Boat veering to starboard

[Stedman II]

When under power, our boat goes in a straight line when the tiller/rudder is also straight. When we take the power off (i.e in neutral) and leave the tiller alone, the boat heads off to starboard. It did this twice yesterday in long bridgeholes, with the danger of scraping the handrails. The boat lists slightly to port. Is the veer to starboard a likely consequence of the list?

[Richard10002]

The opposite of the OP in that I have an effect when the prop is turning, but none when it is stopped:

Under power ahead with the tiller and rudder straight, the prop wash leaves the boat at an angle to port, thus pushing the stern slightly to starboard, and a tendency to turn to port. A slight pressure on the tiller, and no more, is enough to counteract this, but the direction of the wash doesnt change.

I dont really know what causes this, and am not concerned about it, but I always put it down to a bit of prop walk?

[Rebotco]

2 hours ago, Stedman II said:

When under power, our boat goes in a straight line when the tiller/rudder is also straight. When we take the power off (i.e in neutral) and leave the tiller alone, the boat heads off to starboard. It did this twice yesterday in long bridgeholes, with the danger of scraping the handrails. The boat lists slightly to port. Is the veer to starboard a likely consequence of the list?

Would this be a banana boat? 

[David Schweizer]

Yes prop walk, which will push the boat to port if rotation is clockwise and to starboard if rotation is anticlockwise. Whilst the degree to which it will do this varies from one boat to another, it is perfectly normal.

When I undertook my MCA Boatmasters licence practical test, the examiner required me to demonstrate steering the boat using prop walk only, not for any distance, only to get the boat into the bank.

[X Alan W]

The OP states his boat is OK under power it's when he shuts off he has a problem ;If in fact he engages neutral & has his problem it wouldn't be prop walk, but if it's still in gear at low revs it probably is posibly also harder to move the tiller one way than the other due to the direction of prop rotation could also be affected by the amount of rudder blade forward of the rudder post & rudder balance & self centering effect of the rudder.

[David Schweizer]

5 minutes ago, X Alan W said:

The OP states his boat is OK under power it's when he shuts off he has a problem ;If in fact he engages neutral & has his problem it wouldn't be prop walk, but if it's still in gear at low revs it probably is posibly also harder to move the tiller one way than the other due to the direction of prop rotation could also be affected by the amount of rudder blade forward of the rudder post & rudder balance & self centering effect of the rudder.

Yes I agree, I thought he meant reducing engine speed when he said "take the power off" not going into neutral. In neutral the rudder would have limited influence on steeing in any direction

[mross]

I don't normally let go of the tiller when the boat is moving!  I suspect most boats would veer slightly to port or starboard unless it was a windless day.

[alan_fincher]

7 minutes ago, David Schweizer said:

Yes I agree, I thought he meant reducing engine speed when he said "take the power off" not going into neutral.

 

But he did actually say

 

When we take the power off (i.e. in neutral).

 

I can't think of any obvious reason for the symptoms as he describes them, but obviously as has been suggested you may not have much steering effect at all if fully in neutral.  With a deep draughted boat on canals where the bridge holes have a lot of debris in, it is often recommended to come out of gear as you pass through, which has the effect of the back end ceasing to be pulled down, and more likely to ride over obstructions, and I often do this with either boat.  However the downside is you are not left with much steerage, although I find you tend to be kept away from the edges by the water  you are displacing to either side.

 

[alan_fincher]

4 minutes ago, mross said:

I don't normally let go of the tiller when the boat is moving!  I suspect most boats would veer slightly to port or starboard unless it was a windless day.

Highly dependent on boat length, or at least it is with ours.

Both my boats were orifginally built by Yarwoods in 1936 as full length (71'6") boats, but "Sickle was quickly cut to 40' to make an ice boat.

With the full length boat you can let go of the tiller, walk the gunwale, and go into the engine room for a quick check, and return to the steering position, usually with nothing dramatic happening.  However with "Sickle" if I try to put a coat on at the tiller, it is usually aimed straight at the bank long before I can get one arm down one sleeve.

[X Alan W]

15 minutes ago, alan_fincher said:

 

But he did actually say

 

When we take the power off (i.e. in neutral).

