Anchor size?

[carlt]

INTERESTING. IS Carlt an administrator, am I treading on toes. His last post with regard to me has been added to with no mention of an edit ???

There is almost certainly a conspiracy afoot!

[carlt]

I'm not sure it has global significance, though.

[churchward]

But my eyesight isn't good enough to be able to say if a tee-stud weld is good or not, no matter how pretty it is with it's paint and all.

 

Richard

 

Our previous tee stud I would have trusted. It was made of 1" bar drilled through and welded inside the gas locker as well as on the top. We pulled the top bar off in Tewkesbury lock by hanging the boat on the gate chains.

Yes it does depend on your experience but it is possible to recognise a good weld by eye perhaps not flawless but I trust my own judgment. It is also perfectly possible to break a fixing bolted down in the situation you describe. That was my original point either method of fixing can fail given a fault and enough strain placed on it.

[carlt]

That was my original point either method of fixing can fail given a fault and enough strain placed on it.

I'm confident about my anchor fixings:

[churchward]

I would think the T-Stud welder's intention was to give you a nice sturdy mooring fixture. "What do you mean you used it to stop 20 tonnes dead?! Of course it sheered off! What did you expect? It is for mooring!"

It may sheer off but so may a bolt fixing they won't take unlimited strain either. However, one of the advantages of using a rope is that the stretch of the rope will help to stop the strain snatching the fixing hard and of course it not likely that the anchor will grab hold of the bed immediately.

 

There are plenty of boat builders that will supply you with an anchor so it is not necessarily so that they only intend these fixings to be used for moorings.

 

I'm confident about my anchor fixings:

Chunky! I hope that is not rusty at the bottom.

[carlt]

It may sheer off but so may a bolt fixing they won't take unlimited strain either. However, one of the advantages of using a rope is that the stretch of the rope will help to stop the strain snatching the fixing hard and of course it not likely that the anchor will grab hold of the bed immediately.

 

There are plenty of boat builders that will supply you with an anchor so it is not necessarily so that they only intend these fixings to be used for moorings.

 

 

Chunky! I hope that is not rusty at the bottom.

No, flaky paint (it's brass and not structural) the post goes all the way through the boat, though, the stern ones are about 4' long ant the bow ones 6' (at least).

[churchward]

No, flaky paint (it's brass and not structural) the post goes all the way through the boat, though, the stern ones are about 4' long ant the bow ones 6' (at least).

Ah yes of course it will be on your lifeboat won't it. Not much danger of breaking those without the whole boat coming apart first!

[Smelly]

Phil might be typing the same thing as me, but my main concern on the rivers that I've so far used is that if I deployed the anchor downstream of the boat, so as to make it swing around, then we may end up rolling against the bank as the arc is quite a wide one with my pride and joy travelling in it's most vulnerable position very quickly toward a shallow bit.

[PhilR]

Personally, I think a 15Kg Danforth anchor should be adequate for most narrowboats as long as there is a good length of HEAVY chain. My 12 metre chain weighs well over 1 cwt.

 

Fortunately, I have never had to deploy an anchor in an emergency situation, but I have the anchor at the stern when going downstream (or with the current) and at the bow when going upstream. The best place for the anchor chain and rope IMHO is coiled up in a bucket with the rope tied to a through bolted eyelet/T stud etc.

[mikevye]

There is almost certainly a conspiracy afoot!

 

Inclined to agree with you Carlt. Only just read this topic for the first time and the stern deployment makes the most sense to me. Assuming that the need to anchor the boat is in adverse conditions how many boats would have the front canopy unfurled allowing access to the front locker/anchor. There must be a cut off point somewhere when you wouldn't be on the river, too high, too fast flowing so apart from engine failure I would have thought the crew would have forewarning of a need to anchor anyway.

[DHutch]

INTERESTING. IS Carlt an administrator, am I treading on toes. His last post with regard to me has been added to with no mention of an edit ???

 

Carl is not an administer, a list of who is a moderator can be found here

 

What you have almost certainly witnessed is the facility called ‘automerge second post’ where by a second (or third, fouth,etc.) post made by the same user as the one preceding it is automatically merged with said preceding post if posted within 10minutes of the preceding post being posted. Its fairly standard practice on most large forums.

