Passing above tickover

[Emerald Fox]

Window Tappers - Please tap your finger on the window in rythm to the beat of our engine as we go past on tickover.

 

Do ducks go past on 'kickover' ?

[bastion]

Surely it all depends on the design of the individual boat, yesterday evening 2 boats came past me on the south Oxford, one at a fast rate hardly move my boat and one that seemed to take forever to go past moved my boat quite alarmingly and pulled my pins out partially.

[by'eck]

I suspect slowing down to pass has only become the 'rule' since the 1980's The Guys and Gals who drove their boats for a living would have a huge belly laugh at the thought.

 

Yes I do slow down as I respect peoples wishes, but unless moored on pins it should not matter if you are correctly moored.

 

It seems you fail to appreciate the need to slow down when the conditions of canal width and depth demand it. There can be no firm rules applied to this, simply a matter of adapting to conditions. If in doubt slow down of course, but when the bottom of the canal is revealed at the edges by your wake, it can be safely assumed you are travelling too fast for its depth.

 

The guys and gals who drove their boats for a living wouldn't have made much of one if they were constantly having to refloat their boats after being pushed aground whilst passing others. I suspect this didn't happen of course despite their fully laiden draughts simply because the canals had to be better maintained, with regard to depths at least.

 

Totally nothing to do with rules but everything to do with common sense in avoiding what can and does happen. Many is the time when a boats crew have stared back at mine temporarily aground, with a mixture of amazement and embarrasment on their faces, after not realising the consequences of the significant bow wave their excess speed was creating.

Edited July 24, 2015 by by'eck

[by'eck]

Surely it all depends on the design of the individual boat, yesterday evening 2 boats came past me on the south Oxford, one at a fast rate hardly move my boat and one that seemed to take forever to go past moved my boat quite alarmingly and pulled my pins out partially.

 

Depends on different boats yes, but mainly because of their varying draughts. Efficient swims will help, but being displacement hulls its mainly down to the amount of water they push out of the way when moving at any given speed, assuming we are talking about narrowboats.

[blackrose]

I think some canal boaters are bordering on being hyper-sensitive about the movements of other boats. One wonders whether they'd be happier back on land.

 

I've been mooring on rivers for the last 5 years where the "slow down past moored boats" culture is virtually non-existent. I realise that's partly due to the wider, deeper water of the river, but when a 90 x 15ft passenger boat passes at 5knots you certainly feel it.

 

I think quite a few canal boaters would get a bit of a shock with the speed boats pass if they moored on some rivers.

Edited July 25, 2015 by blackrose

[gazza]

I find mooring on pins is usually better than Haphazardly placed rings and bollards.

Use a spring

[Scholar Gypsy]

I think some canal boaters are bordering on being hyper-sensitive about the movements of other boats. One wonders whether they'd be happier back on land.

 

I've been mooring on rivers for the last 5 years where the "slow down past moored boats" culture is virtually non-existent. I realise that's partly due to the wider, deeper water of the river, but when a 90 x 15ft passenger boat passes at 5knots you certainly feel it.

 

I think quite a few canal boaters would get a bit of a shock with the speed boats pass if they moored on some rivers.

 

I would also add that I regularly use biggish squashy fenders when mooring up, on rivers and canals. I find that this means that any movement that does occur (even after using springs etc etc) creates much less grinding and bumping.

 

 

PS you do need to remember to lift your fenders when cruising. (source)

 

Edited July 25, 2015 by Scholar Gypsy

[Dave_P]

I think some canal boaters are bordering on being hyper-sensitive about the movements of other boats. One wonders whether they'd be happier back on land.

 

I've been mooring on rivers for the last 5 years where the "slow down past moored boats" culture is virtually non-existent. I realise that's partly due to the wider, deeper water of the river, but when a 90 x 15ft passenger boat passes at 5knots you certainly feel it.

