Reversing

[KezzerN]

I am trying to get my head around reversing, something that isn't my strong point hence my interest in rudders/propellers.  I have come across this video on youtube and wondered if everything said here is applicable to narrowboats: 

 

 

 

 

And this is the video that got me asking the question about fishtail rudders:

 

 

 

 

 

 

 

Edited March 13 by KezzerN

[IanD]

Most ships (and all narrowboats) have poorer steering in reverse, sometimes to the point of being pretty much unsteerable -- the reason is largely that when going ahead the prop pushes a high-speed (rotating) jet of water over the (carefully-shaped to maximise lift) rudder to get effective steering, when going astern it pulls water more slowly past the (now wrongly-shaped -- especially with a twisted leading edge like the one shown!) rudder and the fast water jet hits the swim where it does nothing to help steering.

 

The other problem with narrowboats is people tend -- understandably! -- to go slowly in reverse, when steering is even less effective (just like when going ahead), which makes things even worse. If the boat is moving slowly the rudder doesn't do much in reverse even when pushed over quite a long way.

 

A far easier way of steering in reverse is to keep the tiller central and move the bows across using a bow thruster***, especially if this is throttleable like some modern ones instead of just being on(howl!)/off. Of course the purists disapprove of this (also BT in general), largely on the grounds that "they didn't have them in the old days" -- OTOH they didn't have electric lighting or TV or the internet then, but they seem quite happy to use these today... 😉 

 

*** of course using a BT to steer when going ahead instead of the tiller like some newbies -- especially in wideboats -- seem to do is completely beyond the pale... 🙂

Edited March 13 by IanD

[KezzerN]

 

Thanks for the explanation IanD.  I figure I will get there one day and actually be able to reverse without going into panic mode!

[nicknorman]

If you have a bow thruster it’s easy. If you don’t it can be hard, but different narrowboats have different handling characteristics so it’s mostly about getting to understand your boat.

 

But I think as a general point, one factor that makes narrowboats hard to reverse is the absence of any sort of keel and the very shallow draft at the bow vs deeper draft at the stern. Annoyingly, when reversing the bow is quite happy to skitter sideways across the water due to it only being a few inches in the water, whereas the much deeper stern prefers to go straight through the water. This means that any slight tendency to turn gradually increases as the bow tries to overtake the stern!

 

Another thing I would mention, in contradiction to the first video, is that when changing from astern to ahead to kick the stern round, start out with the tiller straight and then after a couple of seconds once the water flow is established, move the tiller over, and not too far. Putting it into ahead when the tiller is already hard over causes the rudder to stall in the water flow - you will see water flow coming out both sides of the rudder, not just on the desired side and thus it is less effective. I always look at the water flow out the back when doing this sort of thing

Finally there can be disruption caused by water circulating in the gap between the boat and the bank, made worse if it’s shallow. So if things are going really badly, stop and wait for the currents to subside (which takes a surprisingly long time) and then have another go.

Edited March 13 by nicknorman

[Laurie Booth]

3 minutes ago, KezzerN said:

 

Thanks for the explanation IanD.  I figure I will get there one day and actually be able to reverse without going into panic mode!

Good luck, I still can't reverse after 60 years of boating.

 

[Rod Stewart]

5 minutes ago, KezzerN said:

 

Thanks for the explanation IanD.  I figure I will get there one day and actually be able to reverse without going into panic mode!

There is no substitute for practice practice practice. Some boats steer better in reverse than others, some are a right PITA. Throw in a bit of wind and flow and it can be nigh on impossible.

 

Concentrate on looking at which way the bow is turning, and correcting it by application of forward movement before continuing to reverse will often give better results than trying to steer in reverse.

 

But my best advice is go out and practice. Preferably on a calm day in deep water with not too many things in the way to hit, and understand what difference propwalk can make, in particular in close proximity to the bank.

1 minute ago, Laurie Booth said:

Good luck, I still can't reverse after 60 years of boating.

 

Yeah, but you are great at directing Daleks.

