Bowthruster usage

[howardang]

1 hour ago, Tonka said:

The banks are in a state because they get washed away by plonker's using bow thrusters.  When a simple push is needed

Of course, no damage is caused to banks, including piling, by those who run their engines in gear for hours on end while alongside in order to charge their batteries?

Howard

[Hudds Lad]

We have one on our new boat, don’t really use it a great deal unless winding against the prevailing or reversing a long way, it’s nice to have it as an extra for peace of mind somehow. Give it the occasional blast to check it’s still working, remind myself which direction on the rocker switch does what, or scare the bejebus out of anyone sat in the bow who’s new to boats (more polite than a horn blast). I tend to sit on the side of the hatch to avoid standing for long periods and occasionally catch the switch with my foot which annoys the wife no end  

 

Have followed a boat in the past who used theirs exclusively on any corner rather than turn the tiller, after about the third bush they got stuck in we got by and left them to it.

 

To sort of answer the OP, when leaving the side i always give the front a good old shove then the back a lighter shove before i step on, then i can leave in tick without the back sticking to the side or using lots of revs and buffeting any boat behind like some seem to do.

[Alan de Enfield]

47 minutes ago, howardang said:

Of course, no damage is caused to banks, including piling, by those who run their engines in gear for hours on end while alongside in order to charge their batteries?

Howard

No its not as you are not running the engine with the prop engaged - it is forbidden to 'turn the prop' when alongside.

[Victor Vectis]

We took a holiday on VIC 32 earlier this year (Recommended! http://savethepuffer.co.uk/ )

 

I was impressed by the way she was handled moving off certain quaysides, ie: spring rope on the stern, engine in reverse and out swung the bow.

I'm going to try this where I can next time I'm on our boat.

Edited September 8, 2022 by Victor Vectis

[JamesFrance]

The only time one would have been useful for us would be for mooring in a marina, not a traditional part of the canals.   Would have saved the effort of poling when we had a long boat and a short wife.

[Tony1]

58 minutes ago, Alan de Enfield said:

No its not as you are not running the engine with the prop engaged - it is forbidden to 'turn the prop' when alongside.

 

I've seen a couple of boats doing exactly what Howard described, but I realise now that it couldn't have happened, because it is forbidden. 

The various engines and gennies I've heard running until 11pm and beyond never really happened either, because that's forbidden as well.

Its a good job those half a dozen speeding boats that passed this morning were actually forbidden from speeding, otherwise they might have been speeding and caused some damage to the banks.

And they definitely weren't plonkers, or indeed plonker's [sic], so it's all fine.  

 

Edited September 8, 2022 by Tony1

[Rob-M]

25 minutes ago, Victor Vectis said:

We took a holiday on VIC 32 earlier this year (Recommended! http://savethepuffer.co.uk/ )

 

I was impressed by the way she was handled moving off certain quaysides, ie: spring rope on the stern, engine in reverse and out swung the bow.

I'm going to try this where I can next time I'm on our boat.

That is how I move off the service point at Great Haywood marina especially when the wind is blowing.

[Jerra]

4 minutes ago, Rob-M said:

That is how I move off the service point at Great Haywood marina especially when the wind is blowing.

It always seems to be blowing when I have been there.

[IanD]

18 minutes ago, Jerra said:

It always seems to be blowing when I have been there.

 

There are occasions when bow thrusters are genuinely useful and no amount of steering skill will help, for example crosswinds or crosscurrents in restricted spaces where you can't get the stern across to push the bows over, and there's nobody in the bows with a pole or on the bank with a rope.

 

There are more frequent times where one would be useful to get the boat out of a position that it's got into through lack of attention or skill, where tutting from I-don't-need-a-bow-thuster boaters is not helpful.

 

There are also times when a bow thruster just makes things easier, for example when reversing long distances especially in narrow channels lined with boats.

 

But obviously using one just to steer in normal circumstances instead of using the rudder is *completely* beyond the pale... 😉

[Rob-M]

36 minutes ago, Jerra said:

It always seems to be blowing when I have been there.

Yes, so plenty of opportunity to practice.

[system 4-50]

When I'm Prime Minister (don't laugh, it been shown recently almost anybody can do it), I will make it mandatory for all hire narrowboats to have a large red button marked "bowthruster" next to the instrument panel.  When pushed it will make an unpleasant loud graunching noise but do nothing else.  Thus hirers who move on to ownership will have been conditioned to avoid pushing similar buttons.

[Tony1]

21 minutes ago, system 4-50 said:

When I'm Prime Minister (don't laugh, it been shown recently almost anybody can do it), I will make it mandatory for all hire narrowboats to have a large red button marked "bowthruster" next to the instrument panel.  When pushed it will make an unpleasant loud graunching noise but do nothing else.  Thus hirers who move on to ownership will have been conditioned to avoid pushing similar buttons.

 

This is the kind of namby-pamby approach that will just make things worse. 