 

 

Daniel

[carlt]

Being a forum moderator would, of course, interfere with my role as BW mole

[ChrisPy]

really guys, you should know to defer to anyone with a title as important as international boatbuilder.

[RLWP]

Being a forum moderator would, of course, interfere with my role as BW mole

 

I thought that you were in league with the Forestry Commission

 

Richard

 

what with this stuff about wooden boats and all

[international_boatbuilder]

Carl is not an administer, a list of who is a moderator can be found here

 

What you have almost certainly witnessed is the facility called ‘automerge second post’ where by a second (or third, fouth,etc.) post made by the same user as the one preceding it is automatically merged with said preceding post if posted within 10minutes of the preceding post being posted. Its fairly standard practice on most large forums.

 

 

Daniel

 

Thanks for the clarification Daniel

[Thomas]

Never having ventured onto rivers with our NB I know nothing about anchors, so please excuse what may be a dumb question. Why do you have to have a length of both chain and rope? Why not just one or the other?

 

Thanks,

Tony

 

 

Hello everyone,

 

My first post!

 

The below might help explain why it is best practice to have a length of chain.....

 

For an anchor to "hold" it requires a horizontal pull along the bottom of the waterway. Ideally you would have enough anchor "line" paid out to allow for roughly three times the depth of water. The third of the paid out line nearest the anchor needs to be laying on the bottom, to provide the horizontal pull at the anchor stock. Having chain in this section helps considerably, as it tends to lay on the river bed.

The effectiveness of an anchor is dependant on this deployment. They are designed to dig in harder, the more horizontal pull is provided.

A small anchor, correctly deployed on a correct length line, with a chain length to the anchor stock, will be many more times effective than a heavy anchor on a short line, or one that does not have a suitable amount of chain to ensure the pull at the anchor is along the sea or river bed.

The above will also underline why its preferable to have a rope that has least tendency to float.

 

Best to be clear on the above, as when you deploy this piece of equipment it is often to because things are not going well, and to find it doesn’t work will only add to the likely depression caused by what has already turned out to be a rather bad day!

 

There may be times when you need to lift the anchor , or detach yourself from it, and if the boat has been riding hard against the cleat it can be extremely hard if not impossible to undo the rope. Practice on many rivers when this occurs is to tie a plastic can or float onto the line, with a suitable knot (check a knot book....it will show you the one to use!) and then cut the rope at the cleat, allowing the float to support the suspended rope. The rope will remain visible, tied to the float and it then enables the anchor to be recovered at a later date or when conditions permit, if this is practicable.

 

And finally, a stern anchor needs to be used with EXTREAM caution, and can be very dangerous. If when you venture out on a tideway or river you feel releasing the anchor from forward is not going to be possible, then consider bringing the anchor aft to the steerers position , with the end still secured to the fwd cleat , so that it can be deployed aft, but will hold the craft from fwd. Remember to "pay" out an anchor. a bundled coil of rope and chain wrapped around an anchor wont work well...and as for "throwing" the anchor overboard......as one who rather shamefully admits to having followed it over the wall when attempting to deploy by this method, I would suggest that whatever the emergency that requires you to use the anchor, keep your cool, and deploy with caution. If you are going out on river, then practice using you anchor before you go...after all, you will ensure that all your other boat skills are up to scratch before you leave...Surprising how many people have a boat, but have no idea how they would use an anchor if they really needed one!

 

Tha must enough on anchors...hello! hello!...... any one still awake...?

[RLWP]

Hello everyone,

 

My first post!

 

The below might help explain why it is best practice to have a length of chain.....

 

(snip)

 

Tha must enough on anchors...hello! hello!...... any one still awake...?

 

Hi Thomas,

 

welcome to the forum and thanks for an interesting post. I'm going to find a float for our anchor line.

 

Richard

[DHutch]

Its certainly true that having enough line, and or with some or all of that being chain, is as or more important as the size of the anchor involved. Which while mentioned, was indeed proberbly not given suffecent airing or explanation.

