

C&RT provided a skipper' to get the boat into our marina as they were a bit 'frit' of going alone.

 

Year before - we pulled a boat 'off the wei'r on the Trent - fortunately his anchor had set about 50 yards before the weir, but it was a brown-trousers job.

 

Don't forget that in times of high water, boats in a hurry would 'shoot the weirs' to get back to reload quicker - waiting for the lock was time, time was money. (and they were a lot bigger and deeper draughted than a NB)

[Martin Megson]

Has a narrowboat ever been swept over a weir? I used to live opposite Fladbury weir. The locals used to ride bicycles across the weir and it was normally about 6 to 9 inches deep; I don't think that would necessarily topple a narrowboat but it would certainly trap it.

 

I will certainly have a look at my anchor and see if it is fit for purpose. I have a couple of mud anchors but have not had any need to use them. Thanks for starting this thread.

 

The boat rarely goes "over" the weir as there is insufficient water depth. Instead the boat can be pinned against the weir or bollards and then get rolled by the water pressure. Has happened many times on rivers such as the Trent and Nene.

[mross]

 

The boat rarely goes "over" the weir as there is insufficient water depth. Instead the boat can be pinned against the weir or bollards and then get rolled by the water pressure. Has happened many times on rivers such as the Trent and Nene.

Well, I would still class that as going over. On its side or not.

[Iain_S]

The Mantus appears suspiciously good in the above chart, especially on hard ground!

 

The Danforth is fairly good in soft ground, as are other "plough" or "plate" types, and so would suit the lower reaches of most rivers, at least when out of the current.

 

"Hard Soils" is a bit of a variable feast, ranging from hard sand through boulders to relatively smooth rock. The most challenging use of an anchor I've done was in the upper reaches of the River Forth a few years ago, when a small flotilla went to Stirling. The "ground" is notoriously difficult, being rock or gravel, and I don't think any of the assortment of anchors carried were without problems. Gamebird has a Fortress FX7, and this took three tries to get it set. Once set, however, it managed to re-set itself according to the tidal flow without any bother. I did attempt to hold the boat pointing the same way by using a mud weight from the stern, but this was a total failure. The mud weight did absolutely nothing. A second anchor, properly set, would have done the job.

 

Although, as said above, the anchor requirements for a narrowboat and a vessel which habitually deploys its anchor as a parking brake are different. The narrowboat actually needs a more reliable system, IMO, as if used in anger, it's a last resort and has to work, while the boat deploying its anchor at leisure can take their time, make several attempts if necessary, or move to a better location.

 

Almost as important as the anchor is the chain, which to my mind should be oversized from the strength aspect, to give more weight, and encourage the anchor to bite sooner and deeper.

[blackrose]

NB's that have anchors tend to have anchors designed for 'ease of stowing' rather than anchoring performance. whereas, I would suggest' a NB that needs an anchor needs one that is guaranteed to 'work' so as to minimise the risk of going over weirs, etc.

 

The typical NB anchor is a 'Danforth' - these are rarely tested or compared as their performance is so poor.

 

The modern generation of anchors (Mantus, Manson, & Rocna) far, far outperform the Danforth.

 

 

If you intend to buy an anchor, buy one that will work - not the one that fits into your bow locker.

That table is missing quite a lot of anchor types and seems to be focused on plough anchors. Mine is a Stockless anchor.

[Alan de Enfield]

That table is missing quite a lot of anchor types and seems to be focused on plough anchors. Mine is a Stockless anchor.

 

Each to their own - but as quoted above :

 

In the same locations stockless anchors four times the weight were recording pulls a quarter of the Rocna’s results.

 

Stockless anchors are consistently out performed by modern variants. (by a factor of 16 times in the case of the Rocna)

 

As Ian says in post #11 - for a canal / river boat the anchor is the last chance and needs to work 1st time - everytime. For a sea going / estuary boat, if it doesn't set immediately it doesn't matter and you can just re-set it.

