VULNERABLE STEERING SYSTEM

[Minggat]

A few years ago I discovered a vulnerability in my steering system. I am getting ready for another long passage and would really like to see if anyone else has dealt with this.

Boat is Islander 36. Skeg hung rudder.

The Edson steering system is very common, but the skeg hung rudder makes it more vulnerable than a balanced rudder.

2008-
Inspected all before leaving So Cal for Baja. All good.

2012-
Inspected all before leaving Mexico for Hawaii. All good.

On that crossing, I had the rudder centered and wheel brake locked so the Hydrovane could do it's job. Several times we got slapped on the beam, which knocked the rudder off center. We learned to watch for that.

2013-
While setting sail for Maui from Honolulu, steering broke. Got back in and found that a cable had parted. I had 2 new sets made up. Installed one set and made our way to Maui.

One a mooring in Lahina, the swells on the beam were bad for many days. I didn't know that it was taxing my new cables until I went move the boat and one of the new cables broke. With that one cable gone, the rudder was swinging freely when the swells came back. It was slamming against the stops and making the boat shudder. I deployed the emergency tiller, which of course was swinging with power, back and forth across the cockpit until I got my big bungee cord out and lashed the tiller centered with it. The bungee cord was to dampen the shock and try to keep the rudder centered. It didn't work perfectly. Too much power to try to control. That power is the same stuff that took out my new cable.


2021-
Plans to set off of the South Pacific.
In an effort to remove the stress from the cables, I now have a rudder post lock that I can make solid, or give some dampening to try and minimize shock.


I would rather have a rudder lock that will let me catch the trailing edge of the rudder, but it would have to be something I could deploy of release easily from the cockpit.


Does anybody have a similar scenario and a good resolve?

[coopec43]

I don't know why your steering cable would break because it would be less that 2 meters long?

I presume your cables are SS. What size diameter?

Here is the Edson document for chain and wire steering.

https://edsonmarine.com/content/EB381SteeringGuide.pdf

What diameter sheave have you? Apparently for SS cable they should not be less that 7 inches in diameter otherwise the strands will break.

Just looking at the diagram there would be a lot of load on the unbalanced rudder.

[Minggat]

WOW coopec43 ! I was thinking I might get nothing back. Great stuff !!


The only question I have the answer for is the material. I'm in Indonesia and the boat is still in Hawaii.


So Yes. SS cables. I don't remember them being as much as 2 meters long. But maybe.


I do thank you for
" Just looking at the diagram there would be a lot of load on the unbalanced rudder."
with the underlined LOT. So pretty much no matter what I do, I have a vulnerable system. Locking the rudder without including the steering system would be the healthiest thing I could do I'm sure. And of course continue to carry spare cables.


So with that "lot of load", I don't get to relax with my post/rudder lock system. Any thoughts about grabbing the rudder trailing edge?

[GILow]

I’m not sure that an unbalanced rudder is the issue here. Plenty of boats with unbalanced rudders sailing around out there. Including mine for 40 years and 40,000 nautical miles.

Sounds more like you’ve got a problem with the setup.

Yes, Coopec notes the sheave diameter, and then there’s the cable gauge, but I’d be looking for evidence of a seized block or slack in the system allowing shock loads to build.

[GILow]

Originally Posted by Minggat

The Edson steering system is very common, but the skeg hung rudder makes it more vulnerable than a balanced rudder.

Actually, that’s completely backwards. The main benefit of skeg/keel hung rudders is they are protected by the skeg.

Balanced rudders are very difficult to create without being more exposed and vulnerable.

[Minggat]

GILow, Watch out. Minggat is 47 now. You might be due. But age doesn't explain the short lived new set. What does explain it is the conditions I was in. I am not likely to ever be in the same conditions again. And I know now how to bring the bow into the swells regardless of wind direction.
But still, getting slapped on the beam while underway, sufficient to knock the rudder off center with the wheel brake engaged (but obviously not tight enough), is an indication that there is some shock loading going on.

[Minggat]

Originally Posted by GILow

Actually, that’s completely backwards. The main benefit of skeg/keel hung rudders is they are protected by the skeg.

Balanced rudders are very difficult to create without being more exposed and vulnerable.

Sorry. Try reading it differently.
the STEERING SYSTEM is more vulnerable. Not the rudder.

[coopec43]

Originally Posted by GILow

Actually, that’s completely backwards. The main benefit of skeg/keel hung rudders is they are protected by the skeg.

Balanced rudders are very difficult to create without being more exposed and vulnerable.

I most certainly won't argue with that!

[coopec43]

Originally Posted by Minggat

Sorry. Try reading it differently.
the STEERING SYSTEM is more vulnerable. Not the rudder.

