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Anchors


jonk

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Recently I needed to buy an anchor for the Teddington to Brentford section of the Thames. I went into the chandler at Teddington and explained what I wanted and he asked what type I wanted. I replied that I thought that a Danforth type would be best, but he was doubtful - he said that on the Thames they tend not to hold and a much lighter plough (CQR) anchor would be better. I was surprised but accepted his advice. His main reasoning seemed to be that no anchor is going to be able to secure a narrowboat in the tidal Thames if the current is running (about 5mph at maximum apparently) but it will pull the bow into the flow and give enough time for the emergency crew to reach the boat (they have a 15min max for reaching anyone on the Thames). He sold me a CQR of 7kg and cable without chain. This he thought would be sufficient for my 57ft narrowboat (I was thinking of a 15kg Danforth plus chain and rope), he said that the plough was much more efficient at holding a boat on the Thames and that chain was not needed but could be used if required. This was also the most cost-effective solution he claimed. Since he had recently retired from the Thames rescue service I think that he knows what he is talking about, but it does surprise me.

I am not saying this is right or wrong but I find it of interest, and the smaller anchor is easy to store in the engine hole when not deployed for river use.

 

John

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For a 60ft NB we were advised to get a 20kg Briattany type.

 

There does not seem to a definitive formula and differing advice seems to abound.

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I am a little surprised at the weight but given that the man has specific Thames professional experience then he will definitely know more than I do.

 

The internet and forums are great but sometimes they can also be a source of "received" wisdom and a collective view on "the norm" A 15Kg or so Danforth is "the norm" for narrowboats and I suspect some folk will recommend that without knowing why.

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The internet and forums are great but sometimes they can also be a source of "received" wisdom and a collective view on "the norm" A 15Kg or so Danforth is "the norm" for narrowboats and I suspect some folk will recommend that without knowing why.

 

It is the norm because of some rather silly logic that says "if you are going to struggle to lift it, it isn't any use, so buy whatever size you can pick up easily"

 

On that basis, you might as well throw a bent dessert fork attached to a length of clothesline over the side, because that will probably be just as effective as a 15kg Danforth on a 60' boat.

 

A 15kg just isn't going to hold. A 25kg, or better a 30kg is what is needed.

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I wonder if anyone has actually done any tests on different types of anchor on the Thames using a Narrowboat. There is loads of info on yachts anchoring at sea because they do it all the time, but narrowboats on the Thames?

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I'm most surprised that he recommended you didn't need chain! 10 metres of 8 - 10mm chain will keep the anchor down making it much more likely it will dig into the river bed (whatever type of anchor you use). Without the chain the anchor is likely to bounce along the bottom because it's being pulled up.

 

That's the received wisdom I have received anyway.

 

I wonder if anyone has actually done any tests on different types of anchor on the Thames using a Narrowboat. There is loads of info on yachts anchoring at sea because they do it all the time, but narrowboats on the Thames?

 

When I was moored at Brentford I did plan to go out with another boat and practice anchoring between Brentford & Teddington. There are plenty of places to do it safetly without obstructing other traffic. I never got around to it but I will do. Like anything else one needs to do in an emergency, I'm sure it's worth practicing and having some idea what the boat will do and highlight any problems before being forced to do it for real.

Edited by blackrose
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I wonder if anyone has actually done any tests on different types of anchor on the Thames using a Narrowboat. There is loads of info on yachts anchoring at sea because they do it all the time, but narrowboats on the Thames?

 

Let's commission Robin2.

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When I was moored at Brentford I did plan to go out with another boat and practice anchoring between Brentford & Teddington. There are plenty of places to do it safetly without obstructing other traffic. I never got around to it but I will do. Like anything else one needs to do in an emergency, I'm sure it's worth practicing and having some idea what the boat will do and highlight any problems before being forced to do it for real.

 

 

That's not a bad idea at all Mike, and that's what I used to do (not on the Thames) everytime I had another barge, to make sure that the winch worked well and the anchors were holding good enough, if there was a lack of current I would rev it up in reverse to check.

 

Is always better to use a bit of time to make sure everything you could have to use one day, is in for immediate action when needed.

 

Make a nice day of it, and enjoy the useful exercise.

 

Peter.