We need to get serious about this. All bow thruster buttons should be electrified.

Nothing lethal, of course (for a first offence). Something akin to a police taser would do the trick. 

That way these incompetent layabouts will still have the option to use their infernal bow thrusters. But if they do press that button, its going to really liven up their morning. 

 

 

Edited September 8, 2022 by Tony1

[Richard10002]

16 hours ago, Wanderer Vagabond said:

's funny but over the years I've decided that it isn't the bow that I want to get away from the reedy weedy banks but the stern. If you can get your stern into the middle of the cut (where it should normally be at it's deepest) with a clear prop you can do what you like. If however you push the bow out, because of the rotation of the boat around it's central point, it logically means that the stern will then go into those weedy, reedy banks that you are trying to get away from, only now you have the weedy, reedy bits around your prop

Surely, if you want to get the stern out, you push the tiller away from the bank and engage forward gear. It works just like a bowthruster at the stern.

[Wanderer Vagabond]

56 minutes ago, Richard10002 said:

Surely, if you want to get the stern out, you push the tiller away from the bank and engage forward gear. It works just like a bowthruster at the stern.

Yup, that is one way of doing it. The other is to shove the stern away from the bank manually and then engage reverse gear which then pushes water between your boat and the bank taking the whole boat away from the side. When you then engage forward drive the bow is already away from the bank so it will only take a small turn to continue on your way. The method you suggest means that the bow is still tight in to the bank so to steer it away you then have to push the tiller towards the bank which means that as the bow comes out, the stern goes in, back into the shallows and weeds.

[howardang]

3 hours ago, Tony1 said:

 

I've seen a couple of boats doing exactly what Howard described, but I realise now that it couldn't have happened, because it is forbidden. 

The various engines and gennies I've heard running until 11pm and beyond never really happened either, because that's forbidden as well.

Its a good job those half a dozen speeding boats that passed this morning were actually forbidden from speeding, otherwise they might have been speeding and caused some damage to the banks.

And they definitely weren't plonkers, or indeed plonker's [sic], so it's all fine.  

 

I think Alan just forgot the "Tongue in Cheek" Emoji.

 

Howard

[IanD]

20 minutes ago, Wanderer Vagabond said:

Yup, that is one way of doing it. The other is to shove the stern away from the bank manually and then engage reverse gear which then pushes water between your boat and the bank taking the whole boat away from the side. When you then engage forward drive the bow is already away from the bank so it will only take a small turn to continue on your way. The method you suggest means that the bow is still tight in to the bank so to steer it away you then have to push the tiller towards the bank which means that as the bow comes out, the stern goes in, back into the shallows and weeds.

 

Or if you don't mind being abused by the "new technology is bad" school and you have both a bow thruster *and* a Schilling rudder, you can move both ends of the boat away from the bank in parallel at the same time without moving forwards or backwards... 😉

Edited September 8, 2022 by IanD

[Tony1]

3 minutes ago, howardang said:

I think Alan just forgot the "Tongue in Cheek" Emoji.

 

Howard

 

Aaaah, I see. Oh dear.

In that case I owe Alan an apology for my overly sarcastic reply. 

 

 

Edited September 8, 2022 by Tony1

[Tony1]

11 minutes ago, IanD said:

 

Or if you don't mind being abused by the "new technology is bad" school and you have both a bow thruster *and* a Schilling rudder, you can move both ends of the boat away from the bank in parallel at the same time without moving forwards or backwards... 😉

 

Dammit man, there's only one kind of shilling we'll tolerate in this country, and its not spelled with a 'C'.

And there are 21 of them to a Queen's guinea, by God.

Why don't you just fit VTOL jet engines on the boat, and be done with it? 

 

(but seriously though- if they ever figure out that VTOL thing for narrowboats, do let me know. That would be the coolest thing ever)

 

Edited September 8, 2022 by Tony1

[Wanderer Vagabond]

4 minutes ago, IanD said:

 

Or if you don't mind being abused by the "new technology is bad" school and you have both a bow thruster *and* a Schilling rudder, you can move both ends of the boat away from the bank in parallel at the same time... 😉

Getting more technical now (had to look up a Schilling rudder) but I would have thought that having a bulbous shaped rudder (Schilling) would increase drag when travelling in a straight line wouldn't it? (isn't that why F1 cars have a DRG system?) Surely a twin flat rudder would have a better effect (not having seen either on a narrow boat though).

[Tracy D'arth]

6 minutes ago, Wanderer Vagabond said:

Getting more technical now (had to look up a Schilling rudder) but I would have thought that having a bulbous shaped rudder (Schilling) would increase drag when travelling in a straight line wouldn't it? (isn't that why F1 cars have a DRG system?) Surely a twin flat rudder would have a better effect (not having seen either on a narrow boat though).

Kort rudder, best of both worlds.

