Hydraulic Steering in Multihulls

[trinescape]

I have had hy- drive steering for 4years and i have a single spade rudder and i also have a single outboard i have a ram for each it certainly makes docking easier to have directional steering on the outboard but when sailing i can isolate the outboard from the system and my steering becomes feather lite but in reverse the pressure on the wheel is twice that of forward motion .I recently fitted a coursemaster auto pilot and on standby i can see my rudder position at a glance the only problem i have encountered with alignment is with the out board and i made a timber jig so that when i re- engage it is parallel with the rudder. I highly recommend hydrive and being aussie, parts are easy to get they might not be the cheapest but for my money they are the best

[cooper]

Hi trinescape. Good to hear your experience. What length and weight is your boat? I have a mono with newly installed hydrive, but I think the cat guys would be interested in your situation.

[drewke07]

Once you have spent substantial time at sea you will find that going in reverse comes at the most oportune times, like when you are double reefed and it is blowing 30+, you go to tack and a wavs stops your progress and shoves you backwards. All it takes is a few seconds to develop pressures that on a typical multi partially balanced rudder far exceed any pressures you will find sailing forward. Or when you are trying to survive storm conditions the last thing you want to worry about is losing steering. Wise designers will calculat that possible load and provide a safety factor when designing the system. That is why it always appears to be overkill.

The diameter of the hydraulic ram along with the line size controls the pressures in system, and the volume of the helm pump dictates the amount of turns needed lock to lock. Kobelt makes a variable displacement helm pump that will allow you to dial in the turns you desire.

Savy designers like Crowther specify a cool little device that we have installed in the past that allows the operator to bring the rudders into alinment in a whitlock system (where the fluid goes from the helm pump to one ram, out to the next ram and back to the pump) by turning the helm lock to lock.

[ssullivan]

Here is some real info on my setup, in case that helps. Of course, I'm 34' (10 meters) and only 6 tons, but here is the setup on my cat:

SeaStar/TeleFlex BA150 Hydraulic ram x 1 (there is a bar holding both rudders together, which means I can never come "out of alignment")

HC5349 Seastar inboard Cylinder BA 150-7 TMB Bronze

This is combined with a Teleflex helm pump:

TELEFLEX SEASTAR HELM PUMPS - Hydraulic Helms by Discount Marine Supplies

It's all linked with 3/8" copper lines.

The fact that I have a rod between rudder stocks means I can't ever get out of alignment. Maybe something to consider if your hull design can accommodate it.

And a link to the company that makes my system:

Teleflex Marine - Welcome

[billyehh]

Sailrjim: It has cable steering which goes to the starboard rudder. There is a beam which connects to the port rudder. The designers put in a shaft from the helm to the stern. I can see the route from the Nav station.

[billyehh]

Oops. I did not mention that it was metal cable.

[44'cruisingcat]

It's difficult (although possible) for me to mechanically link my rudders. The hulls extend about 3 metres behind the bridgedeck, so I'd need a couple of bellcranks or similar. Also, I'm committed to hydraulic now, to try to install a mechanical system would be a huge job.

Bob Oram has said that a system that gives me 2-3 turns lock to lock will be perfectly fine as far as steering load goes.

What has really thrown me, is the communications I have had with Hydrive. They have been suggesting systems which are way beyond what seems reasonable to me. I also rang them, and the guy I spoke to seemed to by trying to convince me that hydraulic steering was some kind of mystery that ordinary mortals wouldn't understand. He gave me the impression that they wouldn't sell me anything other than the system they suggested, or perhaps they wouldn't support it afterwards.

I just cant see how a boat that could be steered adequately by a tiller less than 2m long, would need a system that can produce torque loads of 300kg/m. Frankly I feel that 1/10 of that would do the job. (30 kg/m being a fairly high 15kg load on a 2 m tiller)

I guess I won't be buying Hydrive.

[44'cruisingcat]

Originally Posted by ssullivan

Here is some real info on my setup, in case that helps. Of course, I'm 34' (10 meters) and only 6 tons, but here is the setup on my cat:

SeaStar/TeleFlex BA150 Hydraulic ram x 1 (there is a bar holding both rudders together, which means I can never come "out of alignment")

HC5349 Seastar inboard Cylinder BA 150-7 TMB Bronze

This is combined with a Teleflex helm pump:

TELEFLEX SEASTAR HELM PUMPS - Hydraulic Helms by Discount Marine Supplies

It's all linked with 3/8" copper lines.

The fact that I have a rod between rudder stocks means I can't ever get out of alignment. Maybe something to consider if your hull design can accommodate it.