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I'm most surprised that he recommended you didn't need chain! 10 metres of 8 - 10mm chain will keep the anchor down making it much more likely it will dig into the river bed (whatever type of anchor you use). Without the chain the anchor is likely to bounce along the bottom because it's being pulled up.

 

That's the received wisdom I have received anyway.

 

 

 

When I was moored at Brentford I did plan to go out with another boat and practice anchoring between Brentford & Teddington. There are plenty of places to do it safetly without obstructing other traffic. I never got around to it but I will do. Like anything else one needs to do in an emergency, I'm sure it's worth practicing and having some idea what the boat will do and highlight any problems before being forced to do it for real.

 

I think it is good to try it out. I did on the Trent a little upstream of Trent lock. The Anchor in the conditions that day held fine although some slippage to begin with. The only thing I was worried about was getting it back! But it came up with no particular trouble.

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There's a huge amount of information available on anchoring. Basically, you need to ensure that the anchor bites, and this means it has to be big enough and heavy enough, and at the correct angle - virtually horizontal.

 

The correct angle can only be obtained if the pull from the cable is also close to horizontal. This can be achieved by using a length of heavy chain, or by using plenty of rope. And I mean plenty.

 

Both CQRs and Danforths are perfectly satisfactory, as long as they are big enough.

 

I'm not going to attempt to size your anchor for you, but I would observe that your "expert" was talking nonsense. When you anchor, you need to be held fast, and anybody who sells a 7kg anchor for a narrow-boat for use on the Thames is a clown.

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It could be that your adviser is spot-on but if I were buying an anchor/chain/warp I would buy one that would be adequate for future use, not just the Thames from Brentford to Teddington. As Dave Mayall suggests, it is more about convenience and what you can manage - a small anchor with chain is easier to chuck overboard than a big one with no chain.

 

The RNLI suggest:

When anchoring with an anchor and chain only, the minimum amount of anchor chain recommended is three times the depth of water. When using anchor, chain and warp, the length should be increased to a minimum of five times the depth of water.

In the past I had a guideline for anchor type/weight/warp length without chain but I cannot find this on the web - maybe ten times the depth?

 

The Thames at Richmond may be 5-6m deep. So, whatever size the boat or the anchor, it seems you need 18m of chain, 40m of warp + chain or, maybe, 60m of (non-floating) warp?

 

My experience is limited to anchoring a one tonne fishing boat inshore (Solent) where the depth, currents, winds and waves exceed those found on the upper tidal Thames. My experience suggests that a 'tripping rope' and a buoy when that fails, are important. i.e. the anchor never dragged but it often fouled.

 

Alan

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I would go for a Danforth say 20Kg (absolute min 15Kg) with 6-10 metres of 10mm chain plus rode (to keep total weight down) for around 60ft nb. Trouble is once set in mud they will be a pig to break out single handed or without mechanical assistance.

 

As second choice a Delta sets well & would probably break out more easily.

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need 18m of chain, 40m of warp + chain or, maybe, 60m of (non-floating) warp?

 

My experience is limited to anchoring a one tonne fishing boat inshore (Solent) where the depth, currents, winds and waves exceed those found on the upper tidal Thames. My experience suggests that a 'tripping rope' and a buoy when that fails, are important. i.e. the anchor never dragged but it often fouled.

 

Alan

Please don't take this the wrong way but this was my very point, all the calcs, charts and tables are for what you do here, because every year 100 of boaters do it, very few narrowboats get anchored on the tidal or even none tidal Thames and even less do comparisons.

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It could be that your adviser is spot-on but if I were buying an anchor/chain/warp I would buy one that would be adequate for future use, not just the Thames from Brentford to Teddington. As Dave Mayall suggests, it is more about convenience and what you can manage - a small anchor with chain is easier to chuck overboard than a big one with no chain.

 

The RNLI suggest:

When anchoring with an anchor and chain only, the minimum amount of anchor chain recommended is three times the depth of water. When using anchor, chain and warp, the length should be increased to a minimum of five times the depth of water.

In the past I had a guideline for anchor type/weight/warp length without chain but I cannot find this on the web - maybe ten times the depth?

 

The Thames at Richmond may be 5-6m deep. So, whatever size the boat or the anchor, it seems you need 18m of chain, 40m of warp + chain or, maybe, 60m of (non-floating) warp?