 

I think quite a few canal boaters would get a bit of a shock with the speed boats pass if they moored on some rivers.

On rivers the movement is generally caused by the passing boat's wake. On narrow/shallow canal it's caused by the surge from the hull displacement. Entirely different things. I never have much problem mooring on rivers, but tied on a shallow edge of a narrow canal, the 'pull' can be huge.

 

Factors affecting this are many: the size and profile of your boat, the size and profile of their boat, the canal width, the canal depth, the way you're tied up, the height of the bank, the speed of the passing boat.

 

The solution is simple: if you're passing boats and they're being dragged around, or pulled sideways and down, slow down.

 

I often moor away from other boats on my own. It's shocking how many boats don't slow at all. They're clearly assuming there's nobody in. Then I appear at the window and they quickly knock the revs back slightly, out of embarrassment, even though they've nearly passed me.

[by'eck]

I think some canal boaters are bordering on being hyper-sensitive about the movements of other boats. One wonders whether they'd be happier back on land.

 

I've been mooring on rivers for the last 5 years where the "slow down past moored boats" culture is virtually non-existent. I realise that's partly due to the wider, deeper water of the river, but when a 90 x 15ft passenger boat passes at 5knots you certainly feel it.

 

I think quite a few canal boaters would get a bit of a shock with the speed boats pass if they moored on some rivers.

 

You raise some relevant points. Yes on deeper, wider rivers people worry less simply because the effect of a moving boats displacement of water is diluted to a very large degree. As you say even on such rivers, there comes a point when a passing vessel is large enough to cause issues to those moored.

 

At the other end of the scale though are those with shallow draught boats who choose to moor on the banks of narrow, shallow canals where they can expect virtually every passing boat to cause movement of theirs to a greater or lesser degree. I certainly cannot agree that such people are being over sensitive about such, though unwise maybe, since its easy to see in advance that mooring in the remote shallow places they do, secured with mooring pins, they will have problems with many passing boats.

 

Having said that there are many poorly maintained visitor moorings that offer only modest depths at the bank. At least mooring rings or bollards provided help to reduce the effects of inevitable buffeting by passing boats though.

[blackrose]

But boats are supposed to move - isn't that the whole point? If people want a static mooring then perhaps they should think about a caravan?

 

 

PS you do need to remember to lift your fenders when cruising.

 

I never remember and have never had a problem. When I enter a river lock single-handed with other boats waiting inside I'm glad to know my fenders are down.

[gazza]

But boats are supposed to move - isn't that the whole point? If people want a static mooring then perhaps they should think about a caravan?

 

 

I never remember and have never had a problem. When I enter a river lock single-handed with other boats waiting inside I'm glad to know my fenders are down.

I can't be arsed with yo yoing the fenders up and down, nine times out of ten I'm working the boat thru a lock or mooring up on my own. The only access to the bow is down the nice wide gunwale - kicking the fenders in every time I want to get there seems daft just to please those with a daft fixation on a wafi habit

[Nightwatch]

As mentioned often, I always slow down when passing moored boats.

 

However,the other day we had a potential embarrassing situation. Cruising along nicely, slowed before we got to the moored boat we were about to pass, and the following wake waves were overtaking us, here we go I thought, nope. It was okay. Useless comment I know, but thought I'd say it anyway.

[Scholar Gypsy]

I can't be arsed with yo yoing the fenders up and down, nine times out of ten I'm working the boat thru a lock or mooring up on my own. The only access to the bow is down the nice wide gunwale - kicking the fenders in every time I want to get there seems daft just to please those with a daft fixation on a wafi habit

 

Thanks - not an acronym I'd heard before but acronymfinder.com came to the rescue. I think you mean #3?

 

I rather agree with you to be honest (but not on a narrow canal).

[gazza]

 

Thanks - not an acronym I'd heard before but acronymfinder.com came to the rescue. I think you mean #3?

 

I rather agree with you to be honest (but not on a narrow canal).