 

So while asking what size anchor, also consider the depth of water you will be sailing in.

 

That said, i still think 15kg is a bit small for a 60ft (15-20tonne) narrowboat. Not sure?

 

 

 

 

 

Daniel

[PhilR]

Its certainly true that having enough line, and or with some or all of that being chain, is as or more important as the size of the anchor involved. Which while mentioned, was indeed proberbly not given suffecent airing or explanation.

 

So while asking what size anchor, also consider the depth of water you will be sailing in.

 

That said, i still think 15kg is a bit small for a 60ft (15-20tonne) narrowboat. Not sure?

 

Daniel

 

 

It would be interesting to hear from anyone who has needed to deploy an anchor in an emergency situation on a narrowboat.

Edited July 28, 2009 by PhilR

[Philip]

For a 25ft steel narrowboat, which anchor weight would you go for? 

 

And is 4m of chain ok for the Thames?

[Tracy D'arth]

NO!  Not again, another anchor thread, after 11 years it has come back to haunt us.

 

Anchor, as big as you can handle easily, chain the same weight as the anchor. Warp  twice as long as the chain.

[Alan de Enfield]

26 minutes ago, Philip said:

For a 25ft steel narrowboat, which anchor weight would you go for? 

 

And is 4m of chain ok for the Thames?

 

Summary :

 

It is not all about anchor weight - a 7Kg anchor of one design will perform better than a 25kg of another design.

If using 100% chain you need a minimum of 3x water depth and preferably 5 times water depth, using insufficient chain results in achieving  a very low percentage of the potential anchor holding power.

If using 100% rope then you need an absolute minimum of 10 x water depth. using NYLON rope (or preferably lead cored anchor rope) (not other synthetics as they float)

You need a dedicated anchor strong point - using the T-stud on the bow will (porbably) rwsuklt in it being snapped off. It is not designed for shock loads.

 

 

 

Edit to add

Scope =  measured in anchor chain used Vs water depth, so 5x water deoth equals a scope of 5:1

 

 

 

 

 

26 minutes ago, Philip said:

And is 4m of chain ok for the Thames?

 

 

Only if the water is 2 feet deep.

Edited May 10, 2021 by Alan de Enfield

[David Mack]

57 minutes ago, Philip said:

For a 25ft steel narrowboat, which anchor weight would you go for? 

 

And is 4m of chain ok for the Thames?

No.

 

But as you will never deploy the anchor in anger it is a hypothetical question.

Lots of previous posts about anchor type, weight, warp length, attachment, which end of the boat to deploy from, how best to deploy etc. etc. But hardly any examples of where anyone has actually used an anchor in an unplanned situation. So read all the previous threads, get yourself thoroughly confused, then ask yourself how effectively you could deal with the situation when something goes unexpectedly t*ts up.

[LadyG]

On 23/07/2009 at 10:12, churchward said:

That's a good point about the anchor at the rear and of course essential if you are a single hander at least.

 

One other point to the OP is that it is best to consider the anchor and chain as a one shot throw away item. It can be very difficult to retrieve anchors depending on what is on the bottom of the river and can mostly only be done if held fast (as you hope it will be!) by pulling directly upward or a little back from the way it went in.

 

In any case if you can't get it back it will likely to have been £100 or so well spent as it could save your boat, you and your loved ones.

CRIKEY,  my anchor, chain and warp cost about £500 if I use it, I won't lose it.

I might have a mud weight on the stern, but then I've never been on the Thames. 

[Alan de Enfield]

15 minutes ago, David Mack said:

But as you will never deploy the anchor in anger it is a hypothetical question.

 

A very dangerous assumption - maybe correct to say 'in the unlikely event' but to say never is very misleading & totally wrong.

 

I know of several who have had to deploy their anchor on a River due to engine or gearbox failure, and I also know of at least one who didn't have an anchor to deploy and was swept over the weir after rolling under the Dolphins.

 

Maybe you also follow the policy of "I won't insure my house, it will never burn down or get damaged in a storm"