Seeking steering response and stability

I have a 1982 Marine trader Double cabin 34. I come from the sailing world where I had 7 sailboats over 45 years. All had better directional stability and steering response than my new to me trawler. Somehow -someway the trawler has 6 turns on both steering wheels lock to lock! My last sailboat and most of them had 3 turns lock to lock. In other words, half the turning at the wheel produced an equal turn angle of the rudder. The trawler has newer seastar cylinder and helm pumps. The torque effort at the wheels (24inch diameters) is minimal--can easily turn wheels with one finger. Also the previous owner had the aft end of the rudder extended 3 inches. Boat has a large flybridge enclosure that has a lot of extra windage which a gust of wind knocks off course easily. I was wondering if I could improve things by simply moving the pin connection on the steering ram towards the rudder post as much as the geometry situation allows???? My friend has a Prarie 29 with the same hydraulic steering set up and his lock to lock is only 4 turns-not 6 turns like mine. Comments please>

mine is 4 1/4 or 4 1/2 lock to lock but it is a vetus system

You could try moving the pin - if it doesn't work or you don't like it, move it back?

Low fluid or air in the system ?

Is there a small knob below the shaft on the wheel? If so, tightening it will reduce the number of turns.

What exactly is wrong with 6 turns lock to lock? Pretty much every power boat I've ever owned with hydraulic steering has had the same 2 1/2 -3 turns from amidships to hardover. The steering underway is fine and I've never had any issues docking with a single engine boat ,much less a twin engine.
A sailboat needs a quick response steering system for all of the course changing it does while under sail. A powerboat doesn't. Plus if you change your steering ratio, your autopilot steering characteristics will change ,too.
I would advocate for leaving the system as it was designed.

I have 7 turns lock to lock on my trawler, so usually use the autopilot pump for large changes in rudder angle. Moving the steering cylinder closer to the rudder shaft on the rudder arm will reduce the number of turns from lock to lock. Make sure you have the clearance first as the cylinder rod may hit the rudder shaft. As far as directional stability and rudder response, most sailboats have bigger keels and rudders. Many sailboats have foil rudder. These pull the boat to one side or the other with water flowing over the rudder. A power boat rudder works by pushing the stern over with prop wash. The slower you go, the less effect a power boat rudder has. I find it easier to run with the autopilot most of the time when weather or sea conditions are challenging as the pump can turn the rudder faster than I can and the computer generally will steer a straighter line.

Ted

O C Diver said:

Make sure you have the clearance first as the cylinder rod may hit the rudder shaft.

Ted

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I'm not visualizing what you're trying to say. The cylinder rod hit the rudder shaft?
The whole geometry of the system will be out if the steering ram is simply moved closer to the shaft. The mounting end of the cylinder would probably need to be moved by the same amount so as to keep it symmetric. He would have to make sure the steering cylinder wouldn't become the rudder stop. That's a good way to ruin a steering cylinder

boomerang said:

I'm not visualizing what you're trying to say. The cylinder rod hit the rudder shaft?
The whole geometry of the system will be out if the steering ram is simply moved closer to the shaft. The mounting end of the cylinder would probably need to be moved by the same amount so as to keep it symmetric. He would have to make sure the steering cylinder wouldn't become the rudder stop. That's a good way to ruin a steering cylinder

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It all depends on how great an angle the rudder turns. My rudder can swing 45 degrees. As the rudder angle increases (moves away from center), the attachment point brings the cylinder rod closer to the rudder shaft. Visualize the rudder tuned 90 degrees. The cylinder rod would hit the rudder shaft long before it got there. The further out on the rudder arm the cylinder rod is attached, the greater the rudder angle you can have before the rod hits the shaft.

Ted

In Manual Hydraulic Steering Systems like Sea Star, Hynautic, Wagner, etc the number of turns are the result of how much hydraulic fluid is pumped per turn into the size of the cylinder.

Higher capacity Helm Pump = fewer turns
Smaller diameter cylinder = fewer turns

As these are manual systems any change (helm or ram) will change the amount of force needed to turn the wheel (operate the pump)

Moving the pin connection on the steering ram towards the rudder post will increase the speed of the rudder response, but will not change the 6 turns unless you start hitting stops.

If you have an electric pump operating your auto pilot changing the helm pump will not effect the A/P at all.

The small knob hmason mentions is found on Sea Star Capilano systems, typically found on larger boats.

Sea Star Standard Helms are available in 3 displacements, each will give a particular size diameter ram a different lock to lock ratio. More displacement will reduce turns. You can change just 1 helm and leave the other installed, they will have different turns but the system won't care



Standard Helm • Available in 1.7, 2.0 and 2.4 cubic inch displacements

SeaStar Solutions

geoleo said:

I was wondering if I could improve things by simply moving the pin connection on the steering ram towards the rudder post as much as the geometry situation allows????>

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I had the same issue. 6 turns lock to lock. A bad day on the water with nasty following seas requiring constant turning of the wheel to stay on course and avoid broaching convinced me I wanted less lock to lock.