 

My experience is limited to anchoring a one tonne fishing boat inshore (Solent) where the depth, currents, winds and waves exceed those found on the upper tidal Thames. My experience suggests that a 'tripping rope' and a buoy when that fails, are important. i.e. the anchor never dragged but it often fouled.

 

Alan

 

18 metres of chain would be VERY heavy. Better to have at least 5 metres, plus lots of rope. Say 60 metres for the Thames down to Limehouse.

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Interesting selection of replies!

As I said - I was very surprised at the recommendation also. I suspect that the thinking goes like this:

If a boat gets into trouble on the Thames it will be rescued very quickly - assuming a cell phone is on board and the rescue number is to hand - so an anchor only needs to keep the boat safe not necessarily stationary. The plough anchor does not need as much chain and rope because of it's design - the pointed bit digs in and pulls the flukes under. A chain would assist for other reasons - absorbing shock etc. but would add to the difficulty of deploying it. The CQR sold to me is easy to deploy although it feels much heavier than the (I think) 7kg on the shaft (feels more like my 15kg Danforth at home, perhaps I am misreading the pretty illegible marks!).

While the discussion was going on another person in the shop was asked his opinion since he was active in the rescue service, he was not sure that ANY anchor light enough to use manually would be of much use on the Thames below Brentford but above the CQR was a better bet than a Danforth and would hold much better and more reliably in those conditions.

 

I don't say that they are right but it would be interesting to hear the results of any actual tests performed - as suggested in the above posts.

 

John

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I think us narrow boaters get a bit over excited about anchors etc.

 

Keep it in context. We have an anchor for emergency purposes when, on the odd occasion, we venture out on to tidal areas or fast flowing rivers.

 

The salty people use an anchor all of the time as a matter of routine. They need an anchor to hold so that they can sleep at night/temporarily leave the boat etc.

 

Jonk. I don't think your man was far off wrong. I would add a bit of chain to it. All the anchor needs to do is hold the boat head to stream and if it drags a bit, so what. In the event of trouble, you contact London VT'S on the radio and help will be with you.

 

If people ask me what anchor to use on fast flowing rivers, I always say none. Invest in a decent grappling hook and a long length of rope (also practise throwing it). You're never to far away from something that you can snag.

 

If you want to make a real investment. Spend your money and time in making sure that the engine is well serviced/reliable and the boat (and crew) is well prepared.

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If your engine fails as you are approaching a bridge, there is very little chance that you will be rescued in time, so an anchor that can hold you is, in my view, essential.

 

When I needed to anchor in a hurry, with the tide ebbing strongly, I was very glad that my massive Fisherman anchor held me fast, and I was able to fix the throttle problem. Although far from an optimal design, the Fisherman works because it is very heavy.

 

Depending on where you are, it might take up to 20 minutes for an RNLI boat to reach you, though generally it will be more like 5 to 10. And that's if they are not rescuing somebody else at the time.

 

The Danforth and CQR anchors were designed over 70 years ago, and are out-performed by modern designs such as the Rocna. However, the Danforth is especially good in mud and sand (better than the CQR), and is therefore well-suited to the Thames, contrary to what the chap in the shop was saying. It's also easy to stow.

 

I doubt if people involved in rescues on the Thames know more about anchoring than anybody else. Why should they? Generally, they are rescuing people who have fallen out of rowing boats.

 

Much information on anchoring comes from America. It's worth remembering that many American sailors visit the Caribbean, where they meet coral, and where sandy bottoms are often covered in weed. Because of the coral, they prefer to use chain rather than rope, and because of the weed, some don't like Danforths. However, when I lived in the Caribbean I used a Danforth on a 32 ft sailing boat and never had a problem.

 

Although the catenary formed by a chain will absorb shock, so will a rope, which should be made of nylon for that reason.

 

Another point about chain is that it is not really practicable to use it without a windlass. Hence my suggestion of a short length of chain, attached to lots of rope.

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I think us narrow boaters get a bit over excited about anchors etc.

 

Keep it in context. We have an anchor for emergency purposes when, on the odd occasion, we venture out on to tidal areas or fast flowing rivers.

 

The salty people use an anchor all of the time as a matter of routine. They need an anchor to hold so that they can sleep at night/temporarily leave the boat etc.