[IanD]

23 minutes ago, Wanderer Vagabond said:

Getting more technical now (had to look up a Schilling rudder) but I would have thought that having a bulbous shaped rudder (Schilling) would increase drag when travelling in a straight line wouldn't it? (isn't that why F1 cars have a DRG system?) Surely a twin flat rudder would have a better effect (not having seen either on a narrow boat though).

The drag increase is tiny (especially at low speeds like on the canals), just like it is for an aeroplane aerofoil. In fact it can be zero, because the Schilling rudder has more lift (sideways thrust) for a given size, so you can use a smaller rudder -- mine is about 500mm long compared to about 700mm for a flat plate rudder, see drawing (from Schilling patent).

 

Twin flat rudders still don't work at large angles because the water flow breaks away from them (stalling), the Schilling rudder works up to much bigger angles by keeping the water flow attached to the rear side.

 

15 minutes ago, Tracy D'arth said:

Kort rudder, best of both worlds.

 

Kort rudders (or nozzles, to be more accurate) work very well in low-speed marine applications like tugs. On a canal they're very prone to getting jammed by weeds or canal debris because of the small clearance between propeller and nozzle... 😞

Edited September 8, 2022 by IanD

[Wanderer Vagabond]

8 minutes ago, IanD said:

The drag increase is tiny, just like it is for an aeroplane aerofoil. In fact it can be zero, because the Schilling rudder has more lift (sideways thrust) for a given size, so you can use a smaller rudder -- mine is about 500mm long compared to about 700mm for a flat plate rudder.

 

Twin flat rudders still don't work at large angles because the water flow breaks away from them (stalling), the Schilling rudder works up to much bigger angles by keeping the water flow attached to the rear side.

 

 

Kort rudders (or nozzles, to be more accurate) work very well in low-speed marine applications like tugs. On a canal they're very prone to getting jammed by weeds or canal debris because of the small clearance between propeller and nozzle... 😞

I would need convincing that the drag increase would be zero just because the rudder size is smaller since with a conventional rudder it will be the leading edge and thickness that creates the drag rather than the length of rudder. I was thinking that since water is a bit heavier than air, displacing the flow by having a bulbous rudder would lead to some increase in drag. Since my boat isn't highly powered in the first place, I'm not sure I'd want to.

[IanD]

29 minutes ago, Wanderer Vagabond said:

I would need convincing that the drag increase would be zero just because the rudder size is smaller since with a conventional rudder it will be the leading edge and thickness that creates the drag rather than the length of rudder. I was thinking that since water is a bit heavier than air, displacing the flow by having a bulbous rudder would lead to some increase in drag. Since my boat isn't highly powered in the first place, I'm not sure I'd want to.

 

Rudder drag has two components, profile drag and skin drag. If you want to go and dig through all the academic papers on rudder design they show almost no drag increase for aerofoil rudders when straight ahead, and some increase as deflection increases -- however this is just rudder drag, which is orders of magnitude smaller than hull drag, so the overall drag increase on the boat is negligible. You also need to bear in mind that the rudder isn't just being dragged through the water, the rapidly rotating wash from the prop hits it, and a bulbous leading edge rather than a sharp one helps to straighten this flow out without turbulence or flow separation as it passes the rudder.

 

At low speeds (like narrowboats, or slow planes) thicker profiles are used to get more lift with very little drag increase -- the one I posted was a 20% profile, but even 25% has been used for low-speed ships. At high speeds like supersonic planes or planing boats the tradeoff is different and much thinner profiles are used (e.g. 5% or less), but this doesn't matter for the canals 🙂

Edited September 8, 2022 by IanD

[Bee]

7 hours ago, MtB said:

 

 

I'm surprised you say this as I've never had a bow thruster and rarely have any problem hovering about mid cut when the need arisies. In fact I quite enjoy doing it. On a river it's even easier with a bit of current. Maybe its easier in a narrow boat than a proper boat-shaped boat like Bee.

 

 

Actually I quite like doing it as well, I think Bee is a bit prone to going round in circles though because the wheelhouse is nearer the front than the back, a puff of wind and it needs quite a big movement to get the back end to catch up, in fact if its a bit breezy the best thing to do is just point the front into the wind. Quite often the whole shambolic affair is rescued by the skill of the person who flings a rope over something attached to the bank.

[Wanderer Vagabond]

7 hours ago, MtB said:

 

 

I'm surprised you say this as I've never had a bow thruster and rarely have any problem hovering about mid cut when the need arisies. In fact I quite enjoy doing it. On a river it's even easier with a bit of current. Maybe its easier in a narrow boat than a proper boat-shaped boat like Bee.

 

 

The only rider I'd make on that is that when it's windy all rules go out of the window.

 

On the river however, as you say, it is even easier if there is some flow since you just match engine speed to flow and hold station or even ferry glide (https://www.rya.org.uk/e-news/up-to-speed/mastering-the-ferry-glide)