And a link to the company that makes my system:

Teleflex Marine - Welcome

Sean, many thanks for taking the trouble to check out your system for us.

I can't easily link my rudders mechanically, it will have to be a 2 ram system. Keeping the rudders aligned shouldn't be a big issue anyway.

I'm going to investigate the Seastar pump capacities too.

BTW, my boat is 13.5 m and will weigh 5.2 tonnes.

[BigCat]

Originally Posted by 44'cruisingcat

It's difficult (although possible) for me to mechanically link my rudders. The hulls extend about 3 metres behind the bridgedeck, so I'd need a couple of bellcranks or similar. Also, I'm committed to hydraulic now, to try to install a mechanical system would be a huge job.

Bob Oram has said that a system that gives me 2-3 turns lock to lock will be perfectly fine as far as steering load goes.

What has really thrown me, is the communications I have had with Hydrive. They have been suggesting systems which are way beyond what seems reasonable to me. I also rang them, and the guy I spoke to seemed to by trying to convince me that hydraulic steering was some kind of mystery that ordinary mortals wouldn't understand. He gave me the impression that they wouldn't sell me anything other than the system they suggested, or perhaps they wouldn't support it afterwards.

I just cant see how a boat that could be steered adequately by a tiller less than 2m long, would need a system that can produce torque loads of 300kg/m. Frankly I feel that 1/10 of that would do the job. (30 kg/m being a fairly high 15kg load on a 2 m tiller)

I guess I won't be buying Hydrive.

Maybe you should contact another manufacturer of hydraulic steering systems, and see what they recommend. You could go with the smallest system that is recommended. If you go smaller than any manufacturer is willing to recommend, you may find out why the hard way!

[cat man do]

Originally Posted by 44'cruisingcat

Sean, many thanks for taking the trouble to check out your system for us.

I can't easily link my rudders mechanically, it will have to be a 2 ram system. Keeping the rudders aligned shouldn't be a big issue anyway.

I'm going to investigate the Seastar pump capacities too.

BTW, my boat is 13.5 m and will weigh 5.2 tonnes.

I looked at Capilano (seastar) as well through BLA.

It was pretty exy as shown in Sean's links, but the system was more realistic with its load calcs than Hydrives.

I still dont think they took into account weight and balance of boat, but just calculated off of the worst possible pigdog boat imaginable.

Incidentally, the last delivery I did had Hydrive steering and the pump pissed fluid all the way to Vanuatu from the front seal.

It was no real issue as we used Autopilot all the way (bypassing the wheel pump) and being a cat, was parked using the engines at the end.

Dave

[ssullivan]

Originally Posted by 44'cruisingcat

BTW, my boat is 13.5 m and will weigh 5.2 tonnes.

WOW!! Incredible! I'm a little envious. Very nice.

[44'cruisingcat]

Don't be envious! Your boat's in the water - mine's still in the shed!

[cat man do]

Originally Posted by 44'cruisingcat

Don't be envious! Your boat's in the water - mine's still in the shed!

Aint that the truth

Dave

[fastcat435]

Originally Posted by 44'cruisingcat

It's difficult (although possible) for me to mechanically link my rudders. The hulls extend about 3 metres behind the bridgedeck, so I'd need a couple of bellcranks or similar. Also, I'm committed to hydraulic now, to try to install a mechanical system would be a huge job.

Bob Oram has said that a system that gives me 2-3 turns lock to lock will be perfectly fine as far as steering load goes.

What has really thrown me, is the communications I have had with Hydrive. They have been suggesting systems which are way beyond what seems reasonable to me. I also rang them, and the guy I spoke to seemed to by trying to convince me that hydraulic steering was some kind of mystery that ordinary mortals wouldn't understand. He gave me the impression that they wouldn't sell me anything other than the system they suggested, or perhaps they wouldn't support it afterwards.

I just cant see how a boat that could be steered adequately by a tiller less than 2m long, would need a system that can produce torque loads of 300kg/m. Frankly I feel that 1/10 of that would do the job. (30 kg/m being a fairly high 15kg load on a 2 m tiller)

I guess I won't be buying Hydrive.

We are vvery happy users of the Hydrive system , the pump is the type 105 and the actuators are the stainless steel type cylinder 213 and this combination works perfect.
Our cat is about the same size and weight, we use balance rudders where 25 % of the rudder is forward of the rudder stock.
Greetings

Gideon

[Whimsical]

105 pump with 213 cylinders is what I have. Rated at 110 kg/m. But then mine aint in the drink yet so its nice to see others with the same size who are satisfied.

Mike