 

Recently our 20Kg Brittany anchor ( a fairly good one but which we are currently replacing with a 30kg Mantus) dragged about 6 or 7 times during the night, the anchor alarm sounded and we just re-deployed eventually getting 10x water depth (in 6 foot of water) with 100% chain.

 

Maybe it is time to review your anchor and the requirements you have for it.

[Alan de Enfield]

That table is missing quite a lot of anchor types and seems to be focused on plough anchors. Mine is a Stockless anchor.

 

These days it seems no one is using anything other than 'plough' type anchors - another series of tests from "Yachting Monthly"

 

Yachting Monthly -Anchor Test Nov09.pdf

[Dalesman]

Has anyone anchored in Tixall Wide..?

[Naughty Cal]

NB's that have anchors tend to have anchors designed for 'ease of stowing' rather than anchoring performance. whereas, I would suggest' a NB that needs an anchor needs one that is guaranteed to 'work' so as to minimise the risk of going over weirs, etc.

 

The typical NB anchor is a 'Danforth' - these are rarely tested or compared as their performance is so poor.

 

The modern generation of anchors (Mantus, Manson, & Rocna) far, far outperform the Danforth.

 

 

If you intend to buy an anchor, buy one that will work - not the one that fits into your bow locker.

Interestingly the Delta anchor that we have doesn't fair too well when compared with others on the chart, yet we have never had a problem with it setting and holding in a variety of bottom conditions and sea conditions.

 

This could well be though because it is over sized for the boat, 10kg rather then the 6kg recommended, and we are also on all chain and tend to let out more scope then the minimum recommended amount.

 

You have reminded me that we need to let it all out at some point before our summer trip and check the condition of the shackle, chain and webbing strap.

 

Another job for the list.

[Silebyman]

It seems that different anchors setting performance changes dependant on what the bottom is ( sand, mud, rocks etc).

 

Is there anything around that specifies what the bottom is on rivers most NB's are likely to encounter,

 

Same does for depth of river when working out chain/rope lengths. I know there are rules of thumb around such as 'Chain = x times river depth' etc, but unless you know the average depth of river they are not a lot of use.

 

I've been trying to work out what I need for the non-tidal Trent for a while, but depth and bottom type has eluded me

[Alan de Enfield]

 

 

I've been trying to work out what I need for the non-tidal Trent for a while, but depth and bottom type has eluded me

 

Majority of the Trent is Sand /. Gravel / Shell

Depth varies between 6 feet and 20 feet, but in 'flood conditions' can be many feet higher.

 

Ideally a minimum of 60 foot of 100% chain - preferably 100 foot.

[Silebyman]

Thanks for that - helpful..

[Alan de Enfield]

Thanks for that - helpful..

 

Next question - Anchor type & size.

 

It us interesting that (I think) all of the anchor manufacturers suggest that the 'boat weight' is the deciding factor in anchor weight choice - given that there is a length recommendation and a 'weight' recommendation - go for the 'highest' (normally the weight)

 

 

The 'Ultra' anchor is one of the 'higher performance' anchors being considerably superior to the likes of the Danforth and yet for a 16 ton boat they suggest 21kg, and for a 24 ton boat suggest 27kgs.

 

Many 'River Boaters' will say I cannot lift a 20 / 27kg anchor so just have a 10kg one - pretty much a waste of time and gives a false sense of security.

 

If the anchor has 'saved you and your boat' then the last thing to worry about is the recovery of the anchor - once your boat is 'sorted' you can if need be, tow the anchor out 'backwards' or even just 'abandon it' - it may have saved your life and saved a £X,XXX boat so the loss of 'a couple of hundred pounds' is insignificant.

 

Don't cut corners on safety.

[RD1]

When we were on the Norfolk Broads, the general anchor used by broads skippers was a mud weight, some call it a mud anchor, basically a tapered cast iron weight, weighing up to 25 kg, or 56lb, as often cast iron scale weights were regularly used as well. For our Viking 23, we found a 28 lb cast iron weight was adequate, but if the wind got up, I could double that, and I could add more.

