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Steering Link

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Nautiduck
Master Marine Consultant

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USA
3704 Posts

Initially Posted - 10/27/2007 : 12:41:04

OK, one of my winter projects is to do a rudder-outboard link. I will, of course, study the ones that have already been done beginning with the classic Arlyn Soft Link to the more recent hard links by Paul and Steve. To be honest, all of these solutions just seem overly complex to me. That is not a criticism, just an observation. It may be that my quest will prove fruitless and I will return to the techniques of those who have gone before me.

So, as I begin my project, would someone please tell me why the proposal of simply attaching a rod from point "A" to point "B" would not work?? The rod would have flexible, rotating, quick-release connectors at each end. Such a rod is available (Panther or Stearns brands) or can be easily assembled using the supplier Steve found.

When I look at outboard-to-outboard connections (very common with fishing boats using kickers) they are ALWAYS connected close to the transom and yet all the C250 solutions I see use the trailing edges of the rudder and OB. Why is that?

What am I not seeing??

We cannot direct the winds but we can adjust our sails.

Edited by - Nautiduck on 10/27/2007 12:44:41

Arlyn Stewart
Master Marine Consultant

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2980 Posts

Response Posted - 10/27/2007 : 13:21:47

Hey Randy,

I look forward to following this quest because it of course was one I entertained many years ago.

Part of my education was related to design, form and function and all between.

Start with a purpose statement and then a prioritized goal list with a line between the must and the wants.

I've shared this several times, but will remind that a must on my list was compensation for the limited starboard turn of my motor. This might have been done with a telescoping tubular link with an internal spring... but I didn't get that far because simplicity led to the soft link.

Looking forward to tracking your thoughts...

Edited by - on

delliottg
Former Mainsheet C250 Tech Editor

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4479 Posts

Response Posted - 10/27/2007 : 14:17:09

Randy,
In my case it was the different turning radii of the engine & rudder. In order to make them turn at the same rate, I had to extend the rudder out to meet up with the outboard's attachment point. Plus there's torque, it takes more effort to move the tiller or wheel when it's attached close in like you're proposing, than if they're attached further out. When they're further out, you have a longer moment arm, and your turning effort is less, but you have to turn further (see below). However, that may not be such an issue with a wheel as it is with a tiller. If the wheel already creates a fair amount of torque at the pintles, you may well be able to fairly easily move the engine by sharing the torque with an arm. The power boats you see with this arrangement are probably using hydraulics to move everything. In my case, I chose to move the attachment points out so it was easier to turn the entire affair. You don't want to be in a situation where it's difficult to move the engine/rudder combo because you're tired, or one of your kids has to do it because you're hurt or something.

Another consideration is how far you need to turn. The tiller can only swing through about 90°, and my engine maybe 75°. There's no point in constructing a connection that allows you to swing the entire 90°, because you can't go that far anyway, so I made mine so that it only swings about 90% of the engine's full swing. This becomes evident when you straighten out the connecting rod (all the way to port with the tiller on a starboard turn on mine), towards the last few degrees, the engine is barely moving, and as the rod goes "straight", it's not moving at all. Then you have to worry about going "over center" (Steve had this problem & had to modify his rig, I learned from his lesson & adjusted mine with clamps until the problem went away. If you go over center, you lock the rod (like bending your knee backwards), and you can't turn it back till you pop it back out. Allow for this in your design, or someday when you're not paying attention, it'll happen, probably at the worst time (lots of peanut gallery to watch you run in circles till you hit something).

Edited by - on

Steve Blackburn
Master Marine Consultant

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Canada
1091 Posts

Response Posted - 10/27/2007 : 15:27:06

I know you don't like the design of having that extention to the rudder (the arm). The reason for this is leverage. The longer the arm the less amount of force is required. However as stated in my previous posts, I believe this arm does not need to be so far out.

Make sure your link attachement points are of of equal lengths from the engine and rudder pivot points (yellow line). Red line being the link.

AS shown by the pink line I could have moved the link towards the boat making it a more elegant design. Notice that my link is not parallel with the boat but rather with the engine and rudder pivot points.

David's suggestion on using clamps in the beginning to test things out is excellent. It's not rocket science though, mine worked almost on the first time to the exception of 1 minor adjustment to get rid of geometrical lock.

You can go a long way by simulating a full port and starboard turn with a tape measurer. Turn engine and rudder full port and measure. Do the same on starboard and measure again. You'll start having a good idea where your attachement points should be. The most critical part of this modification is piercing the engine cowl base to bolt on it's attachement bracket. The rest you can redo multiple times without any adverse effects except to your wallet.

One thing I can tell you Randy is that this is a really worthwhile mod as it give you a very increased level of control and turn radius on the boat. A higher degree of precision. This is important when dealing in close quarters and very helpful when loading the boat onto the trailer (as I pilot the boat all the way into the trailer because I can with this mod). People who say they don't need this usualy have plenty of room and permenant slips. I can easily turn the boat on its central axis 360 degrees when giving it a little (very minor) throttle.

