Anchor

[Doug Scullery]

Excellent, thanks. And now that I know what a warp is (not something from star-trek), I have 2 more questions: 1. why is it called a warp? and 2. can I use a spare mooring line?

 

1. No idea and 2. Yes, but I don't. The theory being that it's the last rope I want to become weak from wear and tear

[Dorlan]

Was that picture taken at Calcutt? If so is the boat still there with the anchor like that?

Yes, and it was when I saw it a week or so ago!

[larryjc]

There's alot of questions I had about anchors when I took a river mooring about a year ago and decided it was time for a "proper" anchor (I got a 15kg grapnel anchor and a couple of meters of flimsy chain with the boat, definitely not enough). Bear in mind here that I have absolutely no experience using an anchor, I've just tried to follow the best advice I can find on what to have and how to use it in an emergency. Danforth is definitely the type I have usually been recommended, apparently it's a good multi tasker when it comes to digging into different surfaces, which is what you want when travelling on river. I'm still a little unsure what the ideal requirements to attach the warp (rope, from the end of your chain to the boat) to the boat are, there are scare stories about T-studs snapping under the load and some people recommend having something bolted through the steel of the hull. I don't have that, but the bollards on my boat are chunky (what I assume if a short length of 2"-3" diameter steel tube welded to the gunwhale with a little egg shaped sheet steel cap welded on top, that's what it looks like, anyway) and I hope that the scare stories I've heard are about the T-studs you see that are basically a T shape of 1"ish steel bar welded onto the gunwhale. I have been told that the correct way to deploy it is to slowly lower it by hand and wait for it to "bite" before tying the warp off at an appropriate length, not sure how easy it is to judge that process for the first time in an emergency situation so I always have the end of my warp looped over a bollard so if the worst comes to the worst and someone panics and just chucks it overboard, at least it's attached to the boat. As for recovering the anchor you've got it spot on, from what I've heard, it's all about pulling the anchor in the opposite direction that the boat was pulling it in the wind/current. The other thing you need to bear in mind is the total length of your warp+chain combined, I've been told that you want 6 times the maximum depth of the water you're in, which I believe can vary quite a bit river to river. For the Avon (as far as Bristol, not into the channel) I have been told that over 25m is ideal, so I've ended up with 17m of rope and 13m of chain. A friend who is setting off from Bristol to Sharpness soon was recommended quite a bit more, I believe they've ended up with 30m of rope and and 10m of chain, but it might be even more than that.

 

Never anchored a canal boat but done it over 300 times in a yacht and never dragged. Scope is generally a minimum of 3 times the depth if using chain and 5 times if using rope. That might be enough to stop you in an emergency but it is a minimum and if you have more - use it. What you are trying to do is keep the anchor lying flat or with shank pulled up at an angle of less that 15 degrees as beyond that it will pull out. So the more and heavier line you have out the more the line will tend to pull along the riverbed rather than upwards to the boat. Anchor chain is doing nothing if still on the boat.

 

As for lowering it by hand and waiting of it to bite - seems a recipe for being pulled over the side or getting your fingers or feet trapped! Assuming its an emergency I would chuck all I had over the side having made damn sure it was tied on securely first. If you have some nylon that will stretch a bit and act as a shock absorber if the bite is a sharp one.

 

When you recover it, motor towards the anchor and pull in the slack by hand. Lugging twenty tons of steel forward against a current is not going to be easy. When it is starting to become vertical it may well pull out (15 degrees). If not then tie it off an tug it free with the motor.

[DandV]

Scope is generally a minimum of 3 times the depth if using chain and 5 times if using rope.

 

So what maximum depths of water would a narrowboat encounter on the system, including tidal rivers? The system being defined as passages without requiring insurance extensions?

What proportion of chain weight to anchor weight? For the same weight of chain, is it better to have a short length of heavy chain, or a longer length of lighter chain?

 

Don

Edited April 1, 2013 by DandV

[larryjc]

So what maximum depths of water would a narrowboat encounter on the system, including tidal rivers? The system being defined as passages without requiring insurance extensions?

What proportion of chain weight to anchor weight? For the same weight of chain, is it better to have a short length of heavy chain, or a longer length of lighter chain?

 

Don

 

I'm guessing but expect other would know but I would think about ten metres in the bigger rivers. As to chain to anchor weight that's not really the issue. Most anchors are rated against size of vessel, but generally that's for yachts. So an 18kg Delta is good for boats up to 55 feet for example. You would have to ask the manufacturers what variance might be applicable to narrow boats. As for chain - heavier chain is safer both because of its weight and its going to be stronger. I don't think there is much guidance about how much chain you use depending on the weight of it. Most people use 8 or 10mm. Personally on my boat I am going to use rope. As this thread has already discussed its sensible to have the anchor at the upstream end of the boat and lugging large quantities of chain from one end of the boat to the other doesn't seem a good idea.

[DandV]

I think there is a fundamental difference between the anchoring requirements of open water craft with which I am familiar, and narrowboats which I am not.