Have an older Australian Hydrive unit that has no adjustment capability to do this but the Hydrive US rep suggested moving the end of the ram half way in on the arm toward the rudder post.



This I did. Had to drill a new hole in the arm and slightly reposition the ram's base.


Very happy with the result. A little over 4 turns now. Rep said steering might get stiffer, but haven't noticed such.

I set mine up for 40deg of rudder angle each way and got a donated rudder cylinder off a large yacht. Result is 6.5turns lock to lock. I wish it was less. When manuevering sometimes I need to go from one lock to the other it it takes a lot of cranking.

Steering effort is a non issue.

My proposed fix is to go to a smaller displacement cylinder. Maybe get to four turns or so. Understand that I will have to re-tune the AP afterward. So far has not gotten to the top of my list. Other than close maneuvering, steering and AP are fine.

Speed knob helped a good bit.

I have 3 1/2 turns lock to lock. I adjusted the knob mentioned all the way in. Still one finger effort.

Ski: Try one of those suicide knobs, you might like it.

Well I looked at the tiller arm/hydraulic ram arrangement. I didn't measure the pin/post distance but it looks to be 8-9 inches, The tiller also has a 'stiffening ridge' down the middle on top . A new pin location inward would probably involve grinding this flat and weakening the tiller. I will look for the adjustment knob. The ram looks nice and hefty so maybe it is too large and part of the problem. The boat is too short to carry the extra large flybridge enclosure easily. I will probably have to wait till yard time and fishtail the rudder. Was thinking a 4 inch long X 1 inch wedge each side. Guesswork!

I had a steering knob on a previous center console, when docking and turning the engine a lot and quickly the knob was all I ever used. Really made it easy to turn the wheel.

Oh yes- Suicide knobs! Not so good on my boat as both wheels are vertical but Im going to include them in the 'mix'.

dwhatty said:

I had the same issue. 6 turns lock to lock. A bad day on the water with nasty following seas requiring constant turning of the wheel to stay on course and avoid broaching convinced me I wanted less lock to lock.


Have an older Australian Hydrive unit that has no adjustment capability to do this but the Hydrive US rep suggested moving the end of the ram half way in on the arm toward the rudder post.



This I did. Had to drill a new hole in the arm and slightly reposition the ram's base.


Very happy with the result. A little over 4 turns now. Rep said steering might get stiffer, but haven't noticed such.

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Hi Dave do you remember what size drill you used as I will try this on Friday its been driving me mad Thanks in advance

My steering is twice as fast (3 turns) and I wouldn’t want any less.
But it’s more than twice as effective because my swings a total of 90 degrees.

bayview said:

Ski: Try one of those suicide knobs, you might like it.

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I think Ski has one. He refers to speed knob,I'm assuming thats the same thing. I like the Tractor supply ones over the Edson ones. Larger knob.

This thread is interesting. I would like to have fewer turns lock to lock. My steering is great most of the time, but for close maneuvering it would be nice to be able to turn rubber with fewer turns of the wheel.

I need to check, but I think my AP has its own arm and is not connected to the steering hydraulics (I know nothing about my steering system). If I could move the arm on my steering piston to get more response, I would be interested.

I just went thru the catalogs that came with the boat. Found that the Ram cylinder was replaced with a Sea Star HC-314-3 2 years ago. The install catalog says a 6inch pin to rudder post is required. It has a 7 inch travel and a 10.2 Cubic inch capacity. Im not sure but distance looks longer than 6 in. I will measure it Thursday when I go to the boaty!. The helm pumps are Sea Star 7.1 models.

The tiller arm is loaded athwartships, not up and down, unless the cylinder is badly aligned. Shortening a central rib to the new hole location will not make it weaker than it was (unless you decide to move it back to the old location).

gaston said:

Hi Dave do you remember what size drill you used as I will try this on Friday its been driving me mad Thanks in advance

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Measure the diameter of the clevis pin and use a drill bit a hair larger?

dwhatty said:

Measure the diameter of the clevis pin and use a drill bit a hair larger?

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Thanks


Boat is 60km away was just planning what to take with me to do the refit

gaston said:

Thanks


Boat is 60km away was just planning what to take with me to do the refit

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Take lots of drill bits.

ok

Take some cutting lubricant. Nothing shortens the life of a drill bit like getting overheated. A little lubricant goes a long way to keeping the bit sharp and getting our hole drilled quickly.

Remember if the rudder pivots more than 35deg or 40 deg is is a brake , not a rudder.

Our boat was designed by 2 ex sailors so likely the reason for the large rudder and 3 turns stop to stop. I like it a lot!