Inboard steering: hard to turn against prop rotation

[1980Coronado]

Re: Inboard steering: hard to turn against prop rotation

Any luck fixing this issue? I have a similar issue with my 1985 Ski Supreme.

No, but I haven't done anything to it yet. I need to start looking for some wedges to bolt onto the rudder, or find a different rudder. Taking the kids tubing is giving me tennis elbow. I keep hearing about these wedges or tabs that can be mounted to the rudder but I haven't been able to find anything on the net.

 

[1980Coronado]

Re: Inboard steering: hard to turn against prop rotation

Mark, I am enjoying this thread...we have a Century at out docks, looks to be about 21 footer & appears to be a fiberglass Coronado. It's dark blue. It used to be one of my favorite boats til I saw, horrors, a stern drive. Century runabouts need inboard drives dammit!

Amen to that! I just love the sound of a big block chevy inboard.

 

[1980Coronado]

Re: Inboard steering: hard to turn against prop rotation

I/O Coronado's are worth much less then an inboard, with a V-drive Coronado worth the most.

Is that because they didn't make vary many, or because they are better in some way? I've never actually seen a V-drive Coronado except in pictures.

 

[1980Coronado]

Re: Inboard steering: hard to turn against prop rotation

Ok.....been conversing with some guys via facebook at Century Boat Club. There could be a couple of things going on here. Someone mentioned that since my boat is the 2nd one made (based on Hull ID) in 1980 after a 4 year layoff from building inboards, it's possible that Century made a mistake with this one. My prop is not offset from the rudder like the older wooden models. The prop and motor are usually set askew to the CL of the boat to offset the tendency for the prop to turn the boat. I haven't been able to locate anyone with a post 1980 Coronado that can check this for me. I'd like to know if in fact mine not being offset is a mistake or intentional. I'm hoping there is someone out there with an 80's Coronado that can check to see if theirs is offset or in-line.

I'm also being led to believe that this is a steering cable issue but I'm still skeptical.

 

[rallyart]

Re: Inboard steering: hard to turn against prop rotation

if, at idle your steering is easy it is not a cable issue. Most inboards are one finger steering all the time. Mine certainly is. A stiff cable is stiff all the time unless you lubricate it.
Many inboards had rudders 'tuned' so that they had a preload to make the steering stiffer at speed. The intention of this was to stop the driver from wandering while going through a ski slalom course. This was done by using water pressure to load the rudder. Some newer rudders include an adjustable tab to accomplish this to the desired degree. If your rudder has this built in you can reduce this preload by shaping the trailing edge of the rudder with a file. If you make an error and remove to much material from one side it can be remedied by removing some from the other side.
Your boat is hard to steer to starboard so the trailing edge of the rudder is hard to push to starboard. You make this easier by filing the starboard edge to 'flatten' it slightly. Instead of an abrupt angle You will wind up with a slight progressive bevel. like sharpening an axe. Try this, if you wish, and if the problem gets worse you can reverse it by doing the same on the port edge. I'm quite sure the problem will not get worse.

 

[1980Coronado]

Re: Inboard steering: hard to turn against prop rotation

if, at idle your steering is easy it is not a cable issue. Most inboards are one finger steering all the time. Mine certainly is. A stiff cable is stiff all the time unless you lubricate it.
Many inboards had rudders 'tuned' so that they had a preload to make the steering stiffer at speed. The intention of this was to stop the driver from wandering while going through a ski slalom course. This was done by using water pressure to load the rudder. Some newer rudders include an adjustable tab to accomplish this to the desired degree. If your rudder has this built in you can reduce this preload by shaping the trailing edge of the rudder with a file. If you make an error and remove to much material from one side it can be remedied by removing some from the other side.
Your boat is hard to steer to starboard so the trailing edge of the rudder is hard to push to starboard. You make this easier by filing the starboard edge to 'flatten' it slightly. Instead of an abrupt angle You will wind up with a slight progressive bevel. like sharpening an axe. Try this, if you wish, and if the problem gets worse you can reverse it by doing the same on the port edge. I'm quite sure the problem will not get worse.

