Anchor for the Thames

[Cal Ando]

5 minutes ago, Alan de Enfield said:

 

When anchoring you should be using 100% chain anyway - much less space taken up as you ony need 3 to 5 times depth instead of 10x depth with rope.

Never heard this.   I was always told that the anchor holds the chain, the chain anchors the boat and the warp attaches the boat to the chain.  I've got 10m chain spliced to 30m rope - enough to hang oneself as they say!

[Alan de Enfield]

1 minute ago, Cal Ando said:

Never heard this.   I was always told that the anchor holds the chain, the chain anchors the boat and the warp attaches the boat to the chain.  I've got 10m chain spliced to 30m rope - enough to hang oneself as they say!

Probably not told you by people who anchor every day / night and don't want their boat dragging its anchor.

[Chewbacka]

9 minutes ago, ditchcrawler said:

I wouldn't be out on a river running at 7Kts in a Narrowboat, but I'm a wimp.

I agree, no point going up river if the flow is faster than 3mph as my narrowboat boat won’t go over about 4 to 5 mph so will take forever to get any distance.  Probably n out of diesel before I get where I am going.  Likewise going down stream and unable to stop even with full reverse is not going to end well. 

[Jen-in-Wellies]

8 minutes ago, Cal Ando said:

As usual, Jen, you've provided a great solution.   Many thanks. 

I'll chuck a chain and shackle round the scuppers and attach the warp to that.   Now whats the breaking strain of the shackle?.....

Good idea using chain instead of rope for this attachment. Gets round the risk of the sharpish edge of the scupper going through the rope. wrapping something round the chain would prevent damage to paintwork. Perhaps a canvas tube sewn round it? 

Jen

[David Mack]

22 hours ago, Cal Ando said:

 

I'm planning to sit my anchor and warp etc on a purpose made cradle on the roof at the front, when cruising the upper Thames, with the  warp routed neatly down the front of the cabin to an eye ring on the well deck that's an emergency, last stop back-up anchor point. 

 

So with the anchor on the roof at the front, and you at the stern how do you propose to deploy the anchor in this hypothetical emergency situation?

 

And once you have boated the Upper Thames to Lechlade, turned round and you are on your way back downstream, what happens when you deploy your anchor with the warp secured in the well deck? The boat continues downstream, passing over the anchor, at some point the warp goes tight, the bow stops moving, the stern carries on, the boat spins round and you end up wedged across the channel.

[Alan de Enfield]

17 hours ago, Cal Ando said:

Never heard this.   I was always told that the anchor holds the chain, the chain anchors the boat and the warp attaches the boat to the chain.  I've got 10m chain spliced to 30m rope - enough to hang oneself as they say!

 

 

There will shortly be a comment that 'anchoring at sea' is very different to anchoring on a River - and - yes I agree, it is.

 

Anchoring at sea is a normal practice undertaken most nights, it is planned and considered and a suitable spot chosen, the anchor is carefully, and correctly deployed, and the boat reversed to help the anchor set, if the anchor 'drags' you simply pull it back in, motor back to your chosen spot and repeat the process until the anchor sets properly.

 

Deploying an anchor on a river will generally be during a 'brown trouser' moment, the engine has stopped, gearbox not working (or whatever). You now need an emergency brake (to stop you going over a weir ?) and the anchor needs to work and set properly and be able to hold the boat to an emergency stop instantly, FIRST TIME, EVERYTIME, as there is unlikely to be time to pull it back in and re-set again.

 

So, yes anchoring on a River is different and actually is much more demanding than anchoring at sea.

 

There are any number of articles about anchoring 'sea-boats' but (seemingly) non about emergency anchoring of River boats, so we can only try and extrapolate the knowledge of 250,000+  'coastal boaters' to the 80,000 inland waterways boaters.

 

An extract from an article I found (so as not to influence the discussions with my own experiences)

It is interesting to note that using the same length of rope as you would chain gives you a much reduced 'holding power', so, a scope of 4/1 rope will only provide about 55% of the anchor holding power' as using a 4/1 scope of chain.

 

"Scope" is the ratio of depth to length, (so, for example, a scope of 10/1 means that for every metre of water depth you need 10 metres of Chain / Rope)

 

What Length of Mooring Chain Should I Use?

