Shrewley tunnel....

[RLWP]

There isn't. But there are strongly circulating currents from rapidly dropping a deep wide lock-full into a short fat pound. It never fails to amaze me how Telemachus, which is barely affected by crosswinds, can suddenly go sideways at such a rate when transitting those pounds.

 

Really? So that air blowing on the side of my face - what's that then?

 

Richard

[WotEver]

 

Really? So that air blowing on the side of my face - what's that then?

 

Richard

That's Mrs Tawny Owl whispering sweet nothings in your ear.

[john6767]

Really? So that air blowing on the side of my face - what's that then?

 

Richard

There is no answer to that one

[archie57]

 

How strange. We moor not far from it and I have never heard it called Hatton tunnel. It's not near Hatton and is directly under Shrewley

 

Richard

Perhaps I should have said working boaters of the past!

[Athy]

 

How strange. We moor not far from it and I have never heard it called Hatton tunnel. It's not near Hatton and is directly under Shrewley

 

Richard

As the song from the film puts it, "You can keep your Hatton".

[RLWP]

That's Mrs Tawny Owl whispering sweet nothings in your ear.

 

From the gate of the lock ahead? I'm all for romance but bellowing sweet nothings across a lock pound?

 

Mind you...

 

Richard

Perhaps I should have said working boaters of the past!

 

I guess that makes sense. Hatton flight isn't close to Hatton. The tunnel is and Shrewley village wouldn't have much significance to them. Handy for a pint of milk if you were walking over the top maybe

 

Richard

[Guest]

Perhaps I should have said working boaters of the past!

 

That's pretty common then I believe, for some locations/structures to have different names from what they are known as now, or sometimes still.

[Heartland]

I record that William Fletcher was given the contract to build Shrewley Tunnel (1796), in Silent Highways. I do not recall any canal minute mention of the towpath tunnel, but mention of this might appear in records.

 

It is a subject worth following up, even if just to recheck the minutes..

 

Did Fletcher chose to add the towpath tunnel at first ? Was it his intention to take the towpath over the top and then found a shorter tunnel might suffice? or was there originally a path over the top?

 

Ray Shill

[nicknorman]

Really? So that air blowing on the side of my face - what's that then?

 

Richard

That is cross wind, or a farting sheep. But you said why is there ALWAYS a cross wind, the answer is that it isn't, but there is always a cross current if you have just drained the lock, and it persists for a surprisingly long time. Lots of stored energy in the circulating water. Edited January 31, 2016 by nicknorman

[RLWP]

I record that William Fletcher was given the contract to build Shrewley Tunnel (1796), in Silent Highways. I do not recall any canal minute mention of the towpath tunnel, but mention of this might appear in records.

 

It is a subject worth following up, even if just to recheck the minutes..

 

Did Fletcher chose to add the towpath tunnel at first ? Was it his intention to take the towpath over the top and then found a shorter tunnel might suffice? or was there originally a path over the top?

 

Ray Shill

 

Another interesting thing about Shrewley is how they approached handling ground water. There are several large openings in the north east wall of the tunnel towards the north end. They seem to lead to passages going into the rock then up the brick arch. I have never seen this in other tunnels

 

Some day I'll stop and have a look in one of them.

 

Richard

[___]

That is cross wind, or a farting sheep. But you said why is there ALWAYS a cross wind, the answer is that it isn't, but there is always a cross current if you have just drained the lock, and it persists for a surprisingly long time. Lots of stored energy in the circulating water.

Well if we are going to be pedantic about descriptions the energy in the circulating water is real not stored; that's why it causes you a problem. The same water had stored (potential) energy when it was in the lock above. Opening the paddles turned it into real (kinetic) energy.

 

Anyway back to Shrewley and my initial thoughts were that it is possibly a later addition. That's the normal case where railway tunnels have separate parallel bores. The other cause could be a geological consideration. Not convinced on the economics of being cheaper to drive two tunnels through the same hill even if one is shorter.

 

Jon

[nicknorman]

Well if we are going to be pedantic about descriptions the energy in the circulating water is real not stored; that's why it causes you a problem. The same water had stored (potential) energy when it was in the lock above. Opening the paddles turned it into real (kinetic) energy.

Jon

I think it is a matter of semantics but I would say that, for example, a spinning gyroscope stores energy as does a battery. Potential energy is not the only type of stored energy. All energy is real whether stored or not. Edited January 31, 2016 by nicknorman

[___]

I think it is a matter of semantics but I would say that, for example, a spinning gyroscope stores energy as does a battery. Potential energy is not the only type of stored energy. All energy is real whether stored or not.

 

Nick you are too clever for your own good!

 

However let's not get pedantic about the semantic of the technic(al) otherwise we will end up reconstituting the nb Beech thread and we don't want do that...

 

I was only really picking up on taking Richard's use of 'always' literally when I suspect you knew he meant it in an exaggerated sense.

 

Back to Shrewley.

 

Jon

[RLWP]

I was only really picking up on taking Richard's use of 'always' literally when I suspect you knew he meant it in an exaggerated sense.

 

Back to Shrewley.

 

Jon

 

Me, exaggerated? Never in a million years...

 

Richard

[nicknorman]

Nick you are too clever for your own good!

 

However let's not get pedantic about the semantic of the technic(al) otherwise we will end up reconstituting the nb Beech thread and we don't want do that...

 

I was only really picking up on taking Richard's use of 'always' literally when I suspect you knew he meant it in an exaggerated sense.

 

Back to Shrewley.

