rudder alignment, starboard turns, search issues

[blue angel]

I have been searching the archives for some time trying to find tips on how to get the rudders and engine aligned on a 26m, and have had much better luck searching google to get to the right spots on this forum than using the powersailor search function.

I also note that many often tell newbies to go search the archives, but it is not that easy to do, so maybe some patience would be in order. again, several times I have found a good thread on google, ON THIS FORUM, but not using the internal search function, recently searching for steering bar 26m and for dingy power options. btw any one have experience with the suzuki 2.5?

on the 26m does the bluewater quick disconnect somehow help one keep the rudders aligned?

also, my boat like to turn to port a lot more than starboard, especially with the engine connected (engine hits the ladder and bar too short), but even disconnected, when bar still too short, and it still happens when sailing with the bar disconnected, so it is not all about prop walk. using google, I found others who had this problem but found no real solution yet. any ideas.

also, on the m, the good news is that is sails great and balanced with main only, better than my older mac or most other boats especially with the bluewater bearing that helps the mast rotatea easier even in light winds, but even the small working jib gives it quite a bit of lee helm, worse when light at the bow, any ideas on that other than just loading the bow heavier?

thanks,

[Duane Dunn, Allegro]

The BWY quick release does make it a lot easier to align the motor to the rudders. It has a threaded ends on the rod that let you adjust it's length to get the motor exactly centered when the rudders are exactly centered.

Of course you have to have the rudders parallel to each other which I think is more adjustable on am M than it is on my X. I seem to recall that back in the aft berth you can adjust the angles of the rudders to each other. There is no such adjustment on my X.

It's not going to stop the rudder from hitting a ladder however. I have that problem when my port rudder is up, in the down position they both are clear. My ladder is outboard of the port rudder, not along side the motor.

[delevi]

Blue,
The search function does leave some things to be desired. As for the BWY disconnect, although it's a great item (I have one too,) it does nothing to align your rudders. The problem with the engine steering bar running out of room is normal on the M. You basically have about 5 degrees more steerage on one side. It' still ample. Your enigne should never hit the ladder. Pull the ladder up and fasten with a small bungee. Going back to the rudders. When you say alignment, are you referring to both rudders running parallel or fore and aft angle? Fore & aft angle is adjusted by the screw on the stopper which hits the rudder bracket. The ruddders should be perpendicular to the water (as perfectly as possible.) As far as being parallel with one another, check carefully. It is a bit deceiving sometimes looking through the water. If they're really out of alighment, the fix is not easy. You would need to remove the rudder linkage bar and bend it. It is very difficult to bend. Some have made mods to replace this bar with an adjustable one. Mine were slightly out of alignment and I ended up bending the bar using a crowbar for leverage. Crude, but it worked. There is no precise method. I got lucky. They're still not perfect but pretty close. If you're within a few degrees, I'd leave it alone. Last but not least, lee helm. That's a stumper. These boats are prone to weather helm, not lee helm. This may be the first time someone has complained about lee helm. This may sound like a stupid question, but was your daggerboard lowered all the way? If so, the next thing to consider is your headsail trim. Perhaps it was overtrimmed. If neither is the culprit, you will need to adjust your rig. To reduce lee helm/induce weather helm and improve pointing, lengthen the forestay by adjusting the turnbuckle. Of course, you will need to adjust the rest of the shrouds to compensate since any change in tesnion of one piece of rigging affects the rest. Don't lengthen too much or you'll have too much weather helm. I'm guessing it's one of the first two things. Lee helm on these boats is almost unheard of. The only time I get it is when tripple reefed, beating upwind in 30 knots+ due to too much jib compared to the tiny (reefed) main. The jib can't be rolled less than half its size in this configuration in order to make any headway upwind through chop. This sounds like nothing you described, however.

Hope this helped. Good luck.

