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Anchor/rope/chain etc. for Tidal Thames


Ewan123

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43 minutes ago, Tony Brooks said:

OFF TOPIC - or nearly.

 

If the OP is going to be mixing it with trip boats and tugs I would be just as concerned about the state of the fuel tank. At the least syphon or pump any muck, water & emulsified fuel from the bottom of the tank and fit a new set of fuel filters. Also carry spair filters and know how to change them and bleed the engine.

That's it @Tony Brooks one has to weigh up one consideration with another, and having a well maintained boat is a major factor.

I threw away thirty litres out of sixty five litres of diesel when I first got the boat, not much actual water, just twenty years of crud.  It took a day or three to do this with containers and pump from Aldi as I recall. I generally buy diesel from reputable sources!

I can pick and chose when I travel, but if permanently on a tidal river, I'd be fitting an extra filter, or cleaning tank every year.

 

 

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5 hours ago, blackrose said:

You'll need a lot more than 5m of 8mm chain. More like 15m of 10mm chain plus 20m of decent rope. 

 

4 hours ago, LadyG said:

He wil then struggle to retrieve the ground tackle.

A boat which uses chain for mooring will have a chain locker, hawse pipe and a proper feed to anchor, and  a windlass with calibrated chain. The design of the bow will allow for retrieval.

Emergency deployment on a river eg engine failure, the anchor needs to hold quickly in unknown holding ground. This is one reason why a modern anchor may be better than a massive Danforth, and I'm not convinced about quick holding with a plough, having had experience of them in yachts.

The boat will be doing its own thing, so the crew need to get the anchor down fairly quickly, and make the rope fast to the T piece, it will not be easy to  handle chain from a well deck,  and trying to make make chain fast to the T piece might result in lost fingers., therefore the chain could be shorter than for mooring, five or six metres of heavier chain would be my choice with a big narrowboat, maybe ten with a big widebeam.

If the boat has stopped and the anchor dug in, then one needs to assess how much cable is required, with no other restriction, then three times depth is about right for a boat in good weather. On a tidal river after emergency, one needs to be more circumspect, take in to account depth of water at high tide, current, wind, forecasts, tide direction, other boats, or obstructions, proximity to banks, river bed profile any likely commercial traffic, rescue facility.

The boat will likely snatch, putting a lot of strain on the T piece. When it takes up and snatches the crew is best to stand well back and trust that his method of laying out the rope is fankle free, knots weaken rope by as much as fifty percent.

The crew should know how to tie a rope to the T piece cleat.

A lot depends on what is happening, but one envisages the anchor being dropped in, the chain will follow fairly quickly, but if the boat is stationary do not let the chain land in a heap on top of anchor. The crew wil feed rope through their hands, if the boat is still moving best to take one turn on the T to exert control. The end of the rope may not be secured to the boat, if this is the case, make it fast on the T when you have at least two  metres in hand. Do this with two round turn ,then cross over one horn, then lock over the other horn. See YouTube for demo.

 

 

(to the bit in bold) Not really. On recovery, the length of chain being lifted at one time is just a bit more than the depth of water, i.e. in 10 foot water depth, you'd only be lifting about 12 foot of chain, and its weight is reduced by its buoyancy.

 

"Dropping" the anchor is probably a bit of a misnomer : thinking of the process as lowering might be better. The thing to avoid is chucking an anchor and a heap of chain over the side, which is a recipe for an anchor fouled by its chain.

 

3 times water depth is very much a bare minimum, and remember that "water depth" includes the height of the gunwale above water level. 

 

A turn of the rope around the T stud is a good method of retaining control of  the anchor rope, and avoiding a sudden jerk when (if!) the anchor bites. A rope that will happily hold a boat stationary against full engine power will easily snap if used to bring a boat to a sudden stop.

 

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3 minutes ago, Iain_S said:

3 times water depth is very much a bare minimum, and remember that "water depth" includes the height of the gunwale above water level. 

