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What happens to boat speed in tunnels / shallow / narrow sections?


Canal Runner

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Do you really have so little imagination?

 

 

1) You want to get to the pub before it closes

2) You want to get to the pub before they stop serving food

3) You want to get to your mooring before nightfall

4) You need to get back to the hire base by close of trading or lose your deposit

5) You need to get past the three week CRT stoppage starting in the morning

6) You need to get back to your mooring as you have to get to your car to go to work in the morning

7) You're low on diesel and the yard two miles away closes in half an hour and it's closed on Mondays (tomorrow)

8) You need to get to the railway station to catch the last train back to where you left the car

 

 

Any more reasons to be boating to a deadline, anyone?

 

When I'm boating its rare not to be trying to get somewhere by some particular time or other!

 

I can think of a number of reasons to be in a hurry.

 

One of your dogs is desperate for a leak and there's nowhere to get into the side.

 

You're on that evil smelling section of the North Oxford

 

You're trying to make the 3pm cut off for Harecastle tunnel and the boat in front has held you up several times once to salvage a plastic bag from the canal FFS, then "ooh I must take a photograph of that" without pulling into the side.

 

It's getting dark and you know there's only one decent mooring spot left at Fradley.

 

Crikey that couple we just shared a lock with were a bit weird weren't they...

 

You're navigating the Wigan flight.

 

You're in Blackburn, Nuneaton, Ashton (insert your own selection here)

 

You're on the Bridgewater expressway, yesssss....

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>> One of your dogs is desperate for a leak and there's nowhere to get into the side.<<

 

Forgive my ignorance, but can't canines be persuaded to have "just in case wees", like children?

 

Meanwhile back in the tunnel, it occurs to me that (1) You might think you are going faster, because of the subjective effect of the walls and roof being much closer to the steerer, and (2) you might actually be going faster because there is so little collected detritus on the bottom (no falling leaves, as someone else has said) and most boats are happier in deeper water.

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Forgive my ignorance, but can't canines be persuaded to have "just in case wees", like children?

 

Meanwhile back in the tunnel, it occurs to me that (1) You might think you are going faster, because of the subjective effect of the walls and roof being much closer to the steerer, and (2) you might actually be going faster because there is so little collected detritus on the bottom (no falling leaves, as someone else has said) and most boats are happier in deeper water.

 

Up to a couple of years ago we had to plan our cruising schedule around our old lurcher who had become very incontinent - it was easy doing lock flights but you soon discover there are extended sections of the canal network where it's nigh on impossible to get into the side at least to lift an old dog onto the towpath.

 

 

Thinking on, IIRC even Tom Rolt cursed his boats lack of speed on certain parts of the network where it's so tedious you just want to get it over with. I'm thinking of those arrow straight parts of the Shroppie where you see a boat in the distance but don't meet it for half an hour.

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I think everybody should be allowed to go at whatever speed they want as long as that doesn't mean that other boaters suffer. If there's a very slow boat in front of me and I catch him up, I hope he will let me pass when safe so we can both proceed at our preferred speed. If he doesn't then he is imposing his regime on me and that isn't fair. In my view, not enough boats do move over for those who may be in a hurry for whatever reason.

I think I have only come across that situation about half a dozen times, maybe a few more.

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I'd have taken him at his word. Opened it right up for a bit,hope he likes exhaust smoke. My gardner can lay on a good smoke screen if you wind it right up.

He`d soon back off. Failing that Chuck a length of old rope off the back, that'll slow him down a bit as it gets ravelled up in his prop.

Only joking.. tunnels aren't the safest place, so don't try this at home.

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Wouldn't a boat close behind be a drag on the one ahead? In any channel of limited depth or width, you can see the water ahead being pulled being pulled towards you (bending of reeds, etc.)so a boat close behind will slow down the one in front. No?

As I understand it that's what happens. The boat behind is pulling the water too.

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I can think of a number of reasons to be in a hurry.

 

One of your dogs is desperate for a leak and there's nowhere to get into the side.

 

You're on that evil smelling section of the North Oxford

 

You're trying to make the 3pm cut off for Harecastle tunnel and the boat in front has held you up several times once to salvage a plastic bag from the canal FFS, then "ooh I must take a photograph of that" without pulling into the side.

 

It's getting dark and you know there's only one decent mooring spot left at Fradley.

 

Crikey that couple we just shared a lock with were a bit weird weren't they...

 

You're navigating the Wigan flight.

 

You're in Blackburn, Nuneaton, Ashton (insert your own selection here)

 

You're on the Bridgewater expressway, yesssss....

Cor blimey, good luck going fast through Nuneaton.

I think I have only come across that situation about half a dozen times, maybe a few more.

I think it is quite hard sometimes for people to judge where is a good safe place to let someone pass, so instead pretend not to notice that they're there.

It's worse in a way when someone tries to let you by somewhere that's not really suitable.

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We were in a similar position in October in Chirk tunnel, but we were the boat behind. We did end up close to the Viking Afloat boat in front as it came close to a complete stop, but with its engine at about 3000 revs! The noise and the smoke were unbelievable. We stopped and tried to shout some advice about a burst of reverse to dislodge leaves, but they couldn't see or hear us! It was at that point one of their crew decided legging the boat through was the best idea! So with their engine on full tilt and a man on the roof of the boat, we dropped back so we could breath a bit better, and followed them at 0.1mph!

 

They pulled over when they got out of the tunnel. They looked exhausted!

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I'm happy to be corrected by those it may have happened to, but I wouldn't really expect leaf fall to be a major problem in Braunston tunnel.

 

I accept there is some very slow flow, and some will get drawn in, but I wouldn't expect amounts large enough to produce adverse effects all the way through.

 

Having gone through that tunnel a couple of weeks ago, my experience was a bit similar to the OP's (not being followed & harassed by pratt in a hurry, but losing speed). After a while I thought of dropping into neutral & / or giving a burst of reverse, which seemed to improve things for a few minutes each time. So I think that leaves, no doubt being drawn into the tunnel by boats going through it, probably are at least partially a cause of the problem.

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Leaves aren't normally an issue on the GU but that would be my explanation too.

 

We spent ten days on the Staffs & Worcs a week or two back and I reckon I was in reverse as much as forward. The locks were impossible, we had to haul the boat through most of them. But it was worth it for the experience of being the only boat on Tixall wide on a flat calm morning.

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Leaves aren't normally an issue on the GU but that would be my explanation too.

 

Try Tring summit in leaf fall season, and you might say otherwise!

 

However I'm rather surprised if it were an issue all the way through one of the long tunnels - it's possible though I'll admit.

 

(But if it were affecting everybody the boat behind might have struggled to catch up as fast as is described - you might imagine he would also achieve little by winding the power on......)

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