Edited March 13 by Rod Stewart

[Tonka]

Practice is the answer

[Laurie Booth]

1 minute ago, Rod Stewart said:

There is no substitute for practice practice practice. Some boats steer better in reverse than others, some are a right PITA. Throw in a bit of wind and flow and it can be nigh on impossible.

 

Concentrate on looking at which way the bow is turning, and correcting it by application of forward movement before continuing to reverse will often give better results than trying to steer in reverse.

 

But my best advice is go out and practice. Preferably on a calm day in deep water with not too many things in the way to hit, and understand what difference propwalk can make, in particular in close proximity to the bank.

Yeah, but you are great at directing Daleks.

[KezzerN]

7 minutes ago, nicknorman said:

If you have a bow thruster it’s easy. If you don’t it can be hard, but different narrowboats have different handling characteristics so it’s mostly about getting to understand your boat.

 

 

 

Thanks for the input NickNorman, I have been watching as many videos as possible on reversing, but as you say, different narrowboats have different handling characteristics and my boat just does not behave like theirs!

[IanD]

9 minutes ago, nicknorman said:

If you have a bow thruster it’s easy. If you don’t it can be hard, but different narrowboats have different handling characteristics so it’s mostly about getting to understand your boat.

 

But I think as a general point, one factor that makes narrowboats hard to reverse is the absence of any sort of keel and the very shallow draft at the bow vs deeper draft at the stern. Annoyingly, when reversing the bow is quite happy to skitter sideways across the water due to it only being a few inches in the water, whereas the much deeper stern prefers to go straight through the water. This means that any slight tendency to turn gradually increases as the bow tries to overtake the stern!

 

Another thing I would mention, in contradiction to the first video, is that when charging from astern to ahead to kick the stern round, start out with the tiller straight and then after a couple of seconds once the water flow is established, move the tiller over, and not too far. Putting it into ahead when the tiller is already hard over causes the rudder to stall in the water flow - you will see water flow coming out both sides of the rudder, not just on the desired side and thus it is less effective. I always look at the water flow out the back when doing this sort of thing

Finally there can be disruption caused by water circulating in the gap between the boat and the bank, made worse if it’s shallow. So if things are going really badly, stop and wait for the currents to subside (which takes a surprisingly long time) and then have another go.

 

A properly ballasted boat will only have a small difference in draft between bow and stern, just like fully-loaded boats in the old days. However many boats today swim very bow high, either because nobody bothered about this when ballasting or the owner wants the boat to look like a lightly-loaded traditional boat -- and as you say these do steer even worse when going astern... 😞 

 

(steering and wake are also better going ahead when ballasted almost level, for different reasons...)

 

For whatever reason, some boats are just unsteerable wallowing pigs when going astern... 😞 

Edited March 13 by IanD

[KezzerN]

8 minutes ago, Laurie Booth said:

Good luck, I still can't reverse after 60 years of boating.

 

 

 

Glad I am not the only one that struggles! 

[koukouvagia]

When I had Owl the slow revving Kelvin coupled with a large propeller meant that the paddle-wheel effect was noticeable.

On Hampton, which has a hydraulic motor in the rudder -like a giant outboard- I can reverse as easily as I can go forwards.

Recently I was on the trip boat Birdswood which has a similar system.  Because there was no convenient winding hole, the steerer reversed back to the mooring - a distance of over a mile.

[KezzerN]

8 minutes ago, Rod Stewart said:

There is no substitute for practice practice practice. Some boats steer better in reverse than others, some are a right PITA. Throw in a bit of wind and flow and it can be nigh on impossible.

 

Concentrate on looking at which way the bow is turning, and correcting it by application of forward movement before continuing to reverse will often give better results than trying to steer in reverse.

 

But my best advice is go out and practice. Preferably on a calm day in deep water with not too many things in the way to hit, and understand what difference propwalk can make, in particular in close proximity to the bank.

 

 

 

Every time I go to practice anything every boat on the canal network appears! 

[Tony Brooks]

What has not been mentioned is the interaction between the prop wash in reverse, the boat's swim and the canal profile.