 

 

Indeed at 3x the depth the anchor is only performing at 53% of it full holding power, and if you have a pathetically low holding power anchor to start with then you have very little chance.

 

I'd always plan to use a minimum scope of 5:1 with 100% chain and more if it was a chain / rope combination.

 

 

 

Effect Of Scope.png

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As has been said in the thread a couple of times the design of anchor is of as much importanceas the weight, an interesting article :

 

Rememeber that for 'normal boating' the anchoring is planned and controlled, and if it doesn't work first time we can re-set the anchor again and again, and there is no shock load applied, the engine is used to slowly set the anchor and then the load is steady and 'fixed'.

With a NB with engine failure on a river, it is a "must work 1st time" scenario and there is a '20 tonne' shock load applied when the anchor sets.

 

Numerous tests carried out throughout the world have demonstrated that the geometric proportions of the anchor are more important than its actual weight. Anchors of recent construction, such as the Kobra, bites into the seabed within seconds due to its weighted tip and holds very well thanks to its broad shoulders. Tests carried by French magazines Voile Magazine and Moteur Boat Magazine gave clear evidence that ”a 6 kg Kobra anchor held a 600 kg traction load, in a mixed sand-mud seabed”, which corresponds approx. to the traction exerted by a 42-knot wind on a 9 m boat, where a 12 kg anchor is traditionally recommended.

 

Now we get to the "I couldn't lift a 30kg anchor argument"

I bet you could when the adrenalin flows you'd be surprised. I had a winch failure and had to pull in 300 feet of 10mm chain and a 30kg anchor (by hand) in 30 feet of water Its surprising what can be achieved (but my back ached the next day)

 

 

 

Screenshot (1267).png

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6 minutes ago, Alan de Enfield said:

Rememeber that for 'normal boating' the anchoring is planned and controlled, and if it doesn't work first time we can re-set the anchor again and again, and there is no shock load applied, the engine is used to slowly set the anchor and then the load is steady and 'fixed'.

With a NB with engine failure on a river, it is a "must work 1st time" scenario and there is a '20 tonne' shock load applied when the anchor sets.

Surely people don't just heave the whole lot over the side and hope for the best.

In an emergency I would hope that I would take a turn on one of the bits and once a decent length of warp has gone out tighten the turn until the anchor has set and then make fast.

Edited by Loddon
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5 minutes ago, Loddon said:

Surely people don't just heave the whole lot over the side and hope for the best.

 

If they have not been educated 'not to' then they often do.

 

5 minutes ago, Loddon said:

In an emergency I would hope that I would take a turn on one of the bits and once a decent length of warp has gone out tighten the turn until the anchor has set and then make fast.

 

If you have no power then this is the best you can do - but it is a good idea to have chain / rope markers at (say) 1(or maybe 5) metre intervals so you know you have let out sufficient to have a good catenary (scope)

Edited by Alan de Enfield
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Fifteen metres of 5/16 chain plus thirty metres of 18mm nylon I could stop it pretty much anywhere once half the nylon is out and that would be ok. Chain is stored in a sacrificial bucket and the nylon is fig8 in its own open locker so its obvious how much is left.

 

Danforth work well on the East Coast Rivers😉

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37 minutes ago, Alan de Enfield said:

 

 

And then you say ...............

 

Remember I may well be taking the Mick / making fun 😱

But not always!

Remember the East Coast rivers (Crouch, Roach and Blackwater) have muddy bottoms. I have spent a good few nights at anchor out there on a Danforth and can only think of one night when the anchor dragged and that was only a few yards.

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23 hours ago, Alan de Enfield said:

 

 

The breaking stain of 12mm Nylon rope is ~3000kg, does anyone really think that will hold the shock-load of a steel NB ?

 

 

22 hours ago, Alan de Enfield said:

If you want to do it properly than make an anchor fixing point, do not rely on the T-Stud as they have been known to shear off under shock-load, you then end up with no anchor and no means of stopping.