I see what you are getting at now.

Of course with a balanced rudder the loads on the cable/chain/steering are very much lower.

Looking at your rudder it is quite wide but not all that high. (a low aspect ratio rudder) My logic tells me the loads would be quite high.
Construction and Types of Rudder on Ships


https://marineengineeringonline.com/tag/aspect-ratio/

[slug]

Originally Posted by Minggat

A few years ago I discovered a vulnerability in my steering system. I am getting ready for another long passage and would really like to see if anyone else has dealt with this.

Boat is Islander 36. Skeg hung rudder.

The Edson steering system is very common, but the skeg hung rudder makes it more vulnerable than a balanced rudder.

2008-
Inspected all before leaving So Cal for Baja. All good.

2012-
Inspected all before leaving Mexico for Hawaii. All good.

On that crossing, I had the rudder centered and wheel brake locked so the Hydrovane could do it's job. Several times we got slapped on the beam, which knocked the rudder off center. We learned to watch for that.

2013-
While setting sail for Maui from Honolulu, steering broke. Got back in and found that a cable had parted. I had 2 new sets made up. Installed one set and made our way to Maui.

One a mooring in Lahina, the swells on the beam were bad for many days. I didn't know that it was taxing my new cables until I went move the boat and one of the new cables broke. With that one cable gone, the rudder was swinging freely when the swells came back. It was slamming against the stops and making the boat shudder. I deployed the emergency tiller, which of course was swinging with power, back and forth across the cockpit until I got my big bungee cord out and lashed the tiller centered with it. The bungee cord was to dampen the shock and try to keep the rudder centered. It didn't work perfectly. Too much power to try to control. That power is the same stuff that took out my new cable.


2021-
Plans to set off of the South Pacific.
In an effort to remove the stress from the cables, I now have a rudder post lock that I can make solid, or give some dampening to try and minimize shock.


I would rather have a rudder lock that will let me catch the trailing edge of the rudder, but it would have to be something I could deploy of release easily from the cockpit.




Does anybody have a similar scenario and a good resolve?

The Steering system is one of the most vulnerable , maintenance intensive systems on the boat
It is stressed at sea and at anchor

Twice yearly inspection


Steering cables must be correctly aligned and the cable turning blocks must be correct
No chafe

Grease helps

Get the cable tension correct , slack cables chafe

Remember , the whole system is in action when your auto is running
The emergency tiller is neglected on all boats
Test it out at the dock then consider what it would be like to steer 1000 miles with it

[Minggat]

There was a Kona wind episode at the end of my stay in Maui. I had to use the emergency tiller to cross over to the lee side Lanai for safety. Of course the binnacle in the way didn't make it any easier, but what a bear to steer with the tiller.

[Minggat]

Originally Posted by slug

The Steering system is one of the most vulnerable , maintenance intensive systems on the boat
It is stressed at sea and at anchor

Twice yearly inspection


Steering cables must be correctly aligned and the cable turning blocks must be correct
No chafe

Grease helps

Get the cable tension correct , slack cables chafe

Remember , the whole system is in action when your auto is running
The emergency tiller is neglected on all boats
Test it out at the dock then consider what it would be like to steer 1000 miles with it

Thanks for that.

Funny about the emergency tiller. the first time I was forced to use it, I discovered it was built 90 degrees out. The second was that crossing to Lanai. I have since wondered if it was originally built like that because of the binnacle being in the way.

[slug]

On oceanic, high endurance boats , the emergency tiller socket is mechanically bolted to the rudder stock head . It cant move , jump off or round off the socket , rudder stock

Block and tackle can be used to operate it but the preferred setup is an electric tiller pilot

The common raymarine type

[dfelsent]

I’ve never quite fully trusted the Edson wheel brake alone when the breeze is up or a swell running. I’ve seen too many failures. I tie the wheel then.
There is a ratio of sheave to cable diameter that prevents excessive wear and strand breakage. If you have 5/16” cable and 6” sheaves you will have cable life issues.
Alignment of the sheaves is also important.
The cables and chain are an inspect and maintain item for sure. Excessive tension, inadequate tension, lack of lubrication, or misalignment will lead to failures.
Edson customer support has been very good to me. I suggest emailing them with photos and asking questions!

[Minggat]

Originally Posted by dfelsent

I’ve seen too many failures. Excessive tension, inadequate tension, lack of lubrication, or misalignment will lead to failures.

Edson customer support has been very good to me. I suggest emailing them with photos and asking questions!

So much good input here.

Clearly there are a lot of details that can take these systems out.
I thought I had a reasonably handle on things. Very Glad I asked. Thanks guys.