 

I can't think of any obvious reason for the symptoms as he describes them, but obviously as has been suggested you may not have much steering effect at all if fully in neutral.  With a deep draughted boat on canals where the bridge holes have a lot of debris in, it is often recommended to come out of gear as you pass through, which has the effect of the back end ceasing to be pulled down, and more likely to ride over obstructions, and I often do this with either boat.  However the downside is you are not left with much steerage, although I find you tend to be kept away from the edges by the water  you are displacing to either side.

 

A brief "Chuck Back" when the engine "ole" bulk head is just about to enter the bridge "ole" is often useful, engaging forward gear as the counter exits the  arch narrows is often a way to keep the prop clear of c**p

[alan_fincher]

6 minutes ago, X Alan W said:

A brief "Chuck Back" when the engine "ole" bulk head is just about to enter the bridge "ole" is often useful, engaging forward gear as the counter exits the  arch narrows is often a way to keep the prop clear of c**p

I find it is when "chucking back" that I am most likely to get a blade full though. 

It was doing exactly this before a Nuneaton bridge hole that resulted in us spending many hours trying to remove the "duvet from hell".

[X Alan W]

17 minutes ago, alan_fincher said:

Highly dependent on boat length, or at least it is with ours.

Both my boats were orifginally built by Yarwoods in 1936 as full length (71'6") boats, but "Sickle was quickly cut to 40' to make an ice boat.

With the full length boat you can let go of the tiller, walk the gunwale, and go into the engine room for a quick check, and return to the steering position, usually with nothing dramatic happening.  However with "Sickle" if I try to put a coat on at the tiller, it is usually aimed straight at the bank long before I can get one arm down one sleeve.

If the boat & I'm quoting full length is loaded/ballasted down by the head(fore end slightly deeper in the water than the stern) in days gone by it would follow the then distinct channel made by loaded boats & it would steer its self for a good distance without any input from the steerer, since the introduction of shorter length shallower draft leisure boats being able to cut corners & wander about over all the width of the canal + the lack of dredging I understand the channel has all but disappeared.

[X Alan W]

6 minutes ago, alan_fincher said:

I find it is when "chucking back" that I am most likely to get a blade full though. 

It was doing exactly this before a Nuneaton bridge hole that resulted in us spending many hours trying to remove the "duvet from hell".

I have to admit it's some years since I boated in a deep drafted boat so perhaps the bridge 'ole' c**p has built up or differs in composition so a float through in neutral may be a better idea (Horses for courses)It seems a shame that deep boats are considered a ( Pain in the a**e )whe encouraging them would make boating better for all boat depth requirements.

[David Schweizer]

50 minutes ago, alan_fincher said:

 

But he did actually say

 

When we take the power off (i.e. in neutral).

 

I can't think of any obvious reason for the symptoms as he describes them, but obviously as has been suggested you may not have much steering effect at all if fully in neutral.  With a deep draughted boat on canals where the bridge holes have a lot of debris in, it is often recommended to come out of gear as you pass through, which has the effect of the back end ceasing to be pulled down, and more likely to ride over obstructions, and I often do this with either boat.  However the downside is you are not left with much steerage, although I find you tend to be kept away from the edges by the water  you are displacing to either side.

 

Yes, I missed that ! 

[alan_fincher]

2 minutes ago, X Alan W said:

I have to admit it's some years since I boated in a deep drafted boat so perhaps the bridge 'ole' c**p has built up or differs in composition so a float through in neutral may be a better idea (Horses for courses)It seems a shame that deep boats are considered a ( Pain in the a**e )whe encouraging them would make boating better for all boat depth requirements.

 

2 minutes ago, X Alan W said:

I have to admit it's some years since I boated in a deep drafted boat so perhaps the bridge 'ole' c**p has built up or differs in composition so a float through in neutral may be a better idea (Horses for courses)It seems a shame that deep boats are considered a ( Pain in the a**e )whe encouraging them would make boating better for all boat depth requirements.

The trouble these days with ex working boats is that it is often very easy to find out what was not a "good idea", but sometimes only when you have done it.

For example trying to reverse through the disused stop lock between Salford Junction and Star City seemed a reasonable enough idea until I picked up a blade full that was still not removed several hours later.

I even managed to be polite to the "helpful" guy who came along and said "would,'t you be better off trying to do that through the weed hatch", though!