 

Drill a 1/2" hole whever you want the fixing.

Get a 12mm eye-bolt.

METRIC A4 STAINLESS STEEL SHORT EYE BOLT | eBay

 

 

That size of eye bolt has a working load of around 300-400kg.  Even with a safety factor of, say, 10, it is little stronger than the 12mm nylon rope you derided.

 

 

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I have fond a case of a Narrowboat deploying an anchor, I don't know if it worked.

 

31st May 2022
New Lifeboat Helm’s first service in command brings 2 men and a dog to safety
Broken down canal boat aground in the River Douglas
Lytham St Annes Lifeboat Station’s latest Volunteer Inshore Lifeboat (ILB) Helm completed a tricky job in his first service in command. Will Bridge qualified as a Helm (the Volunteer crew member in command of the ILB), at the end of April 2022 after dedicated and rigorous training. His first service in charge of the ILB occurred on Tuesday 31st May 2022 when a 42 foot (12.8m) canal narrow boat broke down and as a result ran aground in the River Douglas.
The Lifeboat Volunteers were paged at 1:22pm and the ILB set off in a choppy sea to find the casualty which had been reported as aground at the Millennium Link canal which joins the Ribble to the Lancaster Canal. Will’s crew in the ILB were Nigel Browning, Elizabeth Gee and Clive Holland.
With no sign of the canal boat at the Millennium Link, further information came in from Preston Dock that the vessel had left there to head toward the Leeds-Liverpool canal which joins the River Douglas at Tarleton. Using his expertise and local knowledge, Will decided the logical place to find the canal boat was therefore in the River Douglas and this proved to be the case. The boat was found with an anchor out over her stern and her bow aground, fighting the fast ebb tide then surging down the Douglas.
In the difficult conditions, the Helm took the ILB MOAM alongside and transferred Lifeboat Crew Clive Holland across to assist the vessels two occupants. The ILB was then moved to the bow of the casualty to attach a line. This allowed the boat’s bow to be pulled into the channel and afloat. Once this had been achieved the anchor was recovered and the ILB took up the tow, upriver against the ebb tide, to the Douglas Boatyard at Hesketh Bank.
After safely mooring the casualty and ensuring her crew were now OK, the ILB took back Crewmember Clive before heading home to Lytham to be recovered by the Shore Crew shortly after 4pm. She was then returned to her boathouse to be checked, washed and refuelled.
A spokesman said, “It was an excellent service by Will in his first time in command of the ILB on a rescue. All his time, hard work and dedication to achieve this position has paid off and the Station now has yet another excellent Volunteer Helm.”.
 
 
 
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On 30/05/2022 at 08:18, LadyG said:

He wil then struggle to retrieve the ground tackle.

A boat which uses chain for mooring will have a chain locker, hawse pipe and a proper feed to anchor, and  a windlass with calibrated chain. The design of the bow will allow for retrieval.

Emergency deployment on a river eg engine failure, the anchor needs to hold quickly in unknown holding ground. This is one reason why a modern anchor may be better than a massive Danforth, and I'm not convinced about quick holding with a plough, having had experience of them in yachts.

The boat will be doing its own thing, so the crew need to get the anchor down fairly quickly, and make the rope fast to the T piece, it will not be easy to  handle chain from a well deck,  and trying to make make chain fast to the T piece might result in lost fingers., therefore the chain could be shorter than for mooring, five or six metres of heavier chain would be my choice with a big narrowboat, maybe ten with a big widebeam.

If the boat has stopped and the anchor dug in, then one needs to assess how much cable is required, with no other restriction, then three times depth is about right for a boat in good weather. On a tidal river after emergency, one needs to be more circumspect, take in to account depth of water at high tide, current, wind, forecasts, tide direction, other boats, or obstructions, proximity to banks, river bed profile any likely commercial traffic, rescue facility.