In open water craft the prime purpose of the anchor is to provide secure, generally overnight or longer term mooring. Wind load is often very significant and often wave height is an issue. Chain attached to the shank keeps the pull parallel to the bottom and the partial lifting the anchor chain provides cushioning to limit snatch. If the chain is longer then the depth of water then the retrieval load is reduced by the amount of chain already on board a significant advantage for manual retrieval.

 

For a narrowboat the anchor is purely an emergency device to be deployed to stop an underpowered or unpowered boat being driven by largely water flow on to an obstruction, or out to sea. They have comparatively little windage. My own non narrowboat anchoring experience suggests that a weight of chain attached to the shank is more effective then increasing the anchor weight by the same amount for the reasons stated before. Also the smaller anchor combined with a length of chain is easier to store. If the risk is going ashore in shelving conditions then some anchor drag until the line developed enough angle to hold would be acceptable but not upstream of a weir or bridge pylon.

 

Don

[larryjc]

I must agree and have yet to try it - in fact I hope never to do so!

[Grace and Favour]

I must agree and have yet to try it - in fact I hope never to do so!

 

We have taken the precaution of fitting a hefty anchor and windlass to our boat as one of the key safety measures prior to cruising on the Trent. (We also equipped ourselves with life-jackets, VHF and even a rope ladder)

 

The first week we were on the Trent, half way between Cromwell and Nether locks, a joint on the hydraulic steering 'popped' - resulting in immediate loss of steerage, within a few seconds the flow was turning us broadside.

 

The sensation was rather unpleasant and worrying, (with visions of being washed against the rather fast running weir at Cromwell!)

 

We calmly had our first deployment of anchor procedure - - (with my First Mate correctly remembering which foot switch to use on the windlass) - anchor dropped and we fed out chain, about 20m - and came to an halt.

 

Phew!

 

That enabled us to determine what the problem was, fit the 'emergency' tiller, re-commence steering and recover the anchor (slowly driving along the line of the anchor chain whilst First Mate operated the windlass - until the chain was nearly vertical and the anchor broke free).

 

All in all, an unexpected adventure, that we handled well - - but it was a first-hand lesson that taught us to always be prepared for all eventualities.

 

And are we relieved that we did equip ourselves with an (over-spec) anchor

[Phoenix_V]

We have taken the precaution of fitting a hefty anchor and windlass to our boat as one of the key safety measures prior to cruising on the Trent. (We also equipped ourselves with life-jackets, VHF and even a rope ladder)

 

The first week we were on the Trent, half way between Cromwell and Nether locks, a joint on the hydraulic steering 'popped' - resulting in immediate loss of steerage, within a few seconds the flow was turning us broadside.

 

The sensation was rather unpleasant and worrying, (with visions of being washed against the rather fast running weir at Cromwell!)

 

We calmly had our first deployment of anchor procedure - - (with my First Mate correctly remembering which foot switch to use on the windlass) - anchor dropped and we fed out chain, about 20m - and came to an halt.

 

Phew!

 

That enabled us to determine what the problem was, fit the 'emergency' tiller, re-commence steering and recover the anchor (slowly driving along the line of the anchor chain whilst First Mate operated the windlass - until the chain was nearly vertical and the anchor broke free).

 

All in all, an unexpected adventure, that we handled well - - but it was a first-hand lesson that taught us to always be prepared for all eventualities.

 

And are we relieved that we did equip ourselves with an (over-spec) anchor

 

Which end and which direction and what weight/type

[NickF]

When I went up the Thames from Limehouse with a RYA instructor on board he suggested it was at the upstream end of the boat so we had it at the stern as we were traveling with the tide and fixed it to the starboard dolly, That way when deployed you would not spin round but swing slightly to starboard and hence away from oncoming or overtaking boats. I hasten to add we didn't have to use it and it was extremely heavy to move from bow to stern.

[Grace and Favour]

 

Which end and which direction and what weight/type

We have our anchor (an Halls 36Kg (!)) at the bow running through an anchor pipe from a chain locker, and hauled with a Lewmar winch.

We've 40m of 10mm short-link calibrated chain. (the chain weighs 110Kg!)

 

I know I've over-specified, but our boat weighs 36 tonne - and I'd rather over-spec than under-spec

Edited April 9, 2013 by Grace & Favour

[Naughty Cal]

We have our anchor (an Halls 36Kg (!)) at the bow running through an anchor pipe from a chain locker, and hauled with a Lewmar winch.

We've 40m of 10mm short-link calibrated chain. (the chain weighs 110Kg!)

 

I know I've over-specified, but our boat weighs 36 tonne - and I'd rather over-spec than under-spec

Ours is also heavily over specced (as standard, thanks Sealine) but I would rather it was that way then well under specced.

 

We have a 10kg Delta anchor and 40m of 10mm chain for a 25ft cruiser all hauled in and launched by a Lewmar electric winch. It weighs a lot but we use it on a regular basis and it has not let us down yet in a wide range of bed conditions from nice a nice sandy bottom through to soft mud and weed. Its nice to know you can rely on your anchor.

 

This was last weekends chosen anchoring spot.

 

 

Great spot to spend the weekend but you do need a dinghy to get to the pub and the shops.