TIGHT TURNING

[Swallowman]

Is it just me or do others find their boat responds much better to having the tiller at no more than 60 degrees to the straight ahead position? If I hold the tiller over at 90 degrees, bugger all seems to happen except lots of water thrashing out from both sides and going nowhere fast.

Lots of old film of working boats show the tiller at 90 degrees and I wonder if they know something I don't (!).

[Tam & Di]

Is it just me or do others find their boat responds much better to having the tiller at no more than 60 degrees to the straight ahead position? If I hold the tiller over at 90 degrees, bugger all seems to happen except lots of water thrashing out from both sides and going nowhere fast.

Lots of old film of working boats show the tiller at 90 degrees and I wonder if they know something I don't (!).

A standard rudder with a single screw boat is reckoned only to work effectively through about 70 degrees, i.e. 35 degrees either way from centre. After that it "spills" and the thrust is no longer being applied effectively to push the stern round. It does get a bit more complicated than that though.

 

Tam

[nicknorman]

Yes its definitely better not to have the rudder too far over. On our's it only goes to about 60 deg, and even then you have to ensure the flow is established when manoeuvring by centring the rudder for a moment until forward speed is established. If you look behind and see water coming around both sides of the rudder, you have got it too far over and/or need to momentarily centre to re-establish the correct flow.

 

I watched a long Anglo Welsh boat takes ages to wind - the rudder went to, and was being held, more than 90degrees and so not surprisingly they were having trouble making it turn at all!

Edited December 11, 2013 by nicknorman

[bottle]

What Tam said but a Schilling rudder does better.

 

http://en.wikipedia.org/wiki/Schilling_rudder

[Martin Megson]

I agree there seems to a point beyond which the prop wash is going to both sides. Not sure about older working boats but they tend to have a larger prop turning slower which may have an effect.

[Mike Tee]

But often the bigger boats can be seen being 'worked' round, ie. you'll see the operater using the rudder as a paddle to kick the stern round. Often seen by buttys turning after a motor - go on, I'm sure someone's got a link to a video of this.

[Paul C]

To get a nice tight turn its not so much how much tiller movement, but how you set it up. For example, if winding, then a lot of people make the mistake of approaching the winding hole, then slowing down as they start to turn. A normal narrowboat turns best during acceleration forwards, and worst when decelerating. What I do is approach the mid point (but near-ish the towpath, give enough room for the stern to swing round) slowly, give a small 'kick' of tiller, then reverse to a stop or a little backwards. The little kick starts the boat turning a bit, and is there just to save time (may as well get the boat turning while reversing) but doesn't do the bulk of the turn. Then once give it full power and full tiller, the boat spins nicely in a very tight turn. To turn in a really restricted size area, its more important to get the turn set up properly than anything else.

 

Another thing, if you can choose the direction of turn, choose it so the propwalk on reverse helps rather than hinders; or the flow of the canal/river helps, if this has more influence.

[Sbg]

But often the bigger boats can be seen being 'worked' round, ie. you'll see the operater using the rudder as a paddle to kick the stern round. Often seen by buttys turning after a motor - go on, I'm sure someone's got a link to a video of this.

I do that - discovered by accident a few years ago. We call it "rowing" :-)

[Paul C]

I do that - discovered by accident a few years ago. We call it "rowing" :-)

 

I was taught it but can't really explain if, or how it works. In my perception, it doesn't make a difference - maybe I'm doing it wrong? I'd have thought it was counterintuitive to working, after all it would give the effect of either paddling the boat forwards or your effective tiller angle would be the average of where it is during the tiller flapping. Maybe buttys (their steerers) do it to get some water flowing over the hull/rudder etc?

[nicknorman]

It works because you push the tiller over fast, and return it slowly. There is a non-linear relationship between the speed an object moves through the water, and the force required (or drag produced, if you like). Thus it takes more energy to push the tiller over fast, than it does to return it slowly (this is of course presuming the boat has no forward speed). This difference of energy translates into a different average force produced by the rudder in each direction, thus the stern is "pumped" round.

[bizzard]

If you, your rudder and tiller gear are strong enough you can propel your boat forwards by pulling and pushing the tiller from side to side hard and fast. Similar action as standing up sculling a dinghy along with one oar over the stern transom.

[nicknorman]

Actually biz I think I disagree. Sculling a dinghy only works because you rotate the oar as well as waggling it, thus changing its pitch so as to push water backwards without the corresponding pulling of water forwards.

