Narrow boat stuck across Chertsey bridge

[ditchcrawler]

Hmmm, that went wrong didn't it. I recall a navy frigate(?) doing the same thing a few years ago on the tidal Thames, mind you, as someone hugely skilled and highly experienced that sort of thing would never happen to me. Yes I know there was that time at Amiens but I meant to moor there and all that shouting was just me practising French.

I have seen a coaster across the Haven Bridge in Gt Yarmouth

The simple answer is that the boat should NOT have been navigating at all while the River is on Red boards.

Reds cover a wide range of current speeds and at the time the flows were well towards the maximum.

 

Most NBs on the Thames do not have enough power to cope with strong flows.

Folks venture out without having a clue and more importantly make no effort to find out what the implications of their actions might be.

Looking at the video the water was a bit lively, I don't think I would have been there.

[WJM]

Clearly Darwin is alive and well and travelling on that narrowboat - Red Boards, an emergency situation with the Fire Brigade in attendance - and a man is out on the gunnels pushing WITHOUT A LIFEJACKET!!!! Some people shouldn't be allowed out!

[blackrose]

 

Can you explain why rounding up to stem a current or tide, and the accompanying necessity of being 'beam on to the current' for a few moments whilst doing so, causes quite so much anxiety among so many of today's pleasure boaters?

I think that I've worked out some of the reasons why, but it would be good to get them confirmed by someone who clearly has a problem with it.

 

I didn't say I necessarily had a problem with it - can you explain exactly where you think I clearly said I had a problem with it? You certainly won't get your "reasons" confirmed by me. Once again you're making assumptions and typically misreading my post - perhaps deliberately.

 

Whether a turn into the current becomes a problem really depends on the waterway, the situation, the power available and the person handling the boat. I've seen a 70ft narrowboat trying to turn into a current and it stayed beam on for a lot longer than a few moments - in fact it didn't end up completing the turn at all. However, I certainly don't have a problem making the manoeuvre in the right situation.

Edited March 15, 2016 by blackrose

[blackrose]

duplicate post

Edited March 15, 2016 by blackrose

[Bee]

Whilst I agree about an earlier post about going backwards downstream under a bridge, with forward power on, I would just LOVE to stand on that bridge and watch the 'average narrowboater' try that!

I've tried that in a strong flow under Osney Bridge in Oxford, I had the wheelhouse down but its really tight at the best of times and the river was well up and I was not sure if the mast tabernacle would have to be removed. The boat is a 10 metre replica Dutch tug and it took several attempts to back down. In the end the tabernacle had to come off so we pushed off back up the river, removed it and then turned and shot back under Osney bridge going like a train with about half an inch clearance kneeling on the wheelhouse floor knowing that we could make it. Exciting, risky and going backwards whilst in forward is actually harder than it looks, there is a bit of a side current upstream of Osney but the flow of water constantly catches the bow and pushes it off.

[Tony Dunkley]

 

I didn't say I necessarily had a problem with it - can you explain exactly where you think I clearly said I had a problem with it? You certainly won't get your "reasons" confirmed by me. Once again you're making assumptions and typically misreading my post - perhaps deliberately.

 

Whether a turn into the current becomes a problem really depends on the waterway, the situation, the power available and the person handling the boat. I've seen a 70ft narrowboat trying to turn into a current and it stayed beam on for a lot longer than a few moments - in fact it didn't end up completing the turn at all. However, I certainly don't have a problem making the manoeuvre in the right situation.

 

What you have said in your second paragraph does in fact confirm exactly what I thought.

 

You start by saying that whether or not 'a turn into the current becomes a problem really depends on the waterway', and this, with the exception of the reference to 'the person handling the boat', is the only part of what you say that gets anywhere near to being correct or factual.

 

The waterway itself can only be a problem if the boat is too long to swing in the available width, otherwise it has no effect whatsoever on rounding up.

 

As for what you call the 'situation', the only 'situation' that will have any effect is if, through either bad judgement or inexperience, you've underestimated the tide or current, left it all too late and started a manouevre that you won't have time to finish before you crash into something.

 

That takes us on to your next mistaken belief, that the 'power available' is influential on vessel's ability to round up and stem a tide or current. This is simply not so, as a little thought on the matter will show. Any vessel of any sort will invariably turn shortest round whilst carrying minimum way, and power is something you don't need to achieve that.

 

Finally that brings us to the last of your 'problems', namely 'the person handling the boat', . . . . and you've got that right !

 

In your preoccupation with your wrongly perceived effects of tide or current, your appear to have forgotten completely to mention or take into account the potential effects, helpful or otherwise, of wind strength and direction relative to tide or current.

[Loafer]

 

What you have said in your second paragraph does in fact confirm exactly what I thought.

 

You start by saying that whether or not 'a turn into the current becomes a problem really depends on the waterway', and this, with the exception of the reference to 'the person handling the boat', is the only part of what you say that gets anywhere near to being correct or factual.

 

The waterway itself can only be a problem if the boat is too long to swing in the available width, otherwise it has no effect whatsoever on rounding up.

 

As for what you call the 'situation', the only 'situation' that will have any effect is if, through either bad judgement or inexperience, you've underestimated the tide or current, left it all too late and started a manouevre that you won't have time to finish before you crash into something.

 

That takes us on to your next mistaken belief, that the 'power available' is influential on vessel's ability to round up and stem a tide or current. This is simply not so, as a little thought on the matter will show. Any vessel of any sort will invariably turn shortest round whilst carrying minimum way, and power is something you don't need to achieve that.

