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A22 Hydrualic steering upgrade


mtvnuccio

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After a full season on my 2020 A22 I was thinking about upgrading to hydraulic steering. Has anyone ever tried switching over from manual to hydrualic steering? I know that malibu offers the option on the Axis A22's. I would love to hear some input on the subject.

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Hydraulic steering should be fairly straightforward to install.  Do you have a specific reason to change?  Your steering cable should last pretty much the life of the boat if you keep it dry.

On thinking about it, I suppose you would not get any steering wheel pull at the helm even with a lot of rudder tab offset.

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The only downsides to hydraulic steering compared to using a cable would be the slightly higher steering effort and the cost of the system.  Hydraulic steering prevents the feedback pull that you would encounter using a cable, but if you have a leak and loose enough fluid you would have no steering, so maintenance is important.  Using an electric assist pump with the hydraulic system makes steering nearly effortless, but also greatly increases the cost of the install.

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so I've been scouring SeaStar's website.  I just sent them an email for clarification.  From what i can tell, the SeaStar Cylinder HC5312-3 (BA 125 ATM, Inboard Type) or HC5313-3 (BA 135 ATM, Inboard Type) seem to be right.  I also have questions about the pump (helm) I would need (and want).  There are 3 main options i need to figure out (maybe someone can chime in).  1) Does the factory helm mount vertically, or is it angled?  This dictates if I need the Classic or the Sport/Sport Plus model.  2) 1000 PSI or 1500 PSI pump?  This is the difference between the SeaStar and Sea Star Pro helms.  3) What pump volume (1.4, 1.7, 2.0 cu. in.) and how does pump volume affect steering characteristics?

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I presume that you would start by measuring or calculating the tiller load at worst case (probably ~50 MPH with rudder hard over), add some safety margin (probably 100% more force), then using that number to decide on the pump and piston combination you need.  Multiply pump pressure by functional piston area (piston area minus rod area) to get applied force.  The pump displacement determines how fast the piston moves, so you would match the displacement to the functional piston area to achieve the amount of force and turns required at the helm to move the rudder.

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looking at the "guide" on SeaStar's website, they dont go that far in depth for the cylinders.  They base it on length, hull type and if its pleasure/commercial.  I assume there are a too many variables to perfectly match the "correct" cylinder to all the different boats/conditions.  As for the pump volume, that makes sense.  Based on theory, the 1.4 would apply more torque (and feel lighter at the wheel) but be slower rudder action.  Conversely, the 2.0 would apply less torque (and feel heavier at the wheel) but be faster rudder action.  

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1 hour ago, Texan32 said:

looking at the "guide" on SeaStar's website, they dont go that far in depth for the cylinders.  They base it on length, hull type and if its pleasure/commercial.  I assume there are a too many variables to perfectly match the "correct" cylinder to all the different boats/conditions.  As for the pump volume, that makes sense.  Based on theory, the 1.4 would apply more torque (and feel lighter at the wheel) but be slower rudder action.  Conversely, the 2.0 would apply less torque (and feel heavier at the wheel) but be faster rudder action.  

They also seem to be confused about units.  I looked at their "Capilano" Technical Information, and it shows the cylinder stroke and volume (from which we can derive bore, e.g. volume/stroke), but then they try to tell us that the cylinder produces torque, and that the metric equivalent of inch pounds is kilograms.  Sheesh.  This kind of stuff drives me crazy, and manufacturers don't understand that people will just shop elsewhere.

The cylinder produces force, which you would convert to torque by connecting it to a tiller arm of a specific length.  Also, the metric unit for torque is newton meters, not kilograms (which is mass, not force, and not torque).

So if we can trust anything on their site, the BA-150-7 cylinder has a stroke of 7", a volume of 10.2 cu. in., and a functional piston area of 1.457 square inches.  That means it will produce a maximum of 1,457 pounds of force at 1,000 PSI.  It looks like they assume a 4-7/8" lever arm on the tiller to get their 7117 inch pound torque number since 4.875 * 1457 = ~7117.

They also don't state it, but I suspect that the displacement they list is probably per turn (360 degrees) of the helm.  If that is the case, the 1250V helm pump would adjust from six turns (10.2 cu. in. / 1.7 cu. in. per turn) to three turns 10.2 cu. in / 3.4 cu. in. per turn) rack-to-rack.  As I recall, the helm on my Sunsetter is about three turns rack-to-rack, so that combination might be a place to start when you talk to them. 

