Rudder alignment problem on catamaran

[cakito]

Hi everyone,

Had been lurking these forums for a year but now it’s time i post something as i think this is the place where i can find some answers to problems of my catamaran’s hydraulic helm system. Thank you in advance for reading.

I need some help / ideas to figure out the rudder alignment problem i’m having with my 2019 Nautitech 46 catamaran.

The problem started after going through some rough seas and i haven’t been able to resolve it since then (more than a year now). Searching through owners group on FB, i found out the previous owner also struggled with this issue for a long while however they haven’t shared this with me before or after purchase (and cut all communication after payment unfortunately). Nautitech’s dealer who was the broker of my purchase also stopped responding for no reason known to me after acknowledging the problem was a hanging issue when i bought the catamaran. Nautitech tech support (if it exists) hasn’t responded to my emails and directed me to email the tech support whenever i call them. So here i am searching for a solution…

Below i’m listing all of the attempts & findings i’ve gone through in order to address this problem.

1) I have cruised with this catamaran around 2500 nm after buying it from its first owner without any rudder problems. This was a very smooth voyage with winds less than 10kn and a mostly flat sea conditions. This was until i had a 20-24 hr period of rough weather & sea at the end of my trip (40+kn winds and some serious waves). I had the autopilot engaged during the mentioned rough weather since it was a bit too dangerous to stay at the fly bridge during the storm.

2) The next day, while entering the marina i realized the boat wasn’t following according to helm so i relied on the engines to enter the marina.

3) After checking out I realized that the rudders were out of alignment. Starboard rudder was pushed all the way to its stopper on starboard end while port rudder was on the port side of the center. This explained why the boat wasn’t moving according to helm.

4) Bleeded air from multiple ports (on the pistons, at the highest point of the hose and also through LS RV2 drive unit. After leaving the marina, the problem resurfaced within half an hour, again bringing the rudders out of alignment. Starboard rudder was pushed all the way to starboard end stopper while port rudder was slightly on the starboard side of the center.

5) Hydraulics company checked out for internal leaks on the starboard side piston but said they found no leaks but still changed the seals. The problem unfortunately didn’t resolve but slightly got better?! The starboard rudder was still losing alignment but instead of within minutes, it was taking a few hours until it became unusable again as starboard rudder keeps losing alignment until it gets stuck at the starboard end stopper.

6) After aligning the rudders, the starboard rudder always moves toward the starboard direction. After multiple tests i can confirm that the
amount of unalignment between the rudders depend on time & strength of wave motion present on the rudders.

7) Starboard rudder loses alignment towards starboard direction around 15 degrees within 1-2 hours of sailing vs 24 hrs while moored in a marina and keeps losing its alignment until it hits starboard end metal stopper.

8) Bringing the bypass valve on the port side to open position and bypassing the port side piston doesn’t seem to make any change on the problem. Starboard rudder still moves toward the starboard direction with time.

9) The hydraulic shop said it was a sureproof solution to install a locking valve (?) on the starboard piston however it didn’t resolve the issue. Only thing that changed was the helm became stiffer. I got the valve uninstalled 2 weeks later as it didn’t seem to help at all.

10) Another hydraulics shop uninstalled the valve that’s right after the helm pump to see if it was causing some imbalance between the 2 rudder lines but problem persisted as before.

11) When the rudders are out of alignment, the helm gets slightly stiffer and gives an uneven resistance while turning it. When rudders are aligned, helm feeling also softens.

12) I turned all 3 valves on the RV2 pump to off position to bypass it but the problem still persists as before.

I contacted L&S local distributor but they said the boat needs to stay in their area for 10+ days to figure out what’s wrong where marina costs reach up to 3000 USD for just 10 days since it’s high season. They think the RV2 pump might be the culprit tho.

- First picture shows how much the ram moves within 1 hr while moored in a marina (around 1 inches).

- Screenshot is a basic diagram of the system but i think it doesn’t show the third hose going to the helm pump which is for feedback of autopilot i suppose ?
Hopefully someone can help me out of this nasty situation

[BigBeakie]

Is it possible the rudder stock is not securely connected to the steering quadrant, so the rudders pivot independently of the quadrant position?
Check that the grub screws or whatever clamps down on the rudder stock are really torqued down to spec.

[cakito]

Originally Posted by BigBeakie

Is it possible the rudder stock is not securely connected to the steering quadrant, so the rudders pivot independently of the quadrant position?
Check that the grub screws or whatever clamps down on the rudder stock are really torqued down to spec.

hi Bigbrakie and thanks for the suggestion. I’ve made sure that rudder is securely attached and doesn’t move by itself. Also both rudders seem to move freely without any major resistance when they are disengaged from the ram connection.

[Chotu]

Assuming rams are actually working properly and not allowing fluid to bypass internally:

Are valves F and C in the diagram replaced/new? One might have a small leak.

Why is the hydraulic autohelm pump showing 2 different pump components in the diagram? Each of the components looks like it's responsible for pushing in one direction only. Looks needlessly complex and might be the cause. Can you explain this?

All that's left after that is the helm pump itself.

The diagram is your friend.

Any component that bridges both sides of the system as shown in the diagram could be causing this.

One of the components that is bridging both sides is DEFINITELY causing this.

So carefully and methodically test or have tested each of those components.