[mross]

14 hours ago, Stedman II said:

When we take the power off (i.e in neutral) and leave the tiller alone, .................

He is talking about neutral, not just slowing down.

[PaulG]

14 hours ago, Stedman II said:

When under power, our boat goes in a straight line when the tiller/rudder is also straight. When we take the power off (i.e in neutral) and leave the tiller alone, the boat heads off to starboard. It did this twice yesterday in long bridgeholes, with the danger of scraping the handrails. The boat lists slightly to port. Is the veer to starboard a likely consequence of the list?

IHMO yes.
When I sailed dinghies I did a few "rudderless" races. You steer by heeling the boat one way or the other.

A list to port would cause the boat to steer to starboard, and vice versa.

[ditchcrawler]

3 hours ago, mross said:

I don't normally let go of the tiller when the boat is moving!  I suspect most boats would veer slightly to port or starboard unless it was a windless day.

Mine use to turn quite sharply in ether direction if I let go the tiller while under power, I chopped an inch off the leading edge of the rudder to sort it.

[Stedman II]

Perhaps I should not have said 'leave the tiller alone'. What I meant was 'keep hold of the tiller, but don't move it'. The tiller remains dead centre, the prop is not turning, but the boat veers to starboard. The sailing analogy is useful - I think it must be the list that causes the problem.

[ditchcrawler]

1 minute ago, Stedman II said:

Perhaps I should not have said 'leave the tiller alone'. What I meant was 'keep hold of the tiller, but don't move it'. The tiller remains dead centre, the prop is not turning, but the boat veers to starboard. The sailing analogy is useful - I think it must be the list that causes the problem.

In that case your tiller could be off centre so that under power it counteracts the propwash

[mross]

At certain revs I have to hold the tiller to port to make the boat run true. At high revs I have to hold it to starboard.  With a little fettling I can find an RPM at which almost zero effort on the tiller is required.  This gives me about 3mph so is a nice, relaxed pace.

[billh]

7 hours ago, X Alan W said:

I have to admit it's some years since I boated in a deep drafted boat so perhaps the bridge 'ole' c**p has built up or differs in composition so a float through in neutral may be a better idea (Horses for courses)

Yes, if you use a horse, there will be no problem at all with bridge hole debris on the prop.

I usually "chuck back" after the bridge hole unless the boat has come to a dead stand before it's got through. Reverse any time before that can lead to a disaster, as Alan mentioned. Places like the Macc Canal in autumn  requires leaves to be ejected after every bridge.

[zenataomm]

6 hours ago, Stedman II said:

Perhaps I should not have said 'leave the tiller alone'. What I meant was 'keep hold of the tiller, but don't move it'. The tiller remains dead centre, the prop is not turning, but the boat veers to starboard. The sailing analogy is useful - I think it must be the list that causes the problem.

It's only right!

[zenataomm]

1 hour ago, billh said:

Yes, if you use a horse, there will be no problem at all with bridge hole debris on the prop.

I usually "chuck back" after the bridge hole unless the boat has come to a dead stand before it's got through. Reverse any time before that can lead to a disaster, as Alan mentioned. Places like the Macc Canal in autumn  requires leaves to be ejected after every bridge.

An old boatman taught me to accelerate into bridge holes and as the engine 'ole bulkhead approaches throttle right back and disengage drive.

Your wash overtakes you and then being funnelled into the narrows it lifts the blades over any rubbish and you drift through,  should you still bottom out on dumped treasure then your butty gives you a smart shove up the proverbial and pushes you through.

I still do it now as my current boat draws nearly 3 feet at the rudder and 2 feet at the stem. No butty now but I often wobble through.

[Iain_S]

10 hours ago, Stedman II said:

Perhaps I should not have said 'leave the tiller alone'. What I meant was 'keep hold of the tiller, but don't move it'. The tiller remains dead centre, the prop is not turning, but the boat veers to starboard. The sailing analogy is useful - I think it must be the list that causes the problem.

With a list to port, there will be a tendency for the boat to turn to port under power, due to the prop thrust being displaced to starboard of the centre of buoyancy. This is most likely automatically and unconsciously corrected by the steerer.  With a right hand propeller, any prop walk will work in the same direction. When the power comes off, both these forces are much reduced, but the rudder is still applying the counteracting turning force to starboard.