Cable Assist Hydraulic Steering Vs Full Hydraulic
 

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.

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

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

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

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!

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

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

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

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.

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

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. :D

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

You might be correct. Can't remember.

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

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

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...

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

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.

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

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.

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

I added a single assist to a single engine 25' vee, it added a margin of safety, but it was not easy to deal with for the same reason I'll mention later. My current twin 27 cat came with an assist system as well. As for the problem.....especially with twins, when you want to quickly initiate a turn, you meet with a lot of resistance.....you are mechanically havining to initiate movement of the stern drive.......once the stern drive starts to move it feels alright......you think well if its just with quick movements I can handle it for the cost and hassle difference. I could not, this made putting the boat on the trailer much more difficult and avoiding drift was very fatiquing. And I'm not an expert on cables, but I can tell you there is a lot of stress on the cable to initiate movent of the stern drive and the cable will wear much faster than the stock set up. I put a hydraulic helm on my twin and can tell you that it was the best thing I've done to the boat. My wife before I put it on was very nervous that she could handle the boat, now no sweat. Eric

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

So are we saying that the extra strain on the cable is from steering wheel input to "energize" the valve direction and not from forces outside the boat? It appears to me that there should be some solution to this. I am not trying to be convinced, I just want to understand.

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

Full hydraulic has the most capability for maximum steering loads. "External" cylinder assist is next and is much better than the stock cable "internal" cylinder assist.
As for the wheel effort at the dock, that has a lot to do with pump rpm at idle when compared to cylinder volume. The "brazil" valve also can cause some extra problems with this at idle, usually helped by increasing the pump rpm. That valve was sized for the needs of that small internal cylinder.

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

How do increase the pump speed, by putting a smaller pulley on it? Does this significantly help?

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

I think full hydraulic steering is the only way to go. I installed a full hydraulic dual cylinder system on my 28' single engine scarab last year. There is absolutely no play in the drive. I can now let go of the wheel while cruising and it roles right along in a straight line. Also i can now steer the boat with my pinky finger. It cost more but I think every performance boat should have hydraulic steering

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

Nauti,
Yeah, I'm glad you like it and I'm sure that its great, but the question is why is it better and "safer" than the cable actuated system. I want to know why full hydraulic is safer. There are many people that just repeat what others say about everything without knowing the mechanical reason why. Thats what I'm asking for, and Falcon is trying. Break it down and make it simple to understand.

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

Scarab
Look at your current pulley ratio. Some older stuff had pulley ratios of about 2:1, pump turning about half of engine speed. You want about 700-800rpm pump speed at idle in gear. That's close to 1:1. The pump maximum rpm should be kept below 5600 for sure. So 1:1 works out ok on most engines. I think the peak output of the pump is before 2000rpm, so turning faster than 2000 doesn't really help, but is necessary to get the slow speed and idle to work. That's the pump stuff in a nutshell.
Whiteknuckle
I prefer full hydraulic, but I understand the cost effectiveness and "mechanical" hookup as being strong advantages of the cable setup. An improperly installed full hydraulic is probably worse than a well done cable system, but I still prefer the full system overall. Like most things in life there are pro's and con's to both.

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

this is great input, anyone have some installation drawings to further show how all this gets hooked up and used???

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

Falcon,
Here is a really really dumb question. On a car with variable power steering assist where the faster the engine turns the less power steering assist you get, how does that work? Is it on some kind of a clutch that turns the pump faster at low RPM? It would seem that could be what we are looking for at low engine speeds at idle for more assist!

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

Sorry I didn't help on my last post let me try again. If you were to go out and grab the cavatation plate on a cable system and jerk it back and forth with your hand you would have about a two to three inch movement(back and forth/slop) in the drive. if you are running down the river/lake and hit a wave or set of boat wakes in any other position than perpendicular to the wave; the boat has a tendency to jerk to one side. Hydraulic steering helps tremendously in this situation. There is absolutely no play in the drive with hydraulic steering, which helps with the tracking of your boat in rough water situations and hitting waves on an angle. Also if your boat chine walks at high speeds it can be dangerous with a drive that has steering play in it. Hope this post helped better.

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

If I added external add-on rams can I still at some point change my helm and use the same rams? Are these systems upgradable? I added on the steering this winter but have not used it at all. My boat never chine walked or had any problems what so ever except when I tried to run a Hydromotive prop that had so much stern lift that the boat felt like it had absolutely no steering what so ever above 70mph. The only reason I added the system is because I can run 75 or so and I wanted to be safe, fearing that the internal ram could passibly fail at that speed and cause the boat to go out of control. I know I have solved the problem with the add on steering, 75 is not 105 so it should suffice for what I need but after reading this thread if I cant steer it at idle or my wife cant steer it at idle that would pose a definant problem.

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

Yes, you can upgrade later...

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

My 26" scarab has the normal cable / Hydraulic steering, with a single external ram. Is it normal that both inter and outer rams are hooked up. Also at idle it can be a pain to steer does that mean that the pump pulley is to small??

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

Mine was only noticebly harder if I thought about it, otherwise it was not an issue. The wife would load the boat on the trailer, she never said anything. My only issue would be trying to turn it to fast at idle. Even then it was not a 2 handed operation. I wouldn't loose any sleep over it. Install the add-on now, then upgrade to the full at a later date if you decide you want it. Hardest part is drilling the holes in the transom. ;)

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

Scariest part for sure.......... It just didn't seem normal to break out the drill and that huge bit and go to town on the back of my boat!!! I used a rotating laser to make sure I was lined up perfect from side to side. My neighbor thought I was crazy but it worked perfect.