Leon

[Rob S]

I played around with rudder alignment on my X a lot last year. For rudder/motor alignment you might try the following to give you some clues....... try motoring at slowish speeds with both rudders down. It's best to do this on a slackish day directly downwind so wind/hull effects are minimized. Get the boat running straight, when stable pull one rudder up and observe what way the boat turns. Then repeat with the other rudder. You can also try motoring at slow speed with both rudders up then drop them one at a time and observe, though it's more difficult to get the boat stable and straight on engine only. And you can also try using only one rudder at a time. The variations in what you may observe are infinite but they may give clues from which you can make logical deductions..... e.g. for both rudders, boat turns right when each are pulled up. This would mean that the rudders are countering a right turning tendency of the engine, engine pointing too far left, needs to be adjusted to point right a few degrees. On my X that would mean shortening the engine connect bar a few millimetres. But it gets more complicated when the rudders do different things, or one does more than the other. This would suggest the rudders are fighting each other.

I first stated thinking about this after I got a pair of Ida-rudders last year (really good... made a lot of difference). One day I mistakenly accelerated the boat to about 12 knots with the rudders still down. I realized my mistake when I looked down behind the transom. Well, Ida-rudders are a lot more bendy and flexible than stock rudders and I was horrified to see that both rudders were bending inward towards each other to an alarming degree! Well, once I got over the shock of seeing this distortion and once they returned to their normal straight selves, I started thinking about this.

The only way a rudder would bend like this when overloaded would be if it was operating at an angle of attack, but this would cause a turning force and the boat would turn. But the boat was straight! With the rudders bent towards each other they had to be fighting each other........ the starboard rudder commanding a right turn, the port rudder commanding a left turn, net result..... they cancel each other out but just create a lot of extra drag.

It was logical to assume that this would be caused by the rudders having excessive toe-in, i.e leading edges being closer to each other than trailing edges. Well, this was a shock to me because during the winter I had gone to a lot of trouble to make sure the rudders were as PARALLEL to each other as I could get them. I assumed that parallel rudders would not fight each other and drag would be minimized.

I did some searching in this site about rudder alignment. Lots of opinions, nothing conclusive. Most thought parallel was the obvious answer. One or two thought slight toe-in might be better, no one thought toe-out would be good.

Well, after much thought, to me, toe-out does in fact make sense. Think about it.... as the boat moves through the water, at the bow water starts to diverge around the boat, becomes parallel at it's maximum beam point then coverges toward the stern..... nature abhors a vacuum. The rudders are placed in this convergence zone meaning that if they are to be at a zero angle of attack, they each need to be pointed outboard (toe-out) slightly. Of course there is no perfect solution. Convergence will be greatest from the water suface to the draught depth of the boat. At the rudder tips there may be no convergence because the boat has not disturbed the water at that depth. So the ideal rudder might have a little twist to it like an airplane prop. Then again, the perfect twist would be only for one particular speed, as would perfect toe-out, and all of this assumes the boat is not heeling...... who knows what the flow is like with 25- 30 degrees of heel?

Well, I played around with it a lot as per my first paragraph. I eventually got everything so that at about 4 knots, raising each rudder had no effect on turning the boat (took a lot of trial and error to get the engine alligned to have this happen). My rudders have about an inch of toe-out (i.e. distance between leading edges one inch more than distance betwwen trailing edges) and I think that must be close to optimum for sailing fairly flat at about 3 to 4 knots.

If my convergence/toe-in theory is correct, and your engine is aligned and your rudders are perfectly parallel, then the starboard rudder would be commanding a right turn, countered by the port rudder commanding a left turn. With both rudders down and running straight on engine, on raising the starboard rudder the boat will turn left (because port rudder is turning it) and vice-versa for the port rudder. Complicated huh?!

I'm not so much intersted in perfect engine alignment ('cos most of the time with the engine you have the rudders up anyway) as I am with minimizing the drag caused by the rudders fighting each other when sailing, though like I said, who knows what optimum would be at 6 knots, 30 degrees of heel and a bunch of weather helm?!