During the last seven and half months, I spent 129 days anchored (out of 228) in 61 different anchorages. The mean water depth was 6.50 meters and the scope 5/1. The total length of the anchor chain was about 30 meters, of which 23.5 meters was lying on the bottom (30 - 6.50 m) Therefore, I believe a length of about 25 meters is perfect. If the water height is less, then you will be anchoring with an all mooring chain line... if the wind build up, you can pay out more scope but the wind will push the boat and the mooring chain will not chafe on the bottom.

What Length of Anchoring Rope Should I Use?

Holding is in direct relation to the pulling length of the rope... (Or more accurately, the pulling angle). Generally speaking, with a scope of 4/1 you will have about 55 % of the maximum holding of the anchor, with a scope of 6/1 about 70 % with a scope of 8/1: 80 % and with 10/1 about 85 % the maximum. - 100% holding will be achieved with a horizontal rope or an "Infinite/1 scope.

Increasing the scope will be efficient up to 10/1 - With more than 10/1; a large increase in the scope will give only a negligible increase in holding. Therefore, the total length of the rope has to be adapted in relation with the conditions you are expecting to meet, and should be about ten times the maximum depth you expect have to anchor in. (I suggest 100 meters).

 

 

 

 

Edited August 5, 2020 by Alan de Enfield

[David Mack]

14 minutes ago, Alan de Enfield said:

 

Deploying an anchor on a river will generally be during a 'brown trouser' moment, the engine has stopped, gearbox not working (or whatever). You now need an emergency brake (to stop you going over a weir ?) and the anchor needs to work and set properly and be able to hold the boat to an emergency stop instantly, FIRST TIME, EVERYTIME, as there is unlikely to be time to pull it back in and re-set again.

 

Exactly this. But the riverboater will have zero experience of ever having done this, so the chances of a successful deployment, even with the best equipment, are low.

Yet we hardly ever see reports of brown-trousered boaters being washed over weirs.

Most narrowboat anchors will never get used in anger, most are inadequate should they be needed, and most boaters are too inexperienced to use them anyway. 

Which does raise the question, Why bother to have one at all?

[IanD]

2 minutes ago, David Mack said:

 

Exactly this. But the riverboater will have zero experience of ever having done this, so the chances of a successful deployment, even with the best equipment, are low.

Yet we hardly ever see reports of brown-trousered boaters being washed over weirs.

Most narrowboat anchors will never get used in anger, most are inadequate should they be needed, and most boaters are too inexperienced to use them anyway. 

Which does raise the question, Why bother to have one at all?

Paperwork and box-ticking? Or maybe there has actually been a rare occasion when one was needed and it did the job and saved a narrowboat -- does anybody know of one?

[Alan de Enfield]

6 minutes ago, David Mack said:

Which does raise the question, Why bother to have one at all?

Probably because the PLA insist on them, and the Insurers may be a bit 'wiffy' if you don't have one.

 

I personally know of only 2 examples on the River Trent, both with NB's.

One which deployed and (eventually) held about 50 yards short of going over Cromwell weir, and the other many years ago, further upstream when the anchor  didn't set and they went over the weir.

Just now, IanD said:

Paperwork and box-ticking? Or maybe there has actually been a rare occasion when one was needed and it did the job and saved a narrowboat -- does anybody know of one?

 

Yes.

 

He was a member on this forum, I was there & we towed him back into Kings Marina after engine failure.

Edited August 5, 2020 by Alan de Enfield

[Alan de Enfield]

On 16/07/2020 at 11:07, Yeletah said:

20kg Brittany anchor, 10m of 8mm chain and 20m warp

or

16kg Brittany anchor, 9m 10mm chain and 20m warp

The Brittany is a 'medium performance anchor' and not commonly used now that '3rd generation' better performing anchors are available.

 

 

 

 

 

[Cal Ando]

  17 hours ago, ditchcrawler said:

I wouldn't be out on a river running at 7Kts in a Narrowboat, but I'm a wimp.

 

17 hours ago, Chewbacka said:

I agree, no point going up river if the flow is faster than 3mph as my narrowboat boat won’t go over about 4 to 5 mph so will take forever to get any distance.  Probably n out of diesel before I get where I am going.  Likewise going down stream and unable to stop even with full reverse is not going to end well. 

