Cable Assist Hydraulic Steering Vs Full Hydraulic

[Whiteknuckle]

Just for sake of conversation, please explain to me why the cable assist is considered so inferior to the hydraulic helm. Again, I don't know, but it seems that you are just sending the steering wheel input back to the hydrualic unit in either system. Why would there be any more stress on the cable than usual. They hydraulic cylinders is what hold the drive in place at any speed. There is no more stress on the cable at 80 MPH than 10 MPH is there? I thought the whole key here was to replace the mechanical tiller arm. Please explain.

[Boatally Insane]

Going to full hydraulic would eliminate the play found in the steering cable and the factory valve. Going to a half system would be safer than nothing but still may have some chine walk because of the play.



Doug

[Whiteknuckle]

Ok BI
Again just for conversation, why would it tend to chine walk? Why would the drive move or wobble if it was held steady in place by the hydaulic cylinders? In fact, I'm not convinced that chine walking is a result of steering anyway. Please clarify!

[Boatally Insane]

There could always be other factors causing chine walk such as over-trimming or prop selection just to name a few.

My thoughts would be that the valve on the cable steering isn't as precise as a full hudraulic helm so the outdrive is possibly not held as firmly in place.


Doug

[Falcon]

With "quick" steering inputs the shuttle valve internal ports cannot pass fluid quick enough to the rams causing a fair amount of the load to be transfered through the arm. These small ports (designed for the internal ram) also cause most cable setups to have more wheel effort. Another issue is that any hydraulic systme still has some spring in it (line expansion and air). Under a high sudden side load the cylinders can compress slightly causing some load on the cable/arm. The cable assist setup is fine for some applications, but I prefer full hydraulic.

[US1 Fountain]

I had the dual lathem add on on my last boat. Other than being a little harder at idle, I'd put it against any other full hyd steering in the safty feild. My drive was as tight as my current full Hyd steering. The cable will not see any forces. But then, maybe my cable wasn't worn out like apperanty so many others is.

Consider this, just how many fittings and feet of high pressure hose does a full hyd setup have? Tons of both. If just one of those fail, your drives will flop back and forth like a rag doll. With the add on, you still have the mechanical connection. So it must be safer.

[US1 Fountain]

You might be correct. Can't remember.

Just check a picture of my last boat with the add-on. Still connected to the tiller.

[Scott B]

Originally Posted by lchornet

I thought that even with only the add on, that you elimated the connection to the tiller arm. Cable moves the hyd cylinder inside the boat, that sends pressure to the external cylinders, which moves/holds the drive?

The tiller remains connected, but it serves as a refernce point for the brazil valve. I disconnected mine when I first did the half system install on a TRS, the steering went wacko...

[Whiteknuckle]

Ok, but does the tiller arm or the cable see any stress from the forces acting upon the drive? And explain to me again what the tiller arm does on the add on system.

[Falcon]

The external rams only take the place of the internal ram in the hydraulic circuit. The cable tries to move the tiller arm, which loads and moves the "brazil" valve, which opens ports to move oil into the cylinder(s). The cylinder(s) are either the internal stock ram or external add-on. It's an "assist" system. In reality even the full hydraulic is an assist setup with the valving in the helm.
In my earlier post I didn't intend to infer that a full hydraulic setup is safer, but it should handle higher loads before failure. Your point about the mechanical cable connection is worth considering in pros and cons.