 

Jonk. I don't think your man was far off wrong. I would add a bit of chain to it. All the anchor needs to do is hold the boat head to stream and if it drags a bit, so what. In the event of trouble, you contact London VT'S on the radio and help will be with you.

 

If people ask me what anchor to use on fast flowing rivers, I always say none. Invest in a decent grappling hook and a long length of rope (also practise throwing it). You're never to far away from something that you can snag.

 

If you want to make a real investment. Spend your money and time in making sure that the engine is well serviced/reliable and the boat (and crew) is well prepared.

 

Thanks, food for thought!

 

John

 

If your engine fails as you are approaching a bridge, there is very little chance that you will be rescued in time, so an anchor that can hold you is, in my view, essential.

 

When I needed to anchor in a hurry, with the tide ebbing strongly, I was very glad that my massive Fisherman anchor held me fast, and I was able to fix the throttle problem. Although far from an optimal design, the Fisherman works because it is very heavy.

 

Depending on where you are, it might take up to 20 minutes for an RNLI boat to reach you, though generally it will be more like 5 to 10. And that's if they are not rescuing somebody else at the time.

 

The Danforth and CQR anchors were designed over 70 years ago, and are out-performed by modern designs such as the Rocna. However, the Danforth is especially good in mud and sand (better than the CQR), and is therefore well-suited to the Thames, contrary to what the chap in the shop was saying. It's also easy to stow.

 

I doubt if people involved in rescues on the Thames know more about anchoring than anybody else. Why should they? Generally, they are rescuing people who have fallen out of rowing boats.

 

Much information on anchoring comes from America. It's worth remembering that many American sailors visit the Caribbean, where they meet coral, and where sandy bottoms are often covered in weed. Because of the coral, they prefer to use chain rather than rope, and because of the weed, some don't like Danforths. However, when I lived in the Caribbean I used a Danforth on a 32 ft sailing boat and never had a problem.

 

Although the catenary formed by a chain will absorb shock, so will a rope, which should be made of nylon for that reason.

 

Another point about chain is that it is not really practicable to use it without a windlass. Hence my suggestion of a short length of chain, attached to lots of rope.

 

Thanks,

That is interesting. I am not sure about the bridge though - if the boat is being held into the stream surely it will be pulled through the bridge-hole on the stream?

I use a Danforth here on sand and it works well but I can see that a CQR could be better in some circumstances. The problem with any anchor is the weight required to be effective and chain just makes things worse! I use a 15kg Danforth with about 4m of chain and about 8m of rope for depths of about 2 - 4m of sea/lagoon, this seems to work well.

 

John

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Thanks, food for thought!

 

John

Except that a 7kg CQR, trying to set in Thames mud, dangling off a 60' narrowboat won't drag, it will pop out.

 

Also, if you are in the middle of a fast flowing river, you don't want to be looking for something to aim your throw at.

 

Chuck a decent anchor into the water and it will have a river bed full of mud, to aim for.

 

I'd rather have that target than a branch, that I've got to hit with a hook, whilst heading for disaster, hoping that it won't be a dry dead twig, if my aim does happen to be true.

 

20kg Danforth, 15m of chain, 30m of rope. Fastened to the front, fed back to the steerer, going upstream. Fastened to the back, going downstream.

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Except that a 7kg CQR, trying to set in Thames mud, dangling off a 60' narrowboat won't drag, it will pop out.

 

Also, if you are in the middle of a fast flowing river, you don't want to be looking for something to aim your throw at.

 

Chuck a decent anchor into the water and it will have a river bed full of mud, to aim for.

 

I'd rather have that target than a branch, that I've got to hit with a hook, whilst heading for disaster, hoping that it won't be a dry dead twig, if my aim does happen to be true.

 

20kg Danforth, 15m of chain, 30m of rope. Fastened to the front, fed back to the steerer, going upstream. Fastened to the back, going downstream.

 

:lol: You are probably right! :cheers:

 

John

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Fastened to the front, fed back to the steerer, going upstream.

 

Hi Carl,

Do you mean the rope is tied off at the bow but the chain and anchor are then stowed at the rear so the steerer can deploy it over the side without rushing to the bows ?

Cheers

Les

PS Just back from Thames trip with 'borrowed' anchor/chain/rope which I think may have been inadequate !! It was all stowed up in the bows too.

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