 

Jon

Fair enough but my point was not about "always" it was that the actual cause of the sideways push is mostly due to the current and not due to the wind, although I'll accept that since tawny only draws 3 inches it may be more affected by x-winds than Telemachus. Not sure how often you have done Knowle but if you are familiar with it you will know that boats always want to go sideways, and quite dramatically. This is often put down to wind even when its calm, I am just attempting to dispel the myth!

[RLWP]

To be honest, Nick. I have genuinely experience cross winds most times I have been up Knowle. Unless there is a current in the pound that flows uniformly from side to side between the locks

 

As Tawny does indeed only draw 3" (at the stern) and is otherwise a 70' sail I'm pretty well attuned to the effects of wind. If you meet us out and about you may spot the yellow burgee on the front mushroom to warn me of impending irregularities

 

I'm not denying the possibility of circulating currents in the pounds. As you say, that's a lot of potential energy being dumped into the pound and it has to go somewhere*

 

Richard

 

*I wonder if the temperature in the pounds rises?

[Victor Vectis]

Some day I'll stop and have a look in one of them.

Well, it's dark in those tunnels. Good opportunity for Sue to whisper sweet nothings in you ear 'ole.

 

[RLWP]

Well, it's dark in those tunnels. Good opportunity for Sue to whisper sweet nothings in you ear 'ole.

 

 

As it happens, darkness, moving water and machinery are the stuff of my nightmares, so I'm pretty much on edge at the tiller in tunnels as it is

 

Whispering in my ear is likely to lead to death by drowning or a heart attack!

 

Richard

[nicknorman]

To be honest, Nick. I have genuinely experience cross winds most times I have been up Knowle. Unless there is a current in the pound that flows uniformly from side to side between the locks

 

As Tawny does indeed only draw 3" (at the stern) and is otherwise a 70' sail I'm pretty well attuned to the effects of wind. If you meet us out and about you may spot the yellow burgee on the front mushroom to warn me of impending irregularities

 

I'm not denying the possibility of circulating currents in the pounds. As you say, that's a lot of potential energy being dumped into the pound and it has to go somewhere*

 

Richard

 

*I wonder if the temperature in the pounds rises?

Of course there are times of significant crosswinds and it is a bit exposed, but equally we have encountered major and unexpected sideways pushes even when it is flat calm. Put it like this I have never NOT had a major sideways push, and typically it comes from one side and just when you have corrected for that it comes from the other side (because you are traversing the circulation). If you watch a piece of flotsam you can often see it moving sideways rapidly in the current. Quite why it is so noticably at knowle I'm not sure, of course the locks are deeper and the paddles bigger than Hatton, but not by a massive percentage, so I also think it must be something to do with the shape of the pounds. It is something I've noticed at Hatton but to a much, much lesser extent.

 

And yes, the water will get a bit warmer. But still bloody cold if you fall in!

[RLWP]

Those pounds are quite well silted up making them sort of bowl shaped. It isn't unusual to find one of them empty.

 

They are also very wide for their length which Hatton isn't. You notice this walking from lock to lock - and I think this may be why!

 

The Knowle locks all sit in the middle of the pounds: https://www.google.co.uk/maps/place/Bottom+Lock+Cottage,+Kenilworth+Rd,+Knowle,+Solihull,+West+Midlands+B93+0JL/@52.3830278,-1.7238654,695m/data=!3m1!1e3!4m2!3m1!1s0x4870b6534852b391:0xf641eb8ac528b968!6m1!1e1

 

The Hatton locks are mostly at the sides of the pounds. If there is circulation going on, it would run parallel to the towpath at Hatton, from one lock to the other. At Knowle it would run across the lock exit and entrance

 

Richard

[Barry]

My first ever trip on a narrowboat was on a forum member's boat. I crewed for him for a fortnight.

 

First locks I ever did were the Knowle flight, going uphill

 

He was quite experienced I think but I remember distinctly him being caught out and doing a 360 in one of the pounds.

 

Most embarrassed he was.

 

 

 

 

Mind you I was also mightily embarrassed by, due to ignorance, turning one of the locks on an approaching boat. A lesson I never forgot

[furnessvale]

 

As it happens, darkness, moving water and machinery are the stuff of my nightmares, so I'm pretty much on edge at the tiller in tunnels as it is

 

Whispering in my ear is likely to lead to death by drowning or a heart attack!

 

Richard

Whatever you do, don't leave the dog on the slide. That sudden lick will do for you!

 

George ex nb Alton retired

[RLWP]

Whatever you do, don't leave the dog on the slide. That sudden lick will do for you!

 

George ex nb Alton retired

 

AAAaaarghhHHH!!!

 

Richard

[Tom and Bex]

Knowle locks are some of our least favourite locks. Not only is there always a strong cross wind but even if it's a nice calm sunny day when we set off from our moorings a few miles away it always rains. I don't think we have ever done Knowle locks in either direction in dry weather!

 

It also seems a long walk between locks due to width of the pounds. There's also never anyone to help with gates etc at Knowle unlike Hatton and Lapworth, and rarely any other boats to pair up with.

[Victor Vectis]

Knowle locks are some of our least favourite locks. Not only is there always a strong cross wind but even if it's a nice calm sunny day when we set off from our moorings a few miles away it always rains. I don't think we have ever done Knowle locks in either direction in dry weather!

Is the wind cross because people confuse it for a circulating current?

 

 

(I quite like the Knowle flight, BTW. And how long has the paddle at the top left of the top lock been out of action?)