The boat will likely snatch, putting a lot of strain on the T piece. When it takes up and snatches the crew is best to stand well back and trust that his method of laying out the rope is fankle free, knots weaken rope by as much as fifty percent.

The crew should know how to tie a rope to the T piece cleat.

A lot depends on what is happening, but one envisages the anchor being dropped in, the chain will follow fairly quickly, but if the boat is stationary do not let the chain land in a heap on top of anchor. The crew wil feed rope through their hands, if the boat is still moving best to take one turn on the T to exert control. The end of the rope may not be secured to the boat, if this is the case, make it fast on the T when you have at least two  metres in hand. Do this with two round turn ,then cross over one horn, then lock over the other horn. See YouTube for demo.

 

 

 

Why would he struggle to recover it? I've put out a similar chain/rope warp and had no problem recovering it. Anyway the point is the primary reason for dropping an anchor is to stop the boat in an emergency (not for mooring!) and recovery of the anchor and warp is secondary.

 

You seem to be suggesting just using rope, in which case you know much less about anchoring than you're pretending. In fact your post is full of errors & misunderstandings. If you don't know what you're talking about on a subject it's probably better to ask questions or just not post at all. 

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11 minutes ago, Alan de Enfield said:

It seems a strange way of 'anchoring'  - 'run the bow ashore then throw the anchor out at the back', but 'hey ho' if it worked .............

Its not as if, with the bow run aground, on the ebbing tide its going anywhere (for a few hours anyway).

Unfortunately the full story on how he got into that position is not there. Was he running with the flow and put the anchor over the stern and then the tied turned? Did he put it out to stop it slewing round? It all sounds very strange, he had engine problems and turned back to the L&L?

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9 hours ago, blackrose said:

 

 

You seem to be suggesting just using rope, in which case you know much less about anchoring than you're pretending. In fact your post is full of errors & misunderstandings. If you don't know what you're talking about on a subject it's probably better to ask questions or just not post at all. 

Try reading all the posts.

I am not talking about mooring, I am talking about stopping a boat on a river with ground tackle which has to be handled by complete novices and in a boat not designed for deployment or recovery.

I've anchored more times than any posters on here, from pram dingies to seventy footers.

I don't post personal attacks on here, but that does not stop me having an opinion about certain people who have nothing better to do than sit and snipe.

Edited by LadyG
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On 30/05/2022 at 11:04, Ewan123 said:

 

Oh there was something else that popped out to me in there - I was planning to have a soft spliced loop on the end of the rope that will just sit around the T-stud ready for deployment. Assuming the T-stud is strong enough (I know, no guarantee) would you suggest tying to the stud to be better/worse?

A good long splice should be as strong as the original. I prefer the idea of a hard eye splice on the chain end, so that the rope is still available for other purposes eg deep locks or mooring in a gale, or winding.

The other end of the rope can then be controlled as it runs out, however this assumes free access to the T, if there is any doubt, or if the crew is untrained in rope handling, then using a soft eye splice would be a good idea. If there is big eye, you can tie a bit of string to stop it popping off. We are assuming  crew plops the anchor in to water from welldeck, chain follows automatically, then the rope feeds out of a bucket, having been carefully laid in the bucket. If no bucket is available the rope can be coiled on the floor of the well deck. The soft eye splice over T makes the system foolproof.

On 30/05/2022 at 11:04, Ewan123 said:

 

Oh there was something else that popped out to me in there - I was planning to have a soft spliced loop on the end of the rope that will just sit around the T-stud ready for deployment. Assuming the T-stud is strong enough (I know, no guarantee) would you suggest tying to the stud to be better/worse?

A good long splice should be as strong as the original. I prefer the idea of a hard eye splice on the chain end, so that the rope is still available for other purposes eg deep locks or mooring in a gale, or winding. I don't think there is much in it with crew used to handling ropes and boats.The other end of the rope can then be controlled as it runs out, however this assumes free access to the T.