I agree with both Ditchcrawler and Chewbacka, and wouldn't choose to go in a 7 knt stream for fun.   However I have done it.   Boards were shunting between red and yellow on the Thames and we needed to move the boat.  Prior to casting off I ensured: my Beta 43  had enough guts to stop astern when going downstream, it had enough oomph to push it upstream, the engine was reliable and had sufficient fuel, the anchor was available, and I knew how the boat would handle if I tried anything clever.  Then ensured I didn't try anything clever!    This was when we were moving the boat from Pyrford to the K&A having just bought her and needed to be done in a few days, so wasn't going to take any chances with a new pride and joy that I hadn't got to know properly.    The trip upstream was 'eventful' and a great learning experience but we ensured we never placed ourselves  or more importantly, could place ourselves, in a situation we couldn't handle.   BTW she stopped (i.e. no forward motion) under the Albert Bridge at Windsor running at 70% power and needed 90% to clear the bridge.   That was somewhat nerveracking.

[Cal Ando]

1 hour ago, David Mack said:

 

So with the anchor on the roof at the front, and you at the stern how do you propose to deploy the anchor in this hypothetical emergency situation?

 

And once you have boated the Upper Thames to Lechlade, turned round and you are on your way back downstream, what happens when you deploy your anchor with the warp secured in the well deck? The boat continues downstream, passing over the anchor, at some point the warp goes tight, the bow stops moving, the stern carries on, the boat spins round and you end up wedged across the channel.

Thought about both these and welcome further debate.   

My opinion is, in normal running I don't want the anchor at the back and I don't want to deploy if from the stern, thus I have it at the front.   True, my wife probably couldn't lift it but could tip it off the cabin roof.   Hopefully not getting entangled in anything  I'm also aware you should 'deploy' it rather than chuck it overboard as the chain will form a useless lump on the bottom.   

Thus I need to deploy it and I'll be at the back. BUT...

1  Unless you're tettering on the edge of a weir - and you shouldn't have got into that situation - you don't need to deploy the anchor NOW!   A few seconds extra shouldn't make any difference.  Worst case scenario is waiting for a  lock near the weir and the engine dies .  You've got time to calmly get to the front, deploy it properly, let it bite and tie it off before you get into a real rescue situation.  Urgent, yes, panic no.

2. If the engine stops for any reason and immediate restarts fail, then you have no thrust and you will soon be moving at the same speed as the stream, so no steerage wey either.   If you neither, steer, nor control the speed, there's not much point in being at the back! - so you might as well go to the front and deploy the anchor.   Its also got the advantage that the toilet is between you and the anchor which may be useful initially!

 

[Keeping Up]

Generally I keep the anchor at the bows and, when going downstream, a mud weight at the stern. It wouldn't stop the boat in a strong stream (although it does in a gentle flow) but it would slow it considerably and keep the boat facing the right way (essential in a narrow channel) while I take my time deciding on the best course of action from a choice of deploying the anchor from the bow, or carrying it through to deploy from the stern, or just drifting while I fix the problem.

[OldGoat]

6 minutes ago, Cal Ando said:

Thought about both these and welcome further debate.   

My opinion is, in normal running I don't want the anchor at the back and I don't want to deploy if from the stern, thus I have it at the front.   True, my wife probably couldn't lift it but could tip it off the cabin roof.   Hopefully not getting entangled in anything  I'm also aware you should 'deploy' it rather than chuck it overboard as the chain will form a useless lump on the bottom.   

Thus I need to deploy it and I'll be at the back. BUT...

1  Unless you're tettering on the edge of a weir - and you shouldn't have got into that situation - you don't need to deploy the anchor NOW!   A few seconds extra shouldn't make any difference.  Worst case scenario is waiting for a  lock near the weir and the engine dies .  You've got time to calmly get to the front, deploy it properly, let it bite and tie it off before you get into a real rescue situation.  Urgent, yes, panic no.

2. If the engine stops for any reason and immediate restarts fail, then you have no thrust and you will soon be moving at the same speed as the stream, so no steerage wey either.   If you neither, steer, nor control the speed, there's not much point in being at the back! - so you might as well go to the front and deploy the anchor.   Its also got the advantage that the toilet is between you and the anchor which may be useful initially!

 

That's perhaps the most sensible coment thus far.