 

However, on the Thames, which can have considerable flow, especially near the weirs, I decided to blow the dust off a 7 kg danforth type anchor that I had inherited from my father. I added 6m of chain, and I keep this close to hand in the cockpit, ready to deploy, as we have a rope tied off to the bow that reaches the cockpit, and a depth sounder so we can deploy the correct amount of line.

 

My first thought was... how was I going to retrieve it, then as I read various comments on here, that supported my own belief that the anchor is expendable, when you consider the consequences leading up to it's use in anger. We are not going to be casual mooring in a tidal weir stream. If it has to be abandoned, we could buoy it with one of the large fenders and retreive later.

I have also made up a loop of chain on a line, that I could wobble down the anchor warp and anchor shaft, and attempt to pull the anchor out backwards, never tried this though... but dib dib dib, be prepared lol

Edited January 20, 2017 by RD1

[Naughty Cal]

This does rather beg the next question of how many people actually know how to set an anchor so that it works?

[Alan de Enfield]

............7 kg danforth type anchor

 

 

Probably just about the acceptable minimum size for a 2 tonne boat - ideally get some more chain to 'add weight'.

This does rather beg the next question of how many people actually know how to set an anchor so that it works?

 

Throw it overboard, pile all of the chain on top of it and let it sort itself out ????

[RD1]

This does rather beg the next question of how many people actually know how to set an anchor so that it works?

To be fair, I read it up on the internet, and I will be honest, it might have got thrown overboard like a broad's mud weight, had I not read up on it.

This what is in my mind at the moment...

Lower it rather than throw the anchor.

Be aware of the river flow, let out the chain/line at a similar speed to the flow rate so no chain or line fouls the anchor, when deployed, gently reverse back till it grabs. But if your engine has failed, probably need some slack in the line so the boat snatches it.

 

Now I know this is partly the jist of it, but I would welcome any advice or a link to a suitable website.

 

We need something simple, we don't want an instruction sheet to read. The action of dropping the anchor has to be instinctive bearing in mind, the stress we could be under when we have to deploy it.

Edited January 20, 2017 by RD1

[Naughty Cal]

 

Next question - Anchor type & size.

 

It us interesting that (I think) all of the anchor manufacturers suggest that the 'boat weight' is the deciding factor in anchor weight choice - given that there is a length recommendation and a 'weight' recommendation - go for the 'highest' (normally the weight)

 

Ultra Anchor Holding Sizes.png

 

The 'Ultra' anchor is one of the 'higher performance' anchors being considerably superior to the likes of the Danforth and yet for a 16 ton boat they suggest 21kg, and for a 24 ton boat suggest 27kgs.

 

Many 'River Boaters' will say I cannot lift a 20 / 27kg anchor so just have a 10kg one - pretty much a waste of time and gives a false sense of security.

 

If the anchor has 'saved you and your boat' then the last thing to worry about is the recovery of the anchor - once your boat is 'sorted' you can if need be, tow the anchor out 'backwards' or even just 'abandon it' - it may have saved your life and saved a £X,XXX boat so the loss of 'a couple of hundred pounds' is insignificant.

 

Don't cut corners on safety.

Interestingly Lewmar suggest far smaller anchors for a given boat size/weight with their Delta anchors then the Ultra Anchor seem to recommend.

 

 

For our 25ft boat Delta suggest a 6kg anchor whereas the Ultra Anchor recommends closer to 10kg.

 

As it happens we are fitted with a 10kg Delta.

To be fair, I read it up on the internet, and I will be honest, it might have got thrown overboard like a broad's mud weight, had I not read up on it.

This what is in my mind at the moment...

Lower it rather than throw the anchor.

Be aware of the river flow, let out the chain/line at a similar speed to the flow rate so no chain or line fouls the anchor, when deployed, gently reverse back till it grabs. But if your engine has failed, probably need some slack in the line so the boat snatches it.

 

Now I know this is partly the jist of it, but I would welcome any advice or a link to a suitable website.

 

We need something simple, we don't want an instruction sheet to read. The action of dropping the anchor has to be instinctive bearing in mind, the stress we could be under when we have to deploy it.

Go out and practice. No point knowing the theory if you can't put it into action.