 

With all else being equal the prop trust in reverse pushes a cone of high speed water towards the front of the boat, the swim splits it and more or less, but not exactly because the one is rotating, equally either side of the swim. But in a canal, especially a shallow one where water does not have much space to flow between the baseplate, if you get too close to the side of the main channel the water passing down on that side of the swim is likely to push the stern away from the channel edge. On its own that is not so bad, but in doing it the boat pivots and turn the bow away from that channel edge, so it is all too easy to end up diagonally across the canal.

 

You get a similar effect in a wide lock if you apply too much reverse, the stern of the boat gets pushed away from the lock wall.

 

I am with those who always (bar one) have proems in reversing. The bar one was reversing down the Ellesmere arm with the wind straight onto the bow. The wind kept the boat straight.

[KezzerN]

4 minutes ago, Tony Brooks said:

What has not been mentioned is the interaction between the prop wash in reverse, the boat's swim and the canal profile.

 

With all else being equal the prop trust in reverse pushes a cone of high speed water towards the front of the boat, the swim splits it and more or less, but not exactly because the one is rotating, equally either side of the swim. But in a canal, especially a shallow one where water does not have much space to flow between the baseplate, if you get too close to the side of the main channel the water passing down on that side of the swim is likely to push the stern away from the channel edge. On its own that is not so bad, but in doing it the boat pivots and turn the bow away from that channel edge, so it is all too easy to end up diagonally across the canal.

 

You get a similar effect in a wide lock if you apply too much reverse, the stern of the boat gets pushed away from the lock wall.

 

I am with those who always (bar one) have proems in reversing. The bar one was reversing down the Ellesmere arm with the wind straight onto the bow. The wind kept the boat straight.

 

 

Thanks for the extra input Tony.  Some of the videos, like the Willow Wren Training one make it look so easy!

 

[Rob-M]

Success at reversing is linked to how many people are watching, the more watching the worse it will be.

 

The best thing to do is find a quiet stretch of canal and practice but remember, no two days are likely to be the same as once in reverse the boat has a mind of its own.

 

When reversing keep an eye on the bows and if they start going off line stop and use forward to get them back in position and then start again.

[Tony Brooks]

1 minute ago, KezzerN said:

 

 

Thanks for the extra input Tony.  Some of the videos, like the Willow Wren Training one make it look so easy!

 

 

Well they would, wouldn't they😀

[nicknorman]

1 minute ago, IanD said:

 

A properly ballasted boat will only have a small difference in draft between bow and stern, just like fully-loaded boats in the old days. However many boats today swim very bow high, either because nobody bothered about this when ballasting or the owner wants the boat to look like a lightly-loaded traditional boat -- and as you say these do steer even worse when going astern... 😞 

 

(steering and wake are also better going ahead when ballasted almost level, for different reasons...)

Depends on what you mean by “properly ballasted!” Having a lightly ballasted bow has its advantages eg when winding at a silted up winding hole (aren’t they all silted up?) and other times you want to poke the bow into somewhere shallow. Also means that the front of the boat can get into the side even if the stern can’t, so one can easily get on and off the boat. Steve Hudson built well deck boats like ours that were shallow at the front, whereas his tug deck boats were the same hull shape but ballasted down much more at the front. You can take your pick…

[KezzerN]

3 minutes ago, Rob-M said:

 

The best thing to do is find a quiet stretch of canal and practice but remember, no two days are likely to be the same as once in reverse the boat has a mind of its own.

 

The devil grabs the bow and laughs!

[Mike Tee]

There is no alternative to practice.  I've got many years of experience in many different boats and I can reverse fine - until I can't! No apparent reason for suddenly failing, but I'm sure it must be something to do with the depth / shape of the canal or how close I am to the bank. Couldn't possibly be my fault 🙃!

Just keep on practicing but one thing for sure, do it in slow motion. The faster you try to go, the quicker it will go wrong, and the more difficult it will be to recover.