You are unlikely to ever need anything close to the maximum force in this application, since the rudders on these boats are relatively balanced and don't need much force at the tiller to operate them.

Verify everything with them before you buy, since I'm just some dude on the internet giving you free advice.

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16 minutes ago, justgary said:

They also seem to be confused about units.  I looked at their "Capilano" Technical Information, and it shows the cylinder stroke and volume (from which we can derive bore, e.g. volume/stroke), but then they try to tell us that the cylinder produces torque, and that the metric equivalent of inch pounds is kilograms.  Sheesh.  This kind of stuff drives me crazy, and manufacturers don't understand that people will just shop elsewhere.

The cylinder produces force, which you would convert to torque by connecting it to a tiller arm of a specific length.  Also, the metric unit for torque is newton meters, not kilograms (which is mass, not force, and not torque).

So if we can trust anything on their site, the BA-150-7 cylinder has a stroke of 7", a volume of 10.2 cu. in., and a functional piston area of 1.457 square inches.  That means it will produce a maximum of 1,457 pounds of force at 1,000 PSI.  It looks like they assume a 4-7/8" lever arm on the tiller to get their 7117 inch pound torque number since 4.875 * 1457 = ~7117.

They also don't state it, but I suspect that the displacement they list is probably per turn (360 degrees) of the helm.  If that is the case, the 1250V helm pump would adjust from six turns (10.2 cu. in. / 1.7 cu. in. per turn) to three turns 10.2 cu. in / 3.4 cu. in. per turn) rack-to-rack.  As I recall, the helm on my Sunsetter is about three turns rack-to-rack, so that combination might be a place to start when you talk to them. 

You are unlikely to ever need anything close to the maximum force in this application, since the rudders on these boats are relatively balanced and don't need much force at the tiller to operate them.

Verify everything with them before you buy, since I'm just some dude on the internet giving you free advice.

Thats some good math!  And good theory explanation.

I too do not like their documentation.  In one document they claim that a certain cylinder is (lets say) a 5 turn cylinder.  Another document states that a pump is 5 turns lock to lock.  Its confusing, but if you buy a "kit" it works.  They have already matched the cylinder to the pump and know its particular turn number to get lock to lock.  Otherwise, the answer isnt as simple.  Both pump and cylinder dictate how many turns it takes.  Im trying to imagine driving my boat and remember how many turns it takes  i feel like its just under 5.  But, im getting old and my memory eludes me. 

I sent them an email and will be sure to post up their response. 

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I agree that it shouldn't be this confusing.  As far as I know, the helm pumps do not have any stops in them since they are simply rotary pumps that would let you turn them forever.  The cylinder is what hits a stop, and the helm will stop because it cannot pump any more fluid in that direction.  I like the ability of some of their pump models to adjust the displacement so you can balance number of turns with torque required at the steering wheel.

Note also that they list a minimum steering wheel diameter also, and I'm not sure why they need to do that.  If they gave you the information you need to do the calculations, you can decide what is acceptable to you.  A smaller steering wheel means more required torque to get the same rudder motion (all other parts equal).  In other words, the wheel diameter changes the lever arm used in the helm rotary force calculation.

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I've watched a few install videos for the SeaStar system.  In the videos, it shows the bleeding technique.  I agree.  The cylinder causes the actual stop, not the helm pump.

I have several friends with hydraulic steering (double and single ended rams).  They use an orbital valve in place of hte steering box (unless its hydro assist).  Im assuming that because of the higher line pressure from the P/S pump, its able to bypass the relief valve.  I say this because every single hydro steering setup  ive seen allows the wheel to continue to turn after the ram has limited out.

I guess i didnt notice a minimum wheel size.  But either way, why does wheel size matter to them?!  Thats on the installer to figure out.  Only the installer knows what will/will physically fit.  Only thing i can think....leverage increases exponentially as diameter increases and they are worried about blowing out seals in the system.

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As far as I can tell, this is what Malibu uses for the 2020 Axis A22 hydraulic steering:

3632003, Helm 2.0 Sport Plus Tilt SP, HH6445

3632002, Hydraulic Steering Cylinder BA-135-7ATM, HC5313

3632104, Hose Kit, Port and Stbd, 2 x 20

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3 hours ago, csleaver said:

As far as I can tell, this is what Malibu uses for the 2020 Axis A22 hydraulic steering:

3632003, Helm 2.0 Sport Plus Tilt SP, HH6445

3632002, Hydraulic Steering Cylinder BA-135-7ATM, HC5313

3632104, Hose Kit, Port and Stbd, 2 x 20

Thanks for posting that!  i expected the cylinder.  I'm a tad surprised at the 2.0 helm.  i would think that a tad too aggressive on volume.  but the larger 135 cylinder might make it the right combo. I wonder how the 1.7 would do.  it would add (maybe) 1 turn lock to lock, but would should have a lighter feel.  That would be a small bonus at idle/low speed.

