Reducing hydraulic steering gear-ratio ?

We're new to hydraulic steering and are starting to get used to the lack of feedback from the wheel.

What we are not getting used to is the destroyer wheel with five turn locks to lock. When maneuvering in tight spaces at low speeds it is really awkward to try to rapidly move the rudder without basically spinning the wheel with the danger of slamming into the stops in either direction.

Is there a way to change the gearing in typical hydraulic steering systems ?

Thanks.

5 turns lock to lock is about normal. Some around 4, mine is 6.6 and not happy about that. I may change things to get more like 4.

But if set up right, there is nothing wrong with hitting the stops. System should be set up so it does not hit any mechanical stops in the rudder hardware, but the rudder cylinder simply bottoms out. You can bump into the cylinder bottoms all day long, no harm.

I put a speed knob on, it helps some when maneuvering.

To change ratio, you need either a rudder cylinder with smaller piston diameter (less cubic inch for full stroke) or a helm cylinder with more cu in per rev.

Do you have an autopilot? Many autopilots can move the rudder to port or starboard by pushing one of 2 arrow buttons. The autopilot pump will generally move the rudder faster than you can spin the wheel. Plus, the pilot has rudder feedback that tells the control box when you reach the preset rudder angle limit and stops the pump.

For docking my single screw boat, nothing beats pressing the button or moving the jog lever for charging rudder angle.

Ted

I use a jog lever at each steering station that operates the hydraulic pump. I rarely touch the wheel. Only a few seconds from lock to lock. Nice when docking. I have a switch. Either the pump is controlled by the autopilot or the jog lever.

Thanks everybody. We have a classic Cetec/Benmar Compucourse which we intend to keep just because it IS such a classic. When it is powered on it has 'auto' or 'power' steer (or words to that effect) which is probably exactly what you are talking about. It probably has 20 buttons on the control panel. I think the manual was printed using Wordstar and a dot-matrix printer and it assumes you know what the terms mean

Now we know what to try out !



-Sven

I noticed last week that my helm has an adjustment knob under the destroyer wheel hub labeled “more turns <-> less turns”.

I had assumed it was just a tension adjustment , have not tried it. Possibly adjusting fluid volume to change steering ratio?

If so it’s clever - my boats a 1978 Taiwan trawler

I have one also. It allows you to increase or decrease turns lock to lock. It also changes effort.

I want to say it goes from around two to five. Working on it now, tracing a tiny leak.

I have never docked with autopilot. Never even thought of it. Since I am a single screw I always go really slow and have two plans, and only needed three once. May try it though.

My OA40 with Capilano steering has the "more turns/less turns knob as well. It indeed adjusts the number of turns of the wheel from lock to lock. Mine had no noticeable effect on the effort.


When I first got the boat the lower helm was around five turns and the upper less than four. I dialed in the steering to four turns each by hopping back and forth between the upper and lower helms a half dozen times, adjusting the knob and turning the wheel lock to lock a few times until they matched. I was told that too few turns is hard on the hydraulics and decided on four turns as it's easy to remember for finding the center rudder position from full lock.

I almost never use the helm when docking so I never thought about using the autopilot to steer. I almost always use the autopilot when we are away from the dock so I have never had a problem with the number of turns at the helm.

Comodave said:

I almost never use the helm when docking

Click to expand...

Twin screws I assume, or do you use prop-walk and rudder kick to do the last few maneuvers into a slip ?



-Sven

Yes I do have twins. I also added a stern thruster since I drive from the flybridge and by the time I get past our dog and down off the bridge the stern has usually drifted off the dock. With the thruster and a remote it is simple to bring it back. I found that I was rushing to get down and after almost falling several times I decided there had to be a better way. The thruster allows me to carefully get down from the bridge.

Hydraulic steering systems are mechanical in that human power ends up turning the rudder.

Less turns = More force to turn the wheel
More turns = Less force to turn the wheel

same rules as a block and tackle, more parts = less force but more rope and tackle

The Capilano System is the only mechanical Hydraulic system I am aware of with the variable ratio knob.

You can change the ratio of other systems by either installing a smaller diameter steering cylinder which will need less volume of oil and therefore react faster to the oil coming from the helm pump,
or
installing a higher volume helm pump which will send more oil per turn to the steering cylinder making it react faster

For example this combination BA125-7 cylinder is 1-1/4" diameter with Sea Star I helm, 4 turns

DESCRIPTIONQTY. REQ.MODELPART NO.4 Turns Lock to LockCylinder1BA125-7ATMHC5312Helm1SeaStar I–Standard *HH5271

and this combination:

DESCRIPTIONQTY. REQ.MODELPART NO.6 Turns Lock to LockCylinder1BA150-7ATMHC5314Helm1SeaStar I–Standard *HH5271

With the same helm but a BA150 - 7 cylinder, 1-1/2" in diameter is 6 turns, less force at the wheel, but more turns and more power at the cylinder.

SeaStar Solutions

You could also move the pin on the tiller arm closer to the rudder shaft which will reduce the lever advantage, will not change the ratio, but will make the rudder turn faster per turn but with more force necessary at the wheel.

Capilano Helm:

I also have an adjusting knob. I have mine set to the minimum turns....3 1/4 lock to lock.
Make for easy handling.

Many AP have a rudder position indicator.

Having the AP on but not steering usually allows this indicator to function.

It is a great docking help to know the rudder position at a glance.

Kobelt 7003, 7004, 7005, 7012 and 7031 helmpumps also have an adjustment screw

I have a 2 foot destroyer type helm but, want to switch to change it to a wooden spoked helm wheel. Some of the ones on eBay.... I question the quality. Anyone have a wooden helm wanting to swap it for a destroyer type helm or perhaps recommend a brand?
Lock to lock...... about 5 1/2 turns
Docking with autopilot.... hmmm.... that just might be exciting.

TEASE: I search the auto pilot menu and cannot find the command, "Dock the boat while I handle the lines."
LOL