entering a lock with a strong bywash

[pophops]

I'm sure you will recognise the situation. You get the bow nicely lined up for the lock entrance when the stream pushes you off line. You steer towards the steam to bring the bow back on line with the entrance but this steers the stern the opposite way and the bywash pushes the back end even further over. The result is another chunk out of the brickwork and another complaint from the crew with instructions to "be careful".

What is the best way to approach a lock with a strong bywash stream?

[cheshire~rose]

With as much speed as your confidence allows - this confidence will grow with more time. Of course if you get it wrong it will mean a bigger impact with the brickwork but the increased speed means the steering is more effective against the flow of the bywash.

[Guest]

I'm sure you will recognise the situation. You get the bow nicely lined up for the lock entrance when the stream pushes you off line. You steer towards the steam to bring the bow back on line with the entrance but this steers the stern the opposite way and the bywash pushes the back end even further over. The result is another chunk out of the brickwork and another complaint from the crew with instructions to "be careful".

What is the best way to approach a lock with a strong bywash stream?

 

Approach from the side it is coming from and it lines you up as you approach the mouth of the lock.

 

Problem is if you overestimate how much it will push you, the boat hit's the other side.....and you get the same effect...

[johnmck]

One of the times a bow thruster comes in very handy.

 

 

Takes coat and exits swiftly.

[Tam & Di]

With as much speed as your confidence allows - this confidence will grow with more time. Of course if you get it wrong it will mean a bigger impact with the brickwork but the increased speed means the steering is more effective against the flow of the bywash.

This is 100% correct, and applies to many other manoeuvres as well. I often get people who say "I drift into locks so if I hit anything it won't cause a lot of damage". My reply is that there is really no "if" about it, as you only have control of your boat if you have enough power on to give you positive steering.

[dor]

I've had plenty of experience of this on the Llangollen! Be positive and keep your speed up. You have to judge the strength of the by wash, so the next bit requires a bit of experience. With towpath on the left and wash coming from the right, head straight towards the lock but about four foot to the right. As the bows enter the wash, steer into it but let it push you towards the lock. Then you will ned to push the tiller over the other way to hold the stern against the current. If no one is watching you will glide gracefully into the lock without touching the sides. If anyone is watching of course...

[Paul C]

As above, really. In theory you can maintain a straight (lined up with the lock) direction, but displaced perhaps half a boat width to allow for the bywash. The theory being that when the bywash hits the bow, it pushes the boat out of line, then once this is clear and it hits the stern, it will push it back in line. But in practice you tend to continue to 'steer' to guide the nose in accurately, then the back in, to compensate for the weir wash.

 

With regards putting power on - the more engine power you use, the less you need to compensate and also a by-product is the better (quicker to respond) is the boat's steering. So, more power rather than less, is the way to go.

 

We are quite fortunate in having a boat short enough (45 foot) that we can get past the bywash before entering the lock. On the llangollen ones, they're shallow enough to be able to get past the weir, then stop the boat in the lock mouth, and get on/off the boat here. But you need to be able to judge it correctly with the right amount of speed and 'offset' to get the boat past the weir and accurately near the lock, with not-too-much speed so you can stop without hitting the gates (or brickwork). It is possible but needs a reasonably good judgement.

[RLWP]

There is something counter-intuitive to do once the boat has hit the mouth of the lock too. Once it has all gone pear-shaped* and the bow has bounced off the wall, rather than try to steer the bow away from the wall, put the tiller across to try to hold the bow on. This will prevent the boat getting across the mouth of the lock and jamming (cross-winding). Tawny has been cross-winded many times, which is why the bathroom door won't bolt at the moment (Bazza)

 

Richard

 

*which is good, if you are a pear

[Barry]

There is something counter-intuitive to do once the boat has hit the mouth of the lock too. Once it has all gone pear-shaped* and the bow has bounced off the wall, rather than try to steer the bow away from the wall, put the tiller across to try to hold the bow on. This will prevent the boat getting across the mouth of the lock and jamming (cross-winding). Tawny has been cross-winded many times, which is why the bathroom door won't bolt at the moment (Bazza)

 

Richard

 

*which is good, if you are a pear

 

 

I know...It was me. I didn't know what was happening or why and I still feel rotten about it

 

 

Actually what I need is for for someone to sit down with me with a pen and a piece of paper and draw what happened and what I should have done because with the best will in the world the word pictures being painted above don't work for me

Edited April 15, 2013 by Bazza2

[RLWP]

 

What happened is Tawny Owl realised you were not fully aware of what was happening and decided to catch you out

 

If you check the hull, she's had many people with that trick over the years, us included!

 

And it may make you feel rotten, I had forgotten exactly who and how - in fact I vaguely recollected it was me.

 

Richard

[Doug_]

An old hand told me to open a paddle slightly to let the water through the lock instead of the by wash. Never tried it because I'm usually on the boat and she just watches me struggle. Hey Ho

[pophops]

Thanks for the replies. The concensus seems to be full speed ahead and aim at the lock wall! I'll give it a go just as soon as soon as I've had the brakes re-lined.

[furnessvale]

An old hand told me to open a paddle slightly to let the water through the lock instead of the by wash. Never tried it because I'm usually on the boat and she just watches me struggle. Hey Ho

With LLangollen or Shroppie bywashes that wouldn't divert enough water to have the desired effect. All you would do is wash detritus from the lock onto the lower cill possibly stopping a good seal when you close the bottom gates.

 

George ex nb Alton retired

[Keeping Up]

With LLangollen or Shroppie bywashes that wouldn't divert enough water to have the desired effect. All you would do is wash detritus from the lock onto the lower cill possibly stopping a good seal when you close the bottom gates.

