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11:32 pm
Wednesday,28 March, 2012
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Hi everybody,
I am planning to take my 70ft narrowboat onto moving waters, – not just rivers but the tidal section of the River Thames. I shall need two anchors – one at each end. Which is used depends of course on whether I am going downstream or upstream. (I may be working singlehanded so will not have time to fiddle about, – they need to be secured ready for instant deployment! ) Can anyone advise me as to what size Danforth I shall need to hold back 20 tons of boat that could be moving over the ground at 10 mph. Any comments and help will be much appreciated.
Thanks. Norman.
5:51 am
Friday,19 February, 2010
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Hi Norman, Here’s a post which may help you.
I haven’t heard of a narrowboat with two anchors on board before. You normally have the anchor stowed on the front deck so that the bow is into the current when you are moored. What style stern do you have? If it’s trad, you’re going to have an issue storing your anchor at the rear of the boat.
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11:25 am
Thursday,12 January, 2012
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I have a single 20 Kg Danforth with 6 metres of 10mm chain spliced to 20 metres of anchorbraid for my 60 ft nb.
I doubt you would be able to recover anything heavier without an anchor winch.
Regards – Richard –
Ecky Thump
6:41 am
Tuesday,18 September, 2012
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Hi Richard,
You say you spliced the chain onto the anchorbraid. Could you expand a bit on this?
Alan
Retired; Somerset/Dorset border when not out and about on Lucy Lowther
Days without name and hours without number
http://thelovelylisanarrowboat.blogspot.co.uk
8:27 pm
Thursday,12 January, 2012
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Alan said
Hi Richard,You say you spliced the chain onto the anchorbraid. Could you expand a bit on this?
Alan
Check out here, specifically 8 strand to chain.
Regards – Richard –
Ecky Thump
10:49 pm
Wednesday,28 March, 2012
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Hello again and thank you all for your comments.
Paul, I know that normally one would head upstream and use a bow anchor but that assumes you are planning to anchor. I dont expect I shall be planning to anchor as such – normally I would want to be mooring alongside something. The anchors are for when something goes drastically wrong,- like engine failure. If that happens I’ll need to be able to control the boat quickly – whichever way I happen to be facing in the current and most likely going downstream!
It is a trad stern, by the way, and yes I know I shall have a problem with storage;- which is why, apart from cost, I don’t want any larger than necessary.
UK Yacht Rigging and Supplies sell Danforth kits (on E-bay) – the largest seems to be 10 kgs . They do various combinations of chain and nylon rope. I was thinking about 10m of 8mm chain and 30m of 14mm nylon. The question is, how much boat will that size Danforth hold?
A narrowboat is proportionately smaller in cross section than most of the vessels that would usually be using an anchor and so I would expect that the resistance to current flow was less (weight for weight). Therefore a smaller anchor would be needed to prevent a narrowboat dragging it than for a similar displacement of seagoing boat? Does this make sense?
I note that you have a 20kg on your boat, Richard. Was that what was recommended or did it just sort of happen that way? It sounds like a fair old lump to pull back on board, – especially if it fouls.
. Do you set a trip line, by the way?
Thanks and best regards to all,
Norman
9:22 am
Tuesday,18 September, 2012
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Hi Norman,
Like you (and most narrowboaters I presume) I only intend to use the anchor for emergencies.
I have been giving some thought to how to have it ready for deployment when on a river.
As a single-hander I think I will have to keep the anchor on the stern ready to hand as it might take too long to reach the bow in an emergency. Do I then attach to the bow or the stern? As a novice I would think the stern would be preferable when going downstream but if going upstream I guess it should be the bow. I thought if I ran the rope along the roof I would have time to flick it off and ensure it did not snag on anything before the strain comes on? But not ideal. If I put the anchor on the bow would I have time to get to it?
I intend to stow the chain in a locker when on canals, keep the anchor on the roof and probably (as a single-hander) use the rope as an additional bow line available from the stern.
Comments/suggestions please.
A 20kg anchor was recommended to me for 54ft – and that might not be enough if the riverbed is rocky. Big difference between what is necessary to stop a narrowboat and a cruiser.
Alan
Retired; Somerset/Dorset border when not out and about on Lucy Lowther
Days without name and hours without number
http://thelovelylisanarrowboat.blogspot.co.uk
10:58 am
Thursday,12 January, 2012
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I think your 20 Kg anchor will be fine and tbh you would be hard put to manually recover anything heavier single-handed.
Deployment will ideally be from the bow since a boat is designed to take flow from that direction. It makes no difference which way the current is flowing. The bow will lie to the greater force, current or wind, usually the former.
I guess a very narrow river may have a bearing on that decision though, but remember eventually in a tidal river the current is going to change.
Regards – Richard –
Ecky Thump
11:12 am
Wednesday,5 December, 2012
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We have a ‘Fortress’ anchor. It is manufactured in the US and is similar to a Danforth but about half the weight for an equivalent size.