Randy what kind of rudder do you have? Is that an IDA rudder?

Edited by - Steve Blackburn on 10/27/2007 15:48:47

britinusa
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5404 Posts

Response Posted - 10/27/2007 : 19:12:09

David, just purchased the materials to make your version of the tough link.
so far.
.. 4' of 3/4" angle aluminum
.. 4' of 3/4" square aluminum tube
.. 4 1/4" internal diameter bronze bushings
.. 2 larger bronze bushings that the 1/4" inch bushings fit.
.. 1 1/4" stainless steel bolt and nylock nut.
.. 1 1/4" 1.5" stainless spring loaded clevis pin.
All from ACE hardware.

Steve, I agree, the leverage is a must, besides, there is a handy dandy flange on the stern quarter of the engine body to connect to. I'm expecting to have to remove the spring clevis pin before raising the engine. I may have to change the clevis pin concept so that it's easy to raise the engine without having to lean over to pull the pin (it'll be on a lanyard so easy to pull out, but putting it back in may not be so easy.

I hope to get it installed before we go off to the Catalina Rendezvous on the 9th.

Paul.

Edited by - britinusa on 10/28/2007 07:04:12

Nautiduck
Master Marine Consultant

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USA
3704 Posts

Response Posted - 10/27/2007 : 20:12:30

Thank you all, this is the sort of information I need. Keep it coming.

Steve, I believe my rudder is the stock Catalina rudder.

All, point well taken about leverage and equi-distance from pivot points.

Arlyn, my design goals are:

-simple design that looks like it might have come with the boat.
-reliable and robust.
-no need to remove or move anything when tilting OB up or down (probably the toughest challenge and likely not do-able).
-stainless steel components.

I am trying to think "outside the box" on this but still pay attention to what has worked for others. For instance I am researching gas spring struts to accomplish what bungee does in the soft link. A stainless steel gas spring with sufficient travel and power can be had for about $50. Couple that with a stainless wire connection between the OB and rudder and you have a mechanized version of the soft link. And, of course, I am looking at hard links as described in my initial post.

Ultimately, it is all about minimizing those moments at the dock when I pray no one is watching.

Edited by - Nautiduck on 10/27/2007 20:16:32

Arlyn Stewart
Master Marine Consultant

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2980 Posts

Response Posted - 10/27/2007 : 20:42:58

Not sure this is a consideration or not... if motoring at cruising speed around 5 kts, a link is not desirable. Steerage is better under rudder only.

Edited by - on

delliottg
Former Mainsheet C250 Tech Editor

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Response Posted - 10/27/2007 : 20:50:04

Paul,
Sounds like you're well on your way, I used 1/2" dowels to fill the square aluminum stock with. This might be overkill, but I wanted to be sure that the aluminum wouldn't get bent by the torque loading. I filled each tube with epoxy to fill the voids between the dowel & aluminum so that they were basically solid. If you do this, be aware that the dowels will want to float in the liquid epoxy, so you need to tape them down or something to keep them from bobbing up inside the tubes. I used epoxy putty to bond the bushings inside the tubes by tamping it down with a plastic dowel (from a beam compass). Then cut the wooden dowel to fit with about 1/2" of clearance at the other end so I could fill that with epoxy putty to seal the end.

I used 1/2" clevis pins instead of 1/4", I felt that the torque could possibly bend the smaller pins, but almost certainly wouldn't bend the 1/2" ones. However, these are also the things I'm rethinking, they're kind of a pain to put in and out, and you definitely have to remove them to tilt the engine. W/o some sort of U-joint similar to an EZ Steer, I don't see a way to get around having to remove them. I made a storage hole for a third spring clip in case I lost one, which has already happened once. The pin is heavy enough to just stay inside the bushings, so it wasn't a big deal, but I've replaced the one I lost.

Not to beat a dead horse, but make sure you allow for geometric lock or going over center, your link must not allow you to get into this position.

Edit: just had a thought about something that'll probably occur to you at some point. That is trying to compensate for the off center thrust from our outboards. I considered this for a while, discussed it a bit in the forum, and then decided to ignore it. I lined up the engine & tiller pointing straight back for my center position and just left it there. I'd considered angling the engine a bit to port (so it'd push the bow to starboard) to compensate, but in the months since I've used it, I've never noticed any problems with the straight ahead engine & tiller position.

Edited by - delliottg on 10/27/2007 20:56:34

Steve Blackburn
Master Marine Consultant

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Canada
1091 Posts

Response Posted - 10/27/2007 : 22:57:03

Arlyn: You're right. At higher speeds steering with the engine the steering is a little too "nervous" (but maybe that's just with a tiller?) If I would let go the tiller at 5knts with the engine on it would most probably steer istelf to a full turn and give us the ride of our lives. Once out in the open, I would rather have my engine straight all the time. Only 1 problem is that when you have a link, it is prefereable to loosen the engines friction nut so the engine turns more freely. So when unlink, I need to figure out how to fix the engine straight ahead.