If there is any doubt, or if the crew is untrained in rope handling, then using a soft eye splice would be a good idea. If there is big eye, you can tie a bit of string to stop it popping off. We are assuming  crew plops the anchor in to water from welldeck, chain follows automatically, then the rope feeds out of a bucket, having been carefully laid in the bucket. If no bucket is available the rope can be coiled on the floor of the well deck. The soft eye splice over T makes the system foolproof.

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On 30/05/2022 at 13:12, Loddon said:

Surely people don't just heave the whole lot over the side and hope for the best.

In an emergency I would hope that I would take a turn on one of the bits and once a decent length of warp has gone out tighten the turn until the anchor has set and then make fast.

The trouble is that the crew may be panicking, or untrained or have absolutely no wish to be involved. A lot of boaters are not able to handle ropes, they may not have much strength, or just have no idea, I see them every day, if they handle ropes they always end up with granny knots, or even a figure of eight, as I was handed the other day, lol.

Is it better to have a foolproof system of deployment, or a better system, but requires more user input.

There is also the problem clear access to the T in some boats.

I believe most people think the rope should be in a bucket, experience tells me the bitter end should be attached to something!

If the user is feeding the rope through his hands, it would be better if soft and maybe 12mm might be a bit small, but this bucket system is not the best if the user is to feed it out through his hands via the T. Having thrown the anchor in, the chain will follow quickly, the user then has to feed the rope, but at some time put a turn round the T post.

PS under no circumstances use the flat tape on a reel which is still being sold as suitable for anchoring, this will cut through flesh like a knife through butter.

Edited by LadyG
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5 hours ago, LadyG said:

Try reading all the posts.

I am not talking about mooring, I am talking about stopping a boat on a river with ground tackle which has to be handled by complete novices and in a boat not designed for deployment or recovery.

I've anchored more times than any posters on here, from pram dingies to seventy footers.

I don't post personal attacks on here, but that does not stop me having an opinion about certain people who have nothing better to do than sit and snipe.

 

You've anchored more times than any posters on here? Really? That's a big claim. I'm sorry but I'm not going to read all your posts if you're talking nonsense. 

 

I wasn't previously sniping and I made no personal attack. I was merely responding to your post where you told me that my advice to the OP to use a combination rope & chain warp couldn't be easily recovered. As I said, anchoring isn't about recovering the anchor, it's primarily about stopping the boat before it hits a bridge, goes over a weir, etc. 

 

If you think an anchor with only a rope warp will stop a narrowboat on the tidal Thames you're seriously misguided. Have you actually taken a boat on the Thames tideway? It's the chain that allows the anchor to bite, without a chain the anchor will just be pulled upwards and drag along the bottom. It might slow the boat a bit but it's not going to stop it on a 6 knot current. 

 

With all your purported anchoring experience I'm surprised you don't know the basics. 

Edited by blackrose
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1 minute ago, blackrose said:

 

I wasn't sniping and I made no personal attack. I was merely responding to your post where you told me that my advice to the OP to use a combination rope & chain warp couldn't be easily recovered. As I said, anchoring isn't about recovering the anchor, it's primarily about stopping the boat before it hits a bridge, goes over a weir, etc. 

 

If you think an anchor with only a rope warp will stop a narrowboat on the tidal Thames you're seriously misguided. Have you actually taken a boat on the Thames tideway? It's the chain that allows the anchor to bite, without a chain the anchor will just be pulled upwards and drag along the bottom. It might slow the boat a bit but it's not going to stop it on a 6 knot current. 

 

With all your purported anchoring experience I'm surprised you don't know the basics. 

 

It is interesting that the scope makes such a difference to the actual performance of the anchor, take a poorly performing anchor (Danforth) and use insufficient chain and you are then expecting a 20 ton boat to be held by 35% - 50% of a 'very low starting figure'.

 

 

 

Effect Of Scope.png

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T stud should have nothing to do with anchoring😉 I use the bit attached behind the front board to control the warp whilst the bitter end is attached to an eye on the front deck 

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3 hours ago, blackrose said:

 

You've anchored more times than any posters on here? Really? That's a big claim. I'm sorry but I'm not going to read all your posts if you're talking nonsense. 