They are not cheap but are much easier to handle and stow.
The anchor should be ready for a speedy deployment in an emergency. It would ideally be able to be deployed from the stern if you were single handed with the line running forward to the bow. The low freeboard of a narrowboat would probably make it inadvisable to anchor stern first in a strong flow. Anchors intended to be used on tidal or even moderately flowing rivers would need several metres of chain attached to the anchor itself and then anchor line from the chain to the boat (overall length dependent on multiples of maximum depth of water). In lieu of chain it would be possible to use a weighted line (there are some purpose made anchor lines which are weighted for part of their length with something like lead shot). The chain is to assist the anchor to bed in properly. Just using line alone runs the risk of the anchor pulling out or not setting properly. Just what you don’t need in an emergency! My thought is to have the anchor accessible near the stern and run the anchor line forward to the bow where the excess line is coiled up in a large bucket to assist free flow, the end being secured to the boat. The line running forward down the side of the boat could be attached to the hand rail at several points using a breakable binding (rubber bands or similar!). They need to be strong enough to hold the line in place but would break instantly if the anchor was deployed. It may sound a little ‘heath robinson’- ish but I used a similar system when I was single handing a cruising yacht, when motoring in and out of harbours, just in case of engine failure or more likely, fouled prop. I had to use it once in anger and it worked a treat!.
This is not intended as a permanent fixture, but can be quickly arranged just before a river or tidal passage.
Ken
3:27 pm
Tuesday,18 September, 2012
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Thanks for the replies, Richard & Ken.
My thought of deploying from the stern when going downstream was that if, say, the engine fails heading towards a bridge or weir the boat would swing round so another 54ft stopping distance – in addition to the 30mtr rope and 10m chain. And could hit something when swinging round. But, I appreciate the norm would be the bows into the current.
Not intending to do any tidal cruising until I am a lot more experienced. The boat is currently in Nottingham so on my first outing I will be very soon on the Trent!!
Retired; Somerset/Dorset border when not out and about on Lucy Lowther
Days without name and hours without number
http://thelovelylisanarrowboat.blogspot.co.uk
9:35 pm
Wednesday,28 March, 2012
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Hi Everyone and thankyou for your comments.
Alan, you seem to be in a similar position and thinking the same way as I do. Single handed is a whole new challenge isn’t it.
Richard, and Ken; no disrespect, but I would be seriously worried if I were heading downstream out of control and the anchor was up front. If the bow end stops first, the back end will try to overtake it somehow. That means my 70ft boat is going crossways on to the current with all sorts of possible outcomes, – most of which don’t bear thinking about. No. When heading downstream the anchor must be tied to the stern to stop the boat straight in line with the current flow. That puts least strain on the anchor and doesn’t risk the boat rolling over. I do take the point about the stern being more susceptible to broaching but in the circumstances it would probably be less of a risk than having the boat across the flow.
When heading upstream then fine, deploy the anchor from the bow. If you deploy from the stern but the rope is tied on at the bow then the boat will travel back downstream for an extra twice its length before the strain comes on the anchor!
So do I gather then that most people think that a 20kg Danforth should be ok for a 70 footer? In which case and with the benefits of your comments, I shall probably invest in just the one anchor, but tie it on and position it according to which way I’m travelling in relation to the current.
Thanks again for your comments and suggestions. Best regards to you all.
Norman. NB Teal.
6:18 am
Tuesday,18 September, 2012
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Hi Norman
My thoughts exactly on the anchor – hopefully we will never have to put it into practice!
Have you seen Colin Edmondson’s “Going It Alone”? Some useful tips – and some I will not be trying for quite a while, if ever!
Alan
Retired; Somerset/Dorset border when not out and about on Lucy Lowther
Days without name and hours without number
http://thelovelylisanarrowboat.blogspot.co.uk
11:00 am
Wednesday,28 March, 2012
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Hi Alan,
No, I haven’t seen that yet – I’ll look it up . thanks. I too hope we’ll never need to put it into practice but I think we need to have it straight in our heads as to what we’re going to do if the situation ever arises. It’s a bit like going on a First Aid course! Like you, I shall be going single handed at times so need to be prepared. Btw, last evening I googled ‘anchoring a boat’ and read through a few of the results. I suggest you might like to do the same. I learned a lot about setting and retrieval and how much rode to use for the scope!
Best regards, Norman
9:37 pm
Wednesday,28 March, 2012
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Hi again everyone,
Here’s some food for thought –
I did some more research and found that the Thames at London bridge varies in depth between about 8 and 10 metres at high water depending on spring or neap tides. This means that IF you ever needed to anchor in that part of the river you will need up to 50 metres of chain/rope combo for the anchor not to drag. It is advised that the first 10-15m from the anchor should be chain to help prevent the anchor breaking out on load as the weight of the chain will keep the pull fairly parallel with the river bottom. The use of an anchor weight part way up the rope will also help in this respect.
Hope this may help someone. Best wishes to all,
Norman.
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