Edited by Texan32
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So its been a productive morning with email exchanges with Evan at SeaStar.  Here is what i can share.  He stated "the HC5312-2 is a direct replacement for cable systems as it is more powerful that any cable , the hc5313-3 takes that one step further and has a slightly larger cylinder bore for more power".  Now, given the information that @csleaver provided, and the fact that we run HEAVY boats, i think its safe to assume that the HC5313-3 is in fact that the right choice for cylinders.  Evan also supplied a chart that helps illustrate the Lock 2 Lock numbers for each cylinder.  According to the chart, with the HC5313-3 cylinder, a 1.7 cu. in. helm with result in 4.8 turns while the 2.0 cu. in. help will give 4.1 turns for L2L.  He also stated that with each pump volume change, you can expect 20-30 % increase/decrease in steering wheel force.

Im currently about 5000 miles away from my boat, so i dont know what the actual L2L number is for my boat.  BUT, im thinking that a HC5313-3 coupled with a 1.7 cu. in. pump (4.8 turns L2L) would be a really nice setup.  I dont run high speed.  I dont really care about tight turns while going mach 2.  What i do care about is ease of use at surf and wakeboard speed.  I also care about the how easy the wife can handle the boat when loading it on the trailer. 

SeaStar chart.png

Edited by Texan32
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1 hour ago, Texan32 said:

the fact that we run HEAVY boats

That will have very little to do with the force required to turn the rudder.  The rudder design and the speed in the water determine the force required.  You don't need more force than your current cable setup, so the direct replacement cylinder is probably your best choice.

I just went out and checked my rack-and-pinion system; it is 3.5 turns rack-to-rack.  That seems about right to me even if my boat were a bit longer.  The problem with too many turns is that you will find yourself having to whip the wheel too much, particularly at slow speeds.  Resist the urge to get wrapped around the axle on turns and force and trying to re-engineer what works.  Match your current steering number of turns and you won't hear any complaints from your wife.  If she notices that the force required to turn the wheel is different, remind her that it is better because she also doesn't feel the wheel pulling back against her.

With all of that in mind, if I were changing to hydraulic on my boat, I would go with the (from the table you provided) BA135-7 (8.2 cu. in.) and a 2.4 cu. in. helm to get a 3.4 turn rack-to-rack system.  Again, I would just match the number of turns and be done, but only after I verified the turns on my boat and the amount of cylinder travel I need (which he suggested is seven inches).

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I do understand/appreciate your points. I would love to order parts not and have them waiting for me when I get home from Germany.  But without getting hands and eyes on for myself, i cant drop that kind of cash blindly (pun intended). 

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the wife has a better memory than i do.  She remembered it was 2 1/2 turns from full lock to get centered.  AKA....about ~5 turns for our T23.  So, with the HH5313 cylinder, that makes the 1.7 pump the "matching" pump.

Does anyone have pics of the cylinder installed in a Bu or Axis?  Id be interested to see how they mount them to the hull.

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12 hours ago, Texan32 said:

... i cant drop that kind of cash blindly (pun intended). 

I stand corrected!  HC5313-3 cylinder, HH6491-3 Helm, 50ft of hose and 2 qts fluid ordered.  Hopefully i will have a install post in about 2 weeks.  :rockon: 

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2 hours ago, Texan32 said:

 

I stand corrected!  HC5313-3 cylinder, HH6491-3 Helm, 50ft of hose and 2 qts fluid ordered.  Hopefully i will have a install post in about 2 weeks.  :rockon: 

Well, that escalated quickly!

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10 hours ago, justgary said:

Well, that escalated quickly!

Seriously!  And its all @mtvnuccio's fault.  :lol:  But seriously, this is something i have wanted to do since i got the boat.  I'm in a fortunate position that I can afford the upgrade.  This post was the last nudge i needed to pull the trigger.  So, in all seriousness, thanks for the inputs.  @mtvnuccio, I'm sorry for bogarting you thread so much.

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