 

Finally that brings us to the last of your 'problems', namely 'the person handling the boat', . . . . and you've got that right !

 

In your preoccupation with your wrongly perceived effects of tide or current, your appear to have forgotten completely to mention or take into account the potential effects, helpful or otherwise, of wind strength and direction relative to tide or current.

 

Tony, is it true to say that rounding up in a strong current is dynamically the same as turning through 180deg on a lake, except that some large stone structure is coming towards you at the speed of the current?

 

I'm guessing that some local turbulence might have an effect here and there, but that is just as likely to help you round, as hinder you.

 

(All assuming the same speed through the water, or 'boat speed', not ground speed)

[MoominPapa]

 

Tony, is it true to say that rounding up in a strong current is dynamically the same as turning through 180deg on a lake, except that some large stone structure is coming towards you at the speed of the current?

 

That's not quite true in a channel, as the current will be greater at the centre than close to the banks. You can therefore help yourself by putting the end of the boat that you want to be downstream in the middle, and the end that you want to be upstream at the side. In extremis, you could even jam that end into the bank to stop it moving at all whilst the current moves the other end. That tends to work better with the bow than the stern.

 

 

MP

Edited March 15, 2016 by MoominPapa

[Loafer]

 

That's not quite true in a channel, as the current will be greater at the centre than close to the banks. You can therefore help yourself by putting the end of the boat that you want to be downstream in the middle, and the end that you want to be upstream at the side. In extremis, you could even jam that end into the bank to stop it moving at all whilst the current moves the other end. That tends to work better with the bow than the stern.

 

 

MP

 

For sure.

[Tony Dunkley]

 

Tony, is it true to say that rounding up in a strong current is dynamically the same as turning through 180deg on a lake, except that some large stone structure is coming towards you at the speed of the current?

 

I'm guessing that some local turbulence might have an effect here and there, but that is just as likely to help you round, as hinder you.

 

(All assuming the same speed through the water, or 'boat speed', not ground speed)

 

Yes, that sums it all up very neatly. The movement of a boat relative to the water surrounding it is no different whether it's in a fast flowing river or completely still water like a lake or a canal.

 

The tendency that narrowboats have to roll, or lean outwards, when rounding up in a fast flowing river is due solely to them achieving a high rate of turn at a much higher speed through the water than they would ever achieve whilst making the same rate of turn on a sharp bend and at lower speed in a canal. Relatively long, narrow ships, such as destroyers, do the same thing and can list or 'lean' outwards very noticeably in high speed turns. I can quite understand why people more used to handling boats on still, narrow waters like canals find this a bit disconcerting, but when it does happen then it's a sure indication that the boat speed through the water is much too fast for the highest rate of turn and the tightest possible radius of turn.

Reducing a boat's speed down to the minimum needed for steerage way prior rounding up is of significant help in more than one way. Not only will rounding up take less river width to complete, but it also gives you the opportunity to make a better assessment of current/tide speed and wind direction/speed and the likely effects of all of them on what you're about to do.

 

As you say, turbulence or areas of slacker water, can either hinder or help, and their presence and location is something that must always be taken in to account when planning or executing any kind of manoeuvre in a strong current or tide.

When rounding up to stem the tide or current it's essential to turn into the slacker water, even if that means turning away from a side lock or channel that you intend to enter, and the reverse applies when stemming a current/tide and turning to run with it, when you must get into the slackest water before then turning out of it.

Edited March 15, 2016 by Tony Dunkley

[Loafer]

Indeed. The overriding tendency with newbies, on a river though, is to throttle back to combat their scary downstream groundspeed, thus denying them the rudder authority that they may have been hoping for.

 

I've tried to teach people to back right off, prior to any major manoeuvring, then power up again to provide steerage during the manoeuvre. It takes a lot of sinking in though, so to speak.

Edited March 15, 2016 by Loafer

[FadeToScarlet]

Relatively long, narrow ships, such as destroyers, do the same thing and can list or 'lean' outwards very noticeably in high speed turns. I can quite understand why people more used to handling boats on still, narrow waters like canals find this a bit disconcerting, but when it does happen then it's a sure indication that the boat speed through the water is much too fast for the highest rate of turn and the tightest possible radius of turn.

 

...it is good fun, though, making high speed destroyer turns!

[Loafer]

...it is good fun, though, making high speed destroyer turns!

 

Were you with Mr Smelly in the Arctic in the 70's?

[Tony Dunkley]

...it is good fun, though, making high speed destroyer turns!

 

Yes, I think so too, but most folk seem to to miss out on the fun aspect of it because they're too busy worrying about which part of the approaching lock walls they're going to crash into.

[billS]

Shouldn't this subject be moved to "current" affairs?

[twbm]

Narrowboat sideways across bridge. Waterway Authority has tug but it was too far away to wait for so Fire bobbies get on with it.

 

Well there's a thing...

[ditchcrawler]

Narrowboat sideways across bridge. Waterway Authority has tug but it was too far away to wait for so Fire bobbies get on with it.

 

Well there's a thing...

Because they didn't want to wait with 4 appliances until the tug arrived.

[ditchcrawler]

1-20 into this video shows how to go through a bridge with the flow

 

http://www.eafa.org.uk/catalogue/1415

Edited March 17, 2016 by ditchcrawler