Paul & David: I will be changing my link to a square aluminum tube as David has for next season. Although I think the round tubing is more esthetic, David's implementation is stronger and I really like the ability to put bushings in there. David, how do you disconnect the link, have you devised a quick disconnect system?

Randy: I agree that lifting the engine without the need to disconnect would be ideal. However I have revised my design and thought hard on how this could be accomplished to no avail. Just keep in mind that rather than focus on this issue, a quick disconnect would compensate.

I believe that for these following reasons, keeping the engine linked while in the upward position is not a good idea:

1. Quick disconnect. If you are lifting the engine anyways you're back there and a quick disconnect is a 3 second job

2. I wanted a smooth unlinked rudder. Easy to steer. But that is probably an issue for Tiller only.

3. The rudder's turn radius is greater than that of the engine. The engine will limit the rudder to about 45 degrees full port or starboard.

Edited by - Steve Blackburn on 10/27/2007 23:13:34

Nautiduck
Master Marine Consultant

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Response Posted - 10/28/2007 : 00:24:34

Agreed it is best to disconnect the OB and rudder once underway. The connection is for slow maneuvering situations. A quick disconnect is very likely the best solution.

Edited by - on

Steve Blackburn
Master Marine Consultant

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1091 Posts

Response Posted - 10/28/2007 : 00:57:25

After you're done with your new link, I'm pretty confident we can figure out how to do your remote throttle/shifter.

Edited by - on

Arlyn Stewart
Master Marine Consultant

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USA
2980 Posts

Response Posted - 10/28/2007 : 06:48:46

There is no turning lock on the pre 2001 Honda motors independent of the friction adjuster and it is too difficult to consider as a centering lock.

This means that for that motor, when disconnecting for cruising, one of two situations apply.

<ol type="1"><li>The friction will need adjusted snug enough to hold the motor centered but loose enough to allow the motor to turn. I tried this but found it not ideal because the friction will of necessity require a good bit more effort when steering.</li><li>When disconnecting the steering arm from the rudder, the arm must then be connected to a fixed point providing the distance needed.</li></ol id="1">

This was also another consideration when the soft link was designed. It was very easy to connect the motor/rudder line to a loop of line around the upper pintel to hold the motor straight when cruising.

I expect the same line loop might work with a hard link or a hard arm positioned so that the link pivots and connects.

Edited by - Arlyn Stewart on 10/28/2007 06:52:37

britinusa
Web Editor

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Response Posted - 10/28/2007 : 07:18:21

Correction: it's 3/4" tubing.

Thanks for the tip about the dowel in the tubing! Good idea.

The bronze bushings from ACE fit very nicely within each other, so the rudder end will be very smooth. And I had guessed you also used the 'putty' to keep the bushings in place. I'll try to draw a nice pic of the bushings.

<center>

</center>
I'm also trying to figure out the connection to my Tohatsu 9.8. looking towards a plate to be bolted to the back of the engine where my tough link connects right now. That will spread the load rather than place it all on a single point of contact.

Agreed, need to disconnect easily (but deliberately!) I may have to ream the bushing at the engine end.
Of course, what would be really neat would be a pin on a leaf spring. Then it would be easy to have a line to the pin, pull it on it=disconnected.

It's the reconnection that is awkward!

Did you put any 'packing' between the rudder pintle plate and the tube to prevent disimilar corrosion?

Paul

Edited by - britinusa on 10/28/2007 08:05:45

delliottg
Former Mainsheet C250 Tech Editor

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USA
4479 Posts

Response Posted - 11/19/2007 : 22:23:31

Randy,
How's your link coming?

Edited by - on

Nautiduck
Master Marine Consultant

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USA
3704 Posts

Response Posted - 11/19/2007 : 23:58:10

All components except one are here. Minimalistic. All Stainless. All off-the-shelf industrial components with a couple of little mods. If this works it will be from what I have learned on this forum and I will have walked in the footsteps of those who went before me.

Edited by - on

Second Wind53
1st Mate

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Canada
45 Posts

Response Posted - 11/20/2007 : 10:59:23

Just a thought on the hard link design. Would it be possible to have the link bar telescopic so the conection pin would be in the middle and both ends stay in place on rudder & motor. Certainly the connections would have to be universals and some sort of bushings to reduce friction in the telescopic parts.

I need to make a new bracket for the remote connections on my Nissan 8hp because at this point it will not turn to starboard at all.

It's always been centered with the friction screw tight but as everyone knows here it makes for big problems in reverse. Going forward the rudder seems to work but in reverse I'm in trouble.

Keep up the good work as I need this issue solved like most of us out there.

Peter

Edited by - on

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