You have to realize this is a 30 year old boat with no power steering. This is not a competition ski boat, it's a 21'-10" great lakes run about that weighs 3600 lbs. It's very old school. I agree with you that it does not seem to be a cable issue, but other Century Coronado and Resorter owners are telling me that it may be the cable in their experience. It's something that I need to now rule out for sure.....but I've never taken a steering assembly apart....and original parts for this boat are going to be a problem to find.

The rudder is very small for a boat this size, and I'm betting there wasn't any tuning involved. Modifying the rudder in the manner you suggest is not something I'm willing to try. Century made hundreds of these starting as wood boats in the 50's continuing thru 1998. They were are a very sought after boat and I can't imagine that they all had steering issues like this from the factory such that the rudders needed to be modified. It has to be something else....like the cable or the offset of the prop.

 

[1980Coronado]

Re: Inboard steering: hard to turn against prop rotation

I've seen the "hard steering" problem in quite a few older inboards when they are at speed. What I found was that when sitting still they turned easily but when the rudder had a load on it the steering became all but impossible to live with. As a suggestion, assuming you have it out of the water use a rope/come along and pull the rudder backward and see if it is still easy to turn. If not, its time to disassemble the rudder and examine the bearing(s) for wear. There is a world of differnce between what it takes to move the rudder when its hanging freely and when it has a real load on it.

It's on a lift right now in the water. Will be pulling it out for the season soon after labor day. I intend to dig into it once I get it out and back home where I can work on it.

Here's what I know or have confirmed:

The older wooden Coronados had an offset of the prop to counter act the torque of the propeller. The stringers were actually twisted intentionally such that the engine, transmission, and prop shaft were not parallel to the keel. The slight angle of the drive resulted in the prop being offset from the rudder by about an 1" +/-. They did this to solve the exact problem I'm having. This is a big problem with people who restore the old wooden boats and don't know about the offset. When they rebuild them they put them straight in-line with the rudder and they have steering problems like I'm experiencing. The steering is hard in the direction of prop rotation and the boat doesn't turn as well in that direction as well. When I give full right rudder at let's say 15 mph, the boat does not respond like it does when I apply full left rudder. It's like the boat doesn't want to turn as well in the one direction, even though the rudder has equal movement in both directions.

There is an example of the lateral offset about halfway down on this page:
http://centuryboatclub.com/mistakes.htm

What I don't know is if my boat should have this same offset, because it does not. I'd really like to see another 80's Coronado to see if it has this offset. It's possible that Century made a mistake when they built this one. They did not make any Inboards at all between 1976 and 1981....a few dealers got enough orders together to get them to produce a few in late 1980 after taking 4 years off. You will not find the Coronado listed in the 1980 catalog, it didn't make it back in until 1981. I know mine is the second one produced that year. I just don't know how likely it is that an error was made. I've been told by others, with fiberglass Resorters (smaller boat but very similar hull) that do have the offset.

Even if I determine an error was made, I'm not sure it can be corrected now.

Now...you mentioned bearings in the rudder. I removed the rudder but did not see any bearings. The brass (probably NIBRAL) rudder is all one piece and has a 1" shaft that inserts thru a fitting in the hull of the same material. It has a packing nut on it just like like the drive shaft. When I reinstalled the rudder I put new Gortex packing in the nut to seal the shaft. I did not see any indication that there were bearings inside the fitting. The fitting was a slip fit to the shaft such that I don't see anyway that there would have been sleeve bearings or bushings inside, but I never specifically looked either. The rudder seems to be riding on the Gortex packing material and I didn't feel any large amount of play in the rudder after installation.