[IanD]

2 minutes ago, nicknorman said:

Depends on what you mean by “properly ballasted!” Having a lightly ballasted bow has its advantages eg when winding at a silted up winding hole (aren’t they all silted up?) and other times you want to poke the bow into somewhere shallow. Also means that the front of the boat can get into the side even if the stern can’t, so one can easily get on and off the boat. Steve Hudson built well deck boats like ours that were shallow at the front, whereas his tug deck boats were the same hull shape but ballasted down much more at the front. You can take your pick…

 

There are indeed some advantages to having a shallow bow and a deep stern -- but steerability (which was the subject) isn't one of them, especially in reverse as you pointed out, and neither is how the boat swims in shallow water -- of which there is far too much due to inadequate dredging... 😞 

 

Everything in narrowboat design is a compromise, whatever you do has advantages and disadvantages, you just need to decide what is best for you... 😉 

[David Mack]

Some boats are just impossible to steer in reverse. But if you are going to be successful you need to keep the bow and the stern in mid channel all the time. As soon as the bow drifts off you have lost it and have to go through all the fowards/backwards stuff to get back into mid channel, while making no progress in the direction you want to go.

Remember when reversing, point the tail end of the rudder towards where you want the stern to go. You may need to hold the rudder at an angle of 30-45 degrees to achieve this, and it can be hard work holding it there when it wants to slam round to 90 degrees. Keep looking at the bow and adjust the rudder angle to counteract any tendency for it to go to one side. For some people the direction to steer is intuitive, other people really struggle with it, and doing the opposite to what you should do when reversing is usually a whole lot worse than when the same happens going forwards!

Find a nice straight wide deepish section of canal with no moored boats and practice. It's the only way.

[KezzerN]

Talking of slamming around to 90 degrees, I am amazed at the number of people that sit on the seat right beside the tiller while driving considering it is so dangerous to do that.

[Alan de Enfield]

32 minutes ago, KezzerN said:

 

The devil grabs the bow and laughs!

 

I'd have thought some of our knowledgable blue water sailing members (Gobby-ho or Lady G) might have mentioned drogues - but it seems not. No one has mentioned this 'old fashioned' (almost always 100% successful) method.

 

A drogue anchor is a matter of a few £s and is simply a small parachute on a line - a home made alternative is to use a bucket on a rope - throw it over board with something like a 20-30 foot line,

 

As you reverse, the bucket is towed along (in the water, not on the bottom) and holds the bow straight. Yes it works well in a canal !

 

It is a life saving device used at sea - if you have an engine failure or are demasted you need to keep your 'head' into the waves, if you turn sideways, the waves roll you over and you sink and die.

 

Osculati Sea Drogue Anchor 530x600mm <special id="1" />6m Boats

 

The waves, wind, tides are making you go backwards (equivalent to being in reverse) and the drogue keeps the bow straigh in line :

 

[IanD]

4 minutes ago, Alan de Enfield said:

 

I'd have thought some of our knowledgable blue water sailing members (Gobby-ho or Lady G) might have mentioned drogues - but it seems not. No one has mentioned this 'old fashioned' (almost always 100% successful) method.

 

A drogue anchor is a matter of a few £s and is simply a small parachute on a line - a home made alternative is to use a bucket on a rope - throw it over board with something like a 20-30 foot line,

 

As you reverse, the bucket is towed along (in the water, not on the bottom) and holds the bow straight. Yes it works well in a canal !

 

It is a life saving device used at sea - if you have an engine failure or are demasted you need to keep your 'head' into the waves, if you turn sideways, the waves roll you over and you sink and die.

 

Osculati Sea Drogue Anchor 530x600mm <special id="1" />6m Boats

 

The waves, wind, tides are making you go backwards (equivalent to being in reverse) and the drogue keeps the bow straigh in line :

 

 

Given the amount of cr*p and debris in many UK canals, especially towards the bottom where a drogue (or bucket, or whatever...) is likely to drag and pick this up, I suspect this idea is unusable even if it works fine in deep open waters like the helpful drawing shows... 😉 

Edited March 13 by IanD