By the way, the only way I could adjust the toe-in/out is by bending the connecting bar. I used a 3ft ruler, measured the distance between the holes where the rudder pins insert, applied some force, re-measured, more force, measure, force, measure etc. Trial and error. The point of measuring is to see the changes, not go for a particular figure. I bent the bar by wedging it into the square tow bar (ball hook removed) of my truck and putting my weight on it. There are two bend points on the X's bar (don't know what the M's is like). You need to bend/unbend each equally.

[Hardcrab]

Interesting theory.
But my take would be that 90% of the rudders are well under the convergence area as you describe it.
A fully adjustable "tie rod bar" is easy to make from 1/2" SS all-thread and genuine SS ball joint ends.
I'm in the "everything perfectly parallel to the centerline group" of thought.

It required patience and time, but my setup is as I desired it.
With the motor connected to the linkage, the motor up or motor down, the helm does not significantly change while keeping the same heading.
Same thing goes when the motor is disconnected and pinned for straight ahead.
One rudder or two.
I had to think and fiddle around a lot, but my helm remains within 3/4" along the circumference of straight.

Try it to see the differences as mentioned.
Pick a baseline condition, say, motor down and in gear with rudders down.
Go straight as possible in the best conditions.
Place a piece of tape at 12:00 on the wheel once straight ahead on the water is established.
Stop and raise both rudders then go again with the same conditions.
Where is the tape/helm to go straight? Has it moved and in what direction?
Try it with linkage connected then disconnected and pinned.
Then go for an easy sail with the motor raised.
Try one rudder then two.
I'd think if you can get it no change at the helm in any combination, you must be close to the right idea.


In all honesty, those who are not interested in getting the best they can from their limited performance Mac could care less, I'd think.

[Rob S]

Interesting theory.
But my take would be that 90% of the rudders are well under the convergence area as you describe it.
.................I'm in the "everything perfectly parallel to the centerline group" of thought.

Yes, I would be too. But that wouldn't explain why my rudders bent inward when I motored too fast, nor why raising one rudder at a time with everything adjusted the boat carries on in a straight line. After all, if neither rudder is aligned with the boat centerline and there is no "convergence" then raising one would cause an assymetrical condition and the boat would turn?

[Hardcrab]

Rob,
When you said bend, do you mean bending as in a bow an arrow or toe-out/toe-in at the leading edge?

Trying to follow you here,

"If neither rudder is aligned with the boat centerline"------
How do you check/know alignment to centerline, or put another way, what is the physical reference/measuring point?

Yes, raising one rudder would "cause assymetrical condition and the boat would turn", unless the remaining rudder is not, in fact, assymetrical but straight?

Just trying to understand your theory.

A test of your idea could be done with a test rudder made so that no leading surface is forward of the vertical pivot point, unlike what is stock now.
The stock rudder has surface in front of the pivot point to act somewhat like power steering.
Once the leading edge gets on one side or the other of the flow, it tends to use the force generated to decrease further effort in steering.
A rudder made with no "forward overhang" can only "stream" and react with the prevailing flow if it's not connected to any steering linkage.
Sail with the stock rudder connected and the test rudder disconnected and see which way it wants to react to the ambient flows.
Or perhaps underwater rudder mounted telltails of some sort to show flows.

After your trials, do you think any honest performance gains were seen?
My results were slight but positive. My factory bar was measured at 1" longer than my all thread replacement, causing severe (to me) toe-out.

[Trouts Dream]

I would think your rudder were bending due to the influence of the propeller. At 12 knots there is a lot of water being pulled into the prop and then pushed back again. As you say nature doesn't like a vaccuum and since a lot of water is being pushed behind the prop a lot of water flows into the hole the accelerated water leaves. Simply put this explains why every piece of errant rope or twine will get sucked into a propeller within a 3 foot radius. One of Murphys Laws.