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

You did level the boat 1st, right? :D

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

Thats funny, I dont care who you are, thats funny........ :drink:

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

I really don't know how they do the variable assist stuff. It's probably some type of ecu/speed/variable-port setup. Changing the pump rpm only varies the "available" volume of oil. The pump is always circulating oil, even when the wheel is not being turned. This flow rate determines the rate at which you can turn the wheel, hopefully at least as fast as you would like to turn it!

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

Nauti-Boy
I understand that the stock cable system with no hydraulic external cylinders has slop in it from side to side. Now, what if you had the "add on" system. The cable actuated hydraulic system. There should be no play in the drive because the hydrualic cylinders has it locked in place. So, we are getting back to my original question. Is the drive any more solid with the full system than it is the full hydraulic system? What makes the full system safer? Is the strain on the cable only due from steering wheel input or is the strain on the cable due to outside forces acting on the drive, which is the primary reason to change to external hydraulic cylinders in the first place.

It appears to me that the primary difference between the 1/2 system with the cable and the full system with the hydraulic helm is the method by which drive input is recieved by the shuttle valve. Is this correct? If the cable is in good condition, why would it be unsafe? I also understand there may be some inherent slop in the cable helm, resulting in some wheel play before the actual input is realized by the hydraulics.

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

I asked that question to the sales rep at the Miami boat show. His reply was that by putting the external rams on, you get the safety factor. By going to the full hydraulic helm, you get the ease of steering. Again that is just sales rep talk.

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

IMCO's brochure says that the add-on systems are not recommended for over 70 MPH. It does not say why.

I upgraded my add-on system to a full system over the winter. I haven't tried it out yet but I will report my findings in a few weeks.

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

I have standard cable steering with a tie bar and my drives dont move at all. If you have that much slop youve got other problems.

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

I'm thinking that Scarab28 response may be starting to get close to the heart of the matter.

I'm wondering how many people have seen the cable in cable steering break. If one checks the condition of the cable at least once a year and replace it when it becomes suspect, I would think it would be very reliable. Breaking cables are rare, and the cable does not know how fast the boat is going. Does this make any sense?

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

I converted my '97 HP500 steering to WPM dual ram and had very little assist at idle. I was able to remove the p/s pump adjusting bolts and belt, and swing the pump down to modify it. You remove the pressure line (with a coffee can to catch the fluid). Next, unscrew the fitting that is on the pump. There is a spring behind it , and note the orientation of the valve when removing. Simply drill the orifice to the inside diameter of the hose fitting, around 3/16". Clean shavings, reassemble and top off fluid. MUCH better at idle.
This is the same principal modern cars use, they restrict the orifice at highway speeds. At idle, you need more assist.

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

There isn't a "shuttle" valve, well not exactly. Anyways, I really don't like to say one system is "safer". The full hydraulic just has more ultimate load capacity. Remember that the cable system always has "feedback" to the wheel. It only "assists" the cable movement, it doesn't matter whether it's the standard internal cylinder or externals. The externals can have less feedback because of total cylinder capacity, but it's still there. Feedback is "load" on the cable.
You might want to try the cable add-on system and see if it satisfies your expectations. You can upgrade the add-on system by installing a helm and lines later if you think you need it.

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

Not really. If you lose the power assist on the add-on system you lockup tight and can't steer because the cable cannot overpower the external cylinders without assist. So if this happens during a high speed manuver and can't correct.....you can guess the rest. Just as bad as losing a steering hose in either case. JMHO

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

I would rather the steering get locked vs have a drive that can turn without warning and toss the driver. At least with with it locked up, you are still going in the same direction and can pull the throttle back.

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

Thank you HP350SC on that tip with the PS Pump. Also Falcon on some great information. Lets talk about what would happen with the cable helm system if the cable or any other mechanical part fails. I'm not talking about a gimbal failure but a steering failure. Also, is the cable assist system more suitable to a lighter boat than a heavier boat?

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

"I also understand there may be some inherent slop in the cable helm, resulting in some wheel play before the actual input is realized by the hydraulics."

I had a cable helm with external hydraulics. The play in the wheel was 7" and made the boat horrible to control at slow speeds and unpredictable when launching out of the water. I ordered a new helm and was able to take some slop out for a couple of months. Then the slop would return.

The last straw was on a fast run I launched and the girl behind me screamed (having fun scream but sounded like she just saw Freddy) it made me turn around real quick to make sure they were O.K. when I did this I turned the wheel as I turned around. When I hit the next wave coming down the boat hooked enough to scare the crap out of me. remember the slop part of the wheel had no resistance.

I installed the full Hydraulics to the helm and have enjoyed a nice solid wheel ever since I was surprised how much I really had been compensating for the slop.

The job was not too bad and I was able to do it on my own in the off season. Once again I was surprised how much of a change in the wheel it made. Worth every dime I spent and if I bought another boat without the hydraulic helm I would figure it into my costs.

Sorry I have no exact technical science just real experience and what worked for me :drink:

Re: Cable Assist Hydraulic Steering Vs Full Hydraulic
 

Something else had to be wrong to have 7 inches of play. There are a lot of boats that come form the factory with cable assisted hydraulic steering. I can not believe they are all that bad.
I will find out this season. I installed cable assisted steering in my boat this fall after calling at least 10 different companies. They all said cable assist should be fine for my application, since my boat tops out in the 70's, but full would be better. Full should be better, it costs another 1200-1800 dollars.