That's the one, slightly different word beginning with F though many to be found on expensively restored wooden broads sailing boats barking orders at all and sundry! Edited July 25, 2015 by gazza

[MoominPapa]

To get back to the original point, I have noticed more probs with speeding boats between Preston Brook and Middlewich which I put down to folk coming off the Bridgewater and not adjusting to the conditions. You see the same thing on canals that join river navigations.

Another possible explanation along there is that there are two tunnels with timed entrance (Preston Brook and Barnton, IRC) so people may be pushing it in an attempt not to have to wait at the tunnel for 50 minutes.

 

MP.

[WhiteSuit]

While balanced on the bow of my boat touching up paint last week I hade this moron reverse past me and give my hull a hefty clonk. It was quite alright though this wayward helmsman had his boat festooned with pass at tickover signs. Obviously needs one to tell him not to be a numb nutz.

[BruceinSanity]

Another possible explanation along there is that there are two tunnels with timed entrance (Preston Brook and Barnton, IRC) so people may be pushing it in an attempt not to have to wait at the tunnel for 50 minutes.

 

MP.

You may well be right, (it's Saltersford that's the other timed entrance).

[Emerald Fox]

I do wish lorries would pass me on the M1 at tickover as I may be having a snooze or doing a very important text message.

 

I'm juicing up our tickover this afternoon to 9000 RPM.

[Theo]

 

Small point here - it isn't really the speed of the boat that pulls water out from under moored boats, its your prop, pushing it all backwards. Going past at 2+mph but having been in neutral for 50 yards won't usually drag out someone's water from under them. Even worse would be a really slow, heavy boat at high rpm, struggling to drag his big *rse through the mud - but if he didn't do that he'd probably grind to a halt.

 

Notice how quickly the water is moving backwards on both shores to your sides. The quicker it moves backwards, the shallower it is and the more difference it will make to the boat tied up just ahead of you.

 

I doesn't happen at Tixall, for example, which is why one poster said it didn't affect his moored boat at all. The more water there is available, the less it affects the grumpy.

 

Blither

 

I couldn't disagree more. It is the speed of the boat over the ground which gives rise to the "draw". If the cross sectional area of the canal is small compared with that of the boat there is a large flow of water in the direction opposite to that in which the boat is travelling.

 

N

[Scholar Gypsy]

 

I couldn't disagree more. It is the speed of the boat over the ground which gives rise to the "draw". If the cross sectional area of the canal is small compared with that of the boat there is a large flow of water in the direction opposite to that in which the boat is travelling.

 

N

 

Indeed so. The average speed of the water, moving backwards over the ground as a boat goes past forwards, is equal to the speed of the boat divided by:

 

(cross section of boat)/(cross section of canal) - 1.

 

This speed will be negligible on wide rivers (where wash ie surface waves is more of a factor) but will be significant on narrow & shallow canals.

 

This result follows from the fact that as the boat moves forward, water moves from in front of it (to create a hole that the hull then moves into, if you like) to behind the boat (to fill the hole that it vacates).

 

The actual pattern of flow will be much more complex of course - this just gives the average speed across the entire cross section of the canal. The action of the prop will have an impact - but the water it moves from in front of the boat to behind is just part of the overall flow described above,

[Scholar Gypsy]

I wouldn't like to cruise past this boat (photo from https://twitter.com/Fo_RegentsCanal). Still the alternative is driving mooring pins into the 400 KV cables in the towpath.

 

 

 

[Loafer]

 

Indeed so. The average speed of the water, moving backwards over the ground as a boat goes past forwards, is equal to the speed of the boat divided by:

 

(cross section of boat)/(cross section of canal) - 1.

 

This speed will be negligible on wide rivers (where wash ie surface waves is more of a factor) but will be significant on narrow & shallow canals.

 

This result follows from the fact that as the boat moves forward, water moves from in front of it (to create a hole that the hull then moves into, if you like) to behind the boat (to fill the hole that it vacates).