 

IME - you shouldn't be on the tidal thames without an anchor

On the non tidal bit regulations say you should / must have an anchor and KeepingUp's suggestion is a reasonable compromise

If the River is running at more than 1 knot - then you shouldn't be out anyway, and the River will be on Red Boards

If you can't lift an anchor - then get a lighter one. You need something that can dig in - which is difficult anyway as much of the bottom is gravel.

We have a 25kilo Danforth, chain and line. The only time we've use it is when we stopped for lunch in the  weir pool  at Cookham. It wasn't very effective - because it couldn't grip, it dragged.

 

[Iain_S]

19 hours ago, Cal Ando said:

Like the blind fawn - no eyed-deer.   Almost certainly the water tank but unless its a weird bespoke shape, probably not where I want to put the ring.  (right by the gunnel and right in front of the cabin bulkhead.

BUT I now know the force of my boat being stopped is:  1/2mV*V/d    (1/2 M Vsquared / distance over which force acts)

where m is the mass of the boat, V is its speed and d is the distance taken to stop from its travelling speed to 0 (i,e, snatch distance)

m = 17,000 kg, V = 7 knots = 3.6m/s (YIKES) and d = 4m allowing for anchor movement when biting, rope stretch etc

THUS force = 27,540 Newtons which = 2,808 kg or about 3 tonnes

 

Thus in theory, any chinese steel M12 bolt from Lidl which would be rated at 4 tonnes should be adequate.

 

If my estimate of 4m  stopping distance is inaccurate and it's 2 m, then this is double the force so would need M16 to be safe

A good argument for lowering an anchor rather than dropping it! Other problem with just chucking everything over board is that the chain could end up on top of and around the anchor, and a fluke with a loop of chan round t is never going to bite.

18 hours ago, Cal Ando said:

As usual, Jen, you've provided a great solution.   Many thanks. 

I'll chuck a chain and shackle round the scuppers and attach the warp to that.   Now whats the breaking strain of the shackle?.....

Use rated shackles. The rating is usually around half the actual breaking strain.

[Alan de Enfield]

5 minutes ago, OldGoat said:

We have a 25kilo Danforth, chain and line. The only time we've use it is when we stopped for lunch in the  weir pool  at Cookham. It wasn't very effective - because it couldn't grip, it dragged.

Unfortunately that is the problem with the Danforth. Narrowboaters buy them only taking into consideration that they fold flat to fit into a locker and 'look tidy', when the deciding criteria should be functionality and performance.

 

The Brittany is of much the same design.

 

Performance of the Danforth 29/70

 

 

Edited August 5, 2020 by Alan de Enfield

[ditchcrawler]

5 hours ago, Cal Ando said:

  17 hours ago, ditchcrawler said:

I wouldn't be out on a river running at 7Kts in a Narrowboat, but I'm a wimp.

 

I agree with both Ditchcrawler and Chewbacka, and wouldn't choose to go in a 7 knt stream for fun.   However I have done it.   Boards were shunting between red and yellow on the Thames and we needed to move the boat.  Prior to casting off I ensured: my Beta 43  had enough guts to stop astern when going downstream, it had enough oomph to push it upstream, the engine was reliable and had sufficient fuel, the anchor was available, and I knew how the boat would handle if I tried anything clever.  Then ensured I didn't try anything clever!    This was when we were moving the boat from Pyrford to the K&A having just bought her and needed to be done in a few days, so wasn't going to take any chances with a new pride and joy that I hadn't got to know properly.    The trip upstream was 'eventful' and a great learning experience but we ensured we never placed ourselves  or more importantly, could place ourselves, in a situation we couldn't handle.   BTW she stopped (i.e. no forward motion) under the Albert Bridge at Windsor running at 70% power and needed 90% to clear the bridge.   That was somewhat nerveracking.

Sounds to me you took all the chances in the world, would you have died or lost the boat had you decided not to do that journey, on a boat you didn't know. I couldn't stop in a 7kt flow or turned round and gone back. If the boards are going on why not just stop and wait, even if its for a month.

[blackrose]

On 16/07/2020 at 11:57, Stilllearning said:

At least 20kg, imho, and as much chain as you can, ideally the length of the boat? Then twice as much rope, and think about how to deploy the anchor in an emergency. If the anchor is at the bow, and you are alone at the stern, it won’t be much use...