 

[rallyart]

Re: Inboard steering: hard to turn against prop rotation

Coronado, my boat is a Sanger. Mine is a 2006 but they have been around from the '50s and is of fiberglass over wood construction in many parts. It's 21'8" and weighs 3200# with a 16? deadrise at the transom. It's different from yours but other than a deeper V it's not a day and night difference from how it runs in the water.
With regard to offset of the prop or rudder, mine has a left hand prop that is centered in the hull and the driveline is straight. My rudder, however is offset about an inch to starboard from the propshaft. This is different from many current boats. Perhaps that will give you some insight into what might be done. I'm glad you are trying to keep it original. My suggestion was to give you a common method of tuning the steering.
I suspect your boat does not have skegs for tracking. If it does a bent one can dramatically affect the boats steering. Anyway, good luck.

 

[1980Coronado]

Re: Inboard steering: hard to turn against prop rotation

Coronado, my boat is a Sanger. Mine is a 2006 but they have been around from the '50s and is of fiberglass over wood construction in many parts. It's 21'8" and weighs 3200# with a 16? deadrise at the transom. It's different from yours but other than a deeper V it's not a day and night difference from how it runs in the water.
With regard to offset of the prop or rudder, mine has a left hand prop that is centered in the hull and the driveline is straight. My rudder, however is offset about an inch to starboard from the propshaft. This is different from many current boats. Perhaps that will give you some insight into what might be done. I'm glad you are trying to keep it original. My suggestion was to give you a common method of tuning the steering.
I suspect your boat does not have skegs for tracking. If it does a bent one can dramatically affect the boats steering. Anyway, good luck.

I appreciate the replies......Are you sure that the rudder if offset on your boat? Can you see that the rudder is not on the center-line of the boat.....or is it really that the drive is askew (would hardly be noticeable inside the boat) at a slight angle such that the rudder looks offset. I always thought they offset the rudder too, until Frank Miklos from Century Boat Club explained it to me. You are also correct that this boat does not have skegs like the competition ski boats do.

Someone suggested that I put wedges on the rudder....I may try that eventually if I rule out the cable and find out that it was made correctly.

 

[1980Coronado]

Re: Inboard steering: hard to turn against prop rotation

I shouls have said, "Bearing surface" because boat builders used lots of differnt materials. Where the rudder shaft omes through the hull, the sleave it slides into is a bearing surface and under load can bind. I would still test with a lodd against the rudder.

That makes more sense with what I saw when I took it apart. The tube thru the hull is the bearing. It's something else to rule out.

I really think there is something to this lateral offset issue....but I'm hoping it's a cable issue!

 

[rallyart]

Re: Inboard steering: hard to turn against prop rotation

My driveline is centered so you can look straight down the keel past skegs, shaft strut and prop centerline. The rudder itself is offset on Sangers to starboard and it is a left rotation prop. My steering really is one finger at any speed. It's rack and pinion to cable to rudder with no assist on anything. It will run a mile straight without steering input if the water is good.
My older boat is a 1980 Grew, who have closed out a couple times. Finding parts for it and it's 470 Merc is no joy but at some point they are just machines so you can change them if need be.

 

[1980Coronado]

Re: Inboard steering: hard to turn against prop rotation

My driveline is centered so you can look straight down the keel past skegs, shaft strut and prop centerline. The rudder itself is offset on Sangers to starboard and it is a left rotation prop. My steering really is one finger at any speed. It's rack and pinion to cable to rudder with no assist on anything. It will run a mile straight without steering input if the water is good.
My older boat is a 1980 Grew, who have closed out a couple times. Finding parts for it and it's 470 Merc is no joy but at some point they are just machines so you can change them if need be.

Well.....mine is one finger in one direction and you'd better get a hold of it in the other . It does not pull though....it'll run straight just like yours......I have a phone call into Wawasee Boat Company in Syracuse IN. They used to be a large Century dealer back in the day. I'm hoping I can get a chat with a service tech that used to work on these things, if there's one still around there.

last fall it was learning how to replace the drive shaft...this fall it's going to be learning how to disassemble and check a steering system...yee ha.

 

[1980Coronado]

Just looked at it under the dash. Its a rack and pinion design. No place to lubricate it. Looks very easy to remove. I'm thinking the rack and pinion has enough wear in it that its binding under load.

Sent from my BlackBerry 9650 using Tapatalk