[alan_fincher]

To get a nice tight turn its not so much how much tiller movement, but how you set it up. For example, if winding, then a lot of people make the mistake of approaching the winding hole, then slowing down as they start to turn. A normal narrowboat turns best during acceleration forwards, and worst when decelerating. What I do is approach the mid point (but near-ish the towpath, give enough room for the stern to swing round) slowly, give a small 'kick' of tiller, then reverse to a stop or a little backwards. The little kick starts the boat turning a bit, and is there just to save time (may as well get the boat turning while reversing) but doesn't do the bulk of the turn. Then once give it full power and full tiller, the boat spins nicely in a very tight turn. To turn in a really restricted size area, its more important to get the turn set up properly than anything else.

 

Another thing, if you can choose the direction of turn, choose it so the propwalk on reverse helps rather than hinders; or the flow of the canal/river helps, if this has more influence.

Blimey! All sounds horribly complicated!

 

Main trick is not to have too long a boat!

 

1) Approach turn slowly

2) Make sure you are close enough to bank you are turning away from that back end will just clear it.

3) Open up and turn around, never having disengaged forward gear at any point

 

Simple

 

 

EDIT:

 

But seriously.... That clip does clearly show me just for a few seconds at the start "working" the tiller to get a tighter turn. I have no doubt whatsoever it makes a difference, but in this case once I knew it would go round easily, it was easier to just brace myself against the cabin to keep the tiller held over, as, if I let it straighten again, with this much power on it is actually very hard work to keep pushing it back!

Edited December 11, 2013 by alan_fincher

[fudd]

What Tam said but a Schilling rudder does better.

 

http://en.wikipedia.org/wiki/Schilling_rudder

So does ours.

Edited December 11, 2013 by fudd

[bizzard]

Actually biz I think I disagree. Sculling a dinghy only works because you rotate the oar as well as waggling it, thus changing its pitch so as to push water backwards without the corresponding pulling of water forwards.

True, the boat would need two rudders and tillers set well apart, each rudder blade with as big as possible one way cat flap (only about a fiver in Wilcos) installed in them both that would shut on the power stroke and open on the back sweep to let water through and minimize the braking effect, grab a fresh blade full of water and shut as the power stroke begins. The boat will of course then have to be rowed with the tillers all bent around into comfortable positions for the rower.

[mark99]

So does ours.

 

 

Do you trouble cleaning your prop? I assume no weedhatch.

[fudd]

 

 

Do you trouble cleaning your prop? I assume no weedhatch.

It can be a bit of a pain. We do have a weed hatch, but its a bit of a reach. The main advantage of it though, is that it steers just as well in reverse. Wouldn't swap it for anything.

[nicknorman]

But presumably it doesn't really steer in neutral?

[bizzard]

 

 

Do you trouble cleaning your prop? I assume no weedhatch.

With a telescopic prop shaft which is arranged so its telescopic action can be unlocked and brought into action when you put the boat in astern gear. The fouled propeller will screw itself out backwards clear of the stern enabling you to lean out over the counter to clear it.

[fudd]

But presumably it doesn't really steer in neutral?

Do any of them?

[nicknorman]

Do any of them?

Yes, ours does pretty well. It's got a man sized Hudson rudder!

[fudd]

Yes, ours does pretty well. It's got a man sized Hudson rudder!

Piccy?

[MtB]

Is it just me or do others find their boat responds much better to having the tiller at no more than 60 degrees to the straight ahead position? If I hold the tiller over at 90 degrees, bugger all seems to happen except lots of water thrashing out from both sides and going nowhere fast.

Lots of old film of working boats show the tiller at 90 degrees and I wonder if they know something I don't (!).

 

Is it just me or do others find their boat responds much better to having the tiller at no more than 60 degrees to the straight ahead position? If I hold the tiller over at 90 degrees, bugger all seems to happen except lots of water thrashing out from both sides and going nowhere fast.

Lots of old film of working boats show the tiller at 90 degrees and I wonder if they know something I don't (!).

 

Well for a start working boats generally have no 'balance blade' section on the rudder forward of the rudder post, so when pushed over 90 degrees only 50% of the prop wash is obstructed leaving the other 50% available to apply a turning moment to the boat hull. With a modern rudder with 6" of balance blade forward of the rudder pin more like 80% of the blade output is caught, meaning at 90 degrees the turning moment is negligible.

 

OTOH at 60 or 70 degrees most of the blade flow is directed to one side with a modern rudder so this is consistent with your experience. It would be different without any balance blade.

 

Alan what is the rudder format on Sickle? Any balance blade present? I never find 'working' the tiller makes a blind bit of difference on Reg, with 6" of balance blade.

 

MtB

[nicknorman]

Piccy?

Sorry, can't find one of it out of the water.

[ditchcrawler]

If you, your rudder and tiller gear are strong enough you can propel your boat forwards by pulling and pushing the tiller from side to side hard and fast. Similar action as standing up sculling a dinghy along with one oar over the stern transom.

use to do that in sailing dinghies when the wing died