 

It will be of more use than not having an anchor. If you're in a situation where need to deploy an anchor then your usefulness at the helm is likely to be fairly limited, so even as a single handed boater it would probably be wise to get one's arse to the bow and deploy! 

 

I've been single handed on a widebeam on rivers for the last 10 years and don't have a problem leaving the helm in certain conditions. I certainly wouldn't be without my anchor.

[Cal Ando]

5 hours ago, Alan de Enfield said:

 the Danforth. Narrowboaters buy them only taking into consideration that they fold flat to fit into a locker and 'look tidy', when the deciding criteria should be functionality and performance.

 

 

Are we talking about the same thing?   Mine doesn't fold flat, won't fit ANYWHERE conveniently and when we were running on yellow boards we first had it in the welldeck where it was a positive death trap to anyone working the bow lines.  Hence its hasty elevation to the roof.   

I spent a lot of time and research before buying my anchor.   I'd love a Spade anchor, but price is also a consideration and £1200 is not in our budget.  The Danforth seemed to be the best compromise regarding functionality, performance and price.

[Alan de Enfield]

23 minutes ago, Cal Ando said:

Are we talking about the same thing?   Mine doesn't fold flat, won't fit ANYWHERE conveniently and when we were running on yellow boards we first had it in the welldeck where it was a positive death trap to anyone working the bow lines.  Hence its hasty elevation to the roof.   

I spent a lot of time and research before buying my anchor.   I'd love a Spade anchor, but price is also a consideration and £1200 is not in our budget.  The Danforth seemed to be the best compromise regarding functionality, performance and price.

A Danforth folds flat such that the stock fits in between the flukes. It is 'wide' but flat so can fit into NB lockers in the well deck (for example)

 

 

 

 

 

Without disassembly my 30kg Mantus anchor would take a huge amount of storage space if it was not kept on the bow-roller.

The stock is almost 1 metre long so you can see how big a 'beast' it is.

 

 

 

Edited August 5, 2020 by Alan de Enfield

[Tim Lewis]

On 16/07/2020 at 11:07, Yeletah said:

I'll soon be taking a trip up the Thames from Brentford to Oxford on a 70' narrowboat. The boat currently has no anchor so I need to establish exactly what I need in terms of anchor weight, size and length of chain and warp length.

 

I've been in touch with an anchor supplier to ask this question after providing the same info and they suggested the following options:

 

20kg Brittany anchor, 10m of 8mm chain and 20m warp

or

16kg Brittany anchor, 9m 10mm chain and 20m warp

 

Both options weigh a total of around 35kg although I'm erring towards option 2 as a 16kg anchor might be easier to pick up and manoeuvre overboard than the 20kg version.

 

The supplier did suggest I got a second opinion hence this post but all thoughts welcome!

 

From the IWA Thanes Tideway guide:

 

 

[Cal Ando]

Thanks Tim for this.   The text suggests that my 10m of chain and 30m of rope is still too short for Limehouse. (45m chain or 75m rope).   Anyone else carry this much and still float?   Better stick to Brentford then!

I notice from the phone number that the text is really old.   Whilst information such as this is still relevant, hopefully the Thames might have silted up a few metres by now!

 

[Cal Ando]

11 hours ago, OldGoat said:

The only time we've use it is when we stopped for lunch in the  weir pool  at Cookham. 

 

I assume this was below the weir.   There's a really cute spot right at the top that we got into with our 23' Freeman (snuck down there backwards for safety the first time as it was within a few feet of the weir. and right beside the lock bridge)   I was hoping you'd found a way to get in there with a narrowboat!  Again, backwards with a dangling Danforth (oh -er Missus) would seem interesting!

[Cal Ando]

Modern Pop anchors:

Alan's mentioned Brittany and Spade anchors.   But some are notorious for needing several attempts to grip the river bed.

The worst of these are the Britney Spears anchor - "Baby, Baby one more time" and "Work Bitch!"

and the Beyonce anchor - "uh oh! uh oh!" 

[Cal Ando]

6 hours ago, Alan de Enfield said:

 

 

Alan, I've tried but can't resist it.  PLEASE take this comment as humorous rather than critical.

"and as the roar of 1/4 million gallons of water hurling over the weir grows even louder she raises her voice to be heard...

'step 14!  Attach left end of roll bar 'D; to port side Fluke 'F' using M10 x 25 bolt 'K''