 

I wasn't previously sniping and I made no personal attack. I was merely responding to your post where you told me that my advice to the OP to use a combination rope & chain warp couldn't be easily recovered. As I said, anchoring isn't about recovering the anchor, it's primarily about stopping the boat before it hits a bridge, goes over a weir, etc. 

 

If you think an anchor with only a rope warp will stop a narrowboat on the tidal Thames you're seriously misguided. Have you actually taken a boat on the Thames tideway? It's the chain that allows the anchor to bite, without a chain the anchor will just be pulled upwards and drag along the bottom. It might slow the boat a bit but it's not going to stop it on a 6 knot current. 

 

With all your purported anchoring experience I'm surprised you don't know the basics. 

At no time did I suggest no chain.

I said I prefer a shorter bigger chain for this particular use, part of the reason being that chain ends are half the price of chain by the metre. Mooring a yacht is not stopping a narrowboat..

My ground tackle cost about £500, I don't think anyone pottering on ditches need spend that much, I don't think they would anyway.

OK 1964, approx  twenty five nights at anchor, on the Clyde.

1965  ditto.

Pretty much the same for next ten years.

and so on for next fifteen years.

I've moored from Stornoway to Ile de France, , worse was Isle Oronsay, three nights of gales, anchor watch all night, but we never moved. 

 

 

 

1966 trip to Outer Hebrides

 

 

 

 

 

 

 

Edited by LadyG
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On 30/05/2022 at 12:38, Iain_S said:

 

(to the bit in bold) Not really. On recovery, the length of chain being lifted at one time is just a bit more than the depth of water, i.e. in 10 foot water depth, you'd only be lifting about 12 foot of chain, and its weight is reduced by its buoyancy.

 

"Dropping" the anchor is probably a bit of a misnomer : thinking of the process as lowering might be better. The thing to avoid is chucking an anchor and a heap of chain over the side, which is a recipe for an anchor fouled by its chain.

 

3 times water depth is very much a bare minimum, and remember that "water depth" includes the height of the gunwale above water level. 

 

A turn of the rope around the T stud is a good method of retaining control of  the anchor rope, and avoiding a sudden jerk when (if!) the anchor bites. A rope that will happily hold a boat stationary against full engine power will easily snap if used to bring a boat to a sudden stop.

 

It's handy to recover ground tackle if first attempt fails, in fact it's imperative

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9 hours ago, LadyG said:

............................................................

I've anchored more times than any posters on here, from pram dingies to seventy footers.

..............

That's very debatable. 

 

Howard

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On 29/05/2022 at 14:12, Ewan123 said:

I thought I'd ask a novel question that's never been answered before..! (I've been confused by the variety of previous answers and variety of previous boat specs.)

 

We'll be taking our 62ft steel narrowboat on the tidal Thames from Limehouse to Brentford. We currently have (on the boat when we bought it):

  • 15kg plough anchor
  • 5m of 8mm chain
  • 20m tatty blue polypropylene rope

 

I'm replacing the length of tatty blue polyprop and considering the below - I'm not too worried about how it feels in the hand as it's only a very occasional piece of emergency kit and if I can store it away more easily in between then that's no bad thing. 

 

https://www.buyrope.co.uk/30m-white-nylon-anchor-rope-12mm-thick/

 

So we'd end up with:

  • 15kg plough anchor
  • 5m of 8mm chain
  • 30m of 12mm rope

 

Is this in the right ball park or am I way off? I can see that it does slightly improve on the PLA's recommendations, though those are obviously pretty generic ("minimum of one 12kg anchor, attached to a designated strongpoint by 5 metres of 6mm short link chain and 25m of 12mm rope")

Just go with that and cross your fingers that you never have to test it, which is unlikely if you have clean fuel and a good engine.

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