 

George ex nb Alton retired

 

I did hear of the technique being used to good effect on the lock at Audlem above the Shroppie Fly, to reduce the flow from the outfall and also bring the boat to a halt in the lock. The person who told me claimed to have watched the working boats do it "in the old days" but of course they may have just been spinning a line.

[NB Alnwick]

An old hand told me to open a paddle slightly to let the water through the lock instead of the by wash. Never tried it because I'm usually on the boat and she just watches me struggle. Hey Ho

I have to admit that I have occasionally done this when going down hill single handed. After opening the top gate, partially opening one of the bottom gate paddles helps to draw the boat into the lock and this often works very well - it also makes it easier to close the top gate when the boat is in the lock

 

Of course, it all depends on the lock and like many other things in life, there is no substitute for experience and knowledge of the route . . .

 

Entering the lock with speed and power to provide good steering isn't an option when you are single handed and, most likely, on the bank hauling the boat into the lock with the centre line.

[furnessvale]

I did hear of the technique being used to good effect on the lock at Audlem above the Shroppie Fly, to reduce the flow from the outfall and also bring the boat to a halt in the lock. The person who told me claimed to have watched the working boats do it "in the old days" but of course they may have just been spinning a line.

The difference being that this technique was used to "brake" the incoming boat and the paddle(s) were only lifted after the boat had entered the lock. Indeed, with a loaded boat it was not considered necessary by some as the piston effect of the boat in the lock would slow the boat followed by quickly closing the back gates.

 

I cannot see that, where a bywash is causing trouble, sufficient water could be diverted through a lock by lifting paddles as to stop that trouble, without causing problems for the boat entering and/or debris on the bottom cill.

 

George ex nb Alton retired

[nicknorman]

If its any consolation to the OP seeing others do this effortlessly, a lot can depend on how well you boat steers. Ours has a really big rudder and therefore great steering even at low revs (in fact its not bad even in neutral) but we see so many boats, especially some hire boats, that seem to be very under-ruddered. The steerer is applying masses of rudder with reasonable power on, but the boat just goes pretty much straight ahead with lots of tiny-prop froth coming straight out of the back.

 

Its also worth bearing in mind that more than about 60 degrees of rudder is likely to be too much and it will become less effective. I watched an long Anglo Welsh boat trying to wind the other day - the rudder went beyond 90 degrees and they wondered why it wasnt really steering!

 

So if you are finding it difficult, it might be your boat and not you!

 

Edited to say its not only bywashes that cause unpredictable problems - the Knowle locks on the upper Grand Union are terrible for being perfectly lined up for 1 gate (or with 1 boat already in) and then the boat suddenly starts going sideways big-time. Someone told me that its due to currents circulating in the pounds due to the large paddles, but I think there are mud-monsters lurking, who like nothing better than to scratch their backs against the hulls of passing nbs, thus pushing them sideways.

Edited April 17, 2013 by nicknorman

[Keeping Up]

The difference being that this technique was used to "brake" the incoming boat and the paddle(s) were only lifted after the boat had entered the lock. Indeed, with a loaded boat it was not considered necessary by some as the piston effect of the boat in the lock would slow the boat followed by quickly closing the back gates.

 

I cannot see that, where a bywash is causing trouble, sufficient water could be diverted through a lock by lifting paddles as to stop that trouble, without causing problems for the boat entering and/or debris on the bottom cill.

 

George ex nb Alton retired

 

No, I was specifically told that the prime purpose on this particular lock - which has an exceptionally fierce outfall under the bridge below the lock - was to reduce the flow of water through the bywash, and that the well-known use of this method to act as a brake was just a bonus in this one particular case (indeed I was told that the further refinement was to drop the paddle once the bows of the boat were safely in the lock, to allow the boat to proceed unhindered, and then raise it again a brief period later to act as a brake, but only if the person doing so could be bothered!).

 

Certainly I can confirm from observation that the flow through the bywash on that lock is temporarily reduced considerably when the top paddle is first opened.

[furnessvale]

No, I was specifically told that the prime purpose on this particular lock - which has an exceptionally fierce outfall under the bridge below the lock - was to reduce the flow of water through the bywash, and that the well-known use of this method to act as a brake was just a bonus in this one particular case (indeed I was told that the further refinement was to drop the paddle once the bows of the boat were safely in the lock, to allow the boat to proceed unhindered, and then raise it again a brief period later to act as a brake, but only if the person doing so could be bothered!).

 

Certainly I can confirm from observation that the flow through the bywash on that lock is temporarily reduced considerably when the top paddle is first opened.

Interesting. I know the lock in question and went through it last week. The bywash was running strongly but I allowed for it and slid in sweet as a nut.

 

A couple of thoughts come to mind. Would working boatmen, far more experienced than me, bother with this technique rather than making allowance like I did?

 

Secondly, perhaps my memory is playing tricks but I seem to recall that the fierce bywash problem only started when additional water was sent down the Shroppie from Wolverhampton level coal mines and that this started after the end of commercial carrying.

 

Hopefully someone will be along shortly with chapter and verse?

 

George ex nb Alton retired

Edited April 17, 2013 by furnessvale

[onionbargee]

steer into the wash, and let it push you back into line with the lock.

[nigel carton]

What he said above, Woolhampton on the K & A is a good one to practice on, and good fun!!

[Radiomariner]

Little bit of additional advice. If there is a boat coming out of the lock, hang well back until it is clear of the side wash, you can not know how experienced the other boater is. How do I know this? Nasty dent on my port bow quarter, LLangollen

 

Edited to add: My daughter was steering and I was on the towpath. I really wish I had not shouted to him to "go faster" just before he rammed Peppers Paw!

Edited April 18, 2013 by Radiomariner