[Rob S]

Rob,
When you said bend, do you mean bending as in a bow an arrow or toe-out/toe-in at the leading edge?

"If neither rudder is aligned with the boat centerline"------
How do you check/know alignment to centerline, or put another way, what is the physical reference/measuring point?

After your trials, do you think any honest performance gains were seen?

Bow as in bow and arrow, like a springboard.

Yes, your're right. I can't allign it with the centerline, just measure leading edge to leading edge and trailing edge to trailing edge.

Performance gains..... hard to know in varying conditions. but nothing dramatic. I have a subjective impression that there is less tendency to round up.

[Kelly Hanson East]

Remember you should have your rudders up and stowed above 6 knots - it isnt surprising to me that rudder operation at 12 knots would be funky. Forces are going up as the square of the speed, so you are 4x over the safety margin at this point

[c130king]

I have never noticed a difference in turning capacity between port and starboard.

But I know my motor when hooked to the steering is a little out of alignment with the rudders. And when the motor is disconnected and secured straight it is also out of alignment a little.

But at 6 knots who cares. You can't tell when looking forward only when looking down at the motor and see that it is a couple of degrees off.

More sailing, less worrying.

Cheers,
Jim

[Kelly Hanson East]

I have never noticed a difference in turning capacity between port and starboard.

Rudder travel on "macm" is not symmetric in general, from the boats I have seen.

[BigNige]

I aligned my rudders and motor on the trailer. I fixed the rudders so that they were parallel to the ground. This makes it is easy to judge which way they are pointing. Luckily both rudders were aligned with each other from the factory (it seems this is not always the case!). At the time I didn't attempt to align them with the steering wheel (i.e. wheel at centre lock to lock and rudders pointing directly astern). In fact my boat does turn sharper to starboard than to port but correcting this would require some judicious bending of the steering gear which I would only have attempted if the rudders were pointing in different directions and has proved to be of no significance whatsoever on the water) . I then attached the motor linkage to find that the engine was pointing well off centre. I fitted a longer connecting bolt to the standard engine connector and added a 21 mm spacer to get them all aligned and its been fine ever since.

Except for one problem! The rudder brackets for some inexplicable reason are 6mm wider than the rudders that fit inside them. The manual suggests you tighten the bolt to pinch up this gap but I found they still twisted in the bracket and would clunk when changing direction under way. The cure was to cut some tupperware "washers" about 75mm square and fit these between the rudder and the bracket (1 x 1.5 mm on the side of the adjusting screw and 3 x 1.5 mm on the other side otherwise the screw misses the stop) and then pinch up the bolt. This provided much better support of the rudder headstock in the bracket and has eliminated all the knocking.

[Rob S]

Remember you should have your rudders up and stowed above 6 knots - it isnt surprising to me that rudder operation at 12 knots would be funky. Forces are going up as the square of the speed, so you are 4x over the safety margin at this point

Yes, a bad error on my part. The forces must have been enormous and I'm lucky nothing broke or that I didn't catch any sudden heeling motion. The bow in the rudders had to be seen to be believed..... as if the boat was on stands with two hefty guys pushing with all their strength on the rudders, inward towards each other. I doubt the rudder tips were more than a foot apart. Very alarming to see, and once I'd got over the shock got me thinking, " If I went to such trouble to get the rudders parallel, why did they do that?'

Sorry Trout, it wasn't prop wash/inflow. If you'd have seen it, you would have no doubt.

[Hardcrab]

I believe the turn difference is due to the short push/pull steering tube that exits the hull in the motor well.
On our boat, it can "push" (port turn) further than it can "pull" (stbd turn).
It seems to be limited on the pull stroke by the engine coupling bolt/pin hitting the fiberglas at the exit hole.
It might be improved by re-rigging everything with some new geometry to establish a different "zero", but not worth the effort for me.
In use, I don't seem to notice any problems with the turning difference.