 

The actual pattern of flow will be much more complex of course - this just gives the average speed across the entire cross section of the canal. The action of the prop will have an impact - but the water it moves from in front of the boat to behind is just part of the overall flow described above,

 

I've sat and watched it for ages and done many trials, both in and out of gear. What I said is true for my deep-draft boat. Help yourselves.

 

I'm not bothered by it and I don't cause moorers any problems as a result.

 

You're also wrong about speed over the ground. It's speed through the water that counts, plus prop wash. The prop wash factor increases massively with shallowing water.

 

If you were in neutral for ages, going downstream helplessly with a 3-mph flow, in a fast river, your 3 mph over the ground wouldn't affect anyone at all, moored next to your passing. Not that you'd be able to steer, so you'd affect them if you hit them - but that isn't your point.

Edited July 26, 2015 by Loafer

[Loafer]

Further to my last, if I was dragging through the mud next to a moored boat, hardly moving at all but pushing a lot of water backwards at high rpm, there'd hardly be ANY water left under the moored boat. AND the one ahead of that. My speed over the ground would be almost zero. My speed through the water would be arguable - probably defined by the speed of the water passing along the sides of my almost-aground boat.

 

I'm tired now!

Edited July 26, 2015 by Loafer

[Scholar Gypsy]

Further to my last, if I was dragging through the mud next to a moored boat, hardly moving at all but pushing a lot of water backwards at high rpm, there'd hardly be ANY water left under the moored boat. AND the one ahead of that. My speed over the ground would be almost zero. My speed through the water would be arguable - probably defined by the speed of the water passing along the sides of my almost-aground boat.

 

I'm tired now!

 

Um, I think you are trying to change the laws of physics (conservation of mass), but never mind!

 

The earlier result (for average flow) assumes one is on a canal (with no ambient current, and a reasonably constant cross section) not a river. If you are not moving over the ground then the net flow past the boat is (or will stabilise at) nil - ie all the water that your prop is pushing backwards is offset by flows (weaker, as less concentrated) in the opposite direction. Of course, as you say and especially in shallow water, the moored boats would certainly notice your presence if you rev the engine.

[Loafer]

 

Um, I think you are trying to change the laws of physics (conservation of mass), but never mind!

 

The earlier result (for average flow) assumes one is on a canal (with no ambient current, and a reasonably constant cross section) not a river. If you are not moving over the ground then the net flow past the boat is (or will stabilise at) nil - ie all the water that your prop is pushing backwards is offset by flows (weaker, as less concentrated) in the opposite direction. Of course, as you say and especially in shallow water, the moored boats would certainly notice your presence if you rev the engine.

 

 

The highlighted red bit is not true either. If you are sitting at 1/4 throttle against a flow, holding a static position over the ground, then your speed through the water is the same as the opposing current speed (as long as you are not fixed to the ground in some way). You are consuming energy to get through that moving water, even though you are not gaining any 'ground'.

 

In ALL cases that I have studied, which I automatically do now almost all the time, (I use it to judge if I'm likely to be able to moor there) my speed through the water isn't the main thing that makes moored boats get dragged off their pins, or lean over. It's much more dependant on my power setting at the time, i.e. how much of water ahead of me is rushing past me, to fill in the gap caused by my prop 'suction'.

 

The 'net flow past my boat', if I'm static relative to the earth, equals the 'current' current (sic). If I'm floating, that is.

 

I'm happy to be convinced otherwise by the more knowledgeable, but in this case I still believe in what I said, because I learned it from not only knowledgeable people outside this forum, but also from years of detailed observation (I'm very sad like that!)

 

I can't change the laws of physics unless I discover a new law. Newton did most of that, already, along with that Archimedes mate of his.

 

Please continue - I'll be happy to re-heddicate myself if it becomes necessary. If I stop responding, it'll be because I've fallen over.