Start with low hanging fruit. Just replace the realignment valves. Cheap. If there is still a problem, either have the autohelm pump or steering pump at the wheel thoroughly tested because those 2 are all that's left as a possibility.

Note:. This assumes rams are not leaking past internal seals. Also assumes you are not seeing any leaks or changes in fluid level in the main reservoir. And finally assumes the connection from rams to rudder is good. No spinning of rudder stock in clamp, no rotted out rudder spinning on the rudder stock itself.

[Chotu]

Looking at the pics again, definitely replace valves F and C. Thise look like off the shelf hardware store ball valves. Quite possible there is a leak in one.

[cakito]

Originally Posted by Chotu

Assuming rams are actually working properly and not allowing fluid to bypass internally:

Are valves F and C in the diagram replaced/new? One might have a small leak.

Why is the hydraulic autohelm pump showing 2 different pump components in the diagram? Each of the components looks like it's responsible for pushing in one direction only. Looks needlessly complex and might be the cause. Can you explain this?

All that's left after that is the helm pump itself.

The diagram is your friend.

Any component that bridges both sides of the system as shown in the diagram could be causing this.

One of the components that is bridging both sides is DEFINITELY causing this.

So carefully and methodically test or have tested each of those components.

Start with low hanging fruit. Just replace the realignment valves. Cheap. If there is still a problem, either have the autohelm pump or steering pump at the wheel thoroughly tested because those 2 are all that's left as a possibility.

Note:. This assumes rams are not leaking past internal seals. Also assumes you are not seeing any leaks or changes in fluid level in the main reservoir. And finally assumes the connection from rams to rudder is good. No spinning of rudder stock in clamp, no rotted out rudder spinning on the rudder stock itself.

Hi Chotu,

Thanks a lot for helping me towards a solution. Dwelling with the same problem such a long time, your efforts mean a lot to me. your points are all worth following up so i’ll start by replacing the by-pass valves (F & C) with proper ones to rule this one out. They are factory fitted valves and have never been replaced. They were tested for leaks but won’t hurt to install new ones as they show signs of corrosion anyway.

Regarding the bridging valves right under the helm pump; They have been uninstalled already. This hasn’t shown any improvement in the overall problem but at least ruled a component out.

After replacing the by-pass valves i plan to replace both rams with stronger ones to rule out internal leak possibilities.

Also about the final notes you’ve shared; I’ve checked all lines for leaks or possibility of snapped lines etc but haven’t found anything wrong. Fluid level is stable and is at optimal level as well. And both rudders have been checked to have properly attached & bolted to rudder stocks & rams with correct torques and components.

[Chotu]

OK. That’s great! Sometimes it can just get a little overwhelming with a complicated system. I understand.

happens to all of us sometimes

but just keep in mind the only thing that can cause this to happen, assuming everything is OK with those rams, is something that bridges both sides of the system. It’s actually that simple. You just have to isolate which thing out of the three things that bridge.

Good luck with it. I know it’s annoying and you’d rather be out there sailing.

[cakito]

Originally Posted by Chotu

OK. That’s great! Sometimes it can just get a little overwhelming with a complicated system. I understand.

happens to all of us sometimes

but just keep in mind the only thing that can cause this to happen, assuming everything is OK with those rams, is something that bridges both sides of the system. It’s actually that simple. You just have to isolate which thing out of the three things that bridge.

Good luck with it. I know it’s annoying and you’d rather be out there sailing.

thanks for the encouraging words, much appreciated 🙏🏻

So just to clarify on my end, do you think the RV2 autopilot pump might as well be a culprit?

[Chotu]

Originally Posted by cakito

thanks for the encouraging words, much appreciated 🙏🏻

So just to clarify on my end, do you think the RV2 autopilot pump might as well be a culprit?

any item in the diagram that bridges both sides of the steering system together could be the culprit.

And one of them definitely is.

so that does include the auto helm pump. there are check valves involved with that as well internally typically. At least with my system there are.

so unfortunately you have to suspect each item that bridges the two sides until you can definitely eliminate them.

[mikereed100]

Cakito,


I had the same issue with my hydraulic steering 3 years after launch. Having the rams re-sealed by professionals helped a little but the problem remained. I took the rams apart myself and discovered that one had developed tiny pinhole deformities on the inside. Replaced that ram and the problem was solved.



Best of luck

[cakito]

Originally Posted by mikereed100

Cakito,


I had the same issue with my hydraulic steering 3 years after launch. Having the rams re-sealed by professionals helped a little but the problem remained. I took the rams apart myself and discovered that one had developed tiny pinhole deformities on the inside. Replaced that ram and the problem was solved.



Best of luck

Hey 👋🏻 thanks for sharing this. sounds similar to what i experience after rams got resealed. i’m getting slightly bigger rams fitted along with new by-pass valves in 2 weeks hopefully 🤞🏻 will report back afterwards.

[cakito]

Originally Posted by Chotu

any item in the diagram that bridges both sides of the steering system together could be the culprit.

And one of them definitely is.

so that does include the auto helm pump. there are check valves involved with that as well internally typically. At least with my system there are.

so unfortunately you have to suspect each item that bridges the two sides until you can definitely eliminate them.

thank you for the clarification 🙏🏻🙏🏻

[cakito]

Originally Posted by mikereed100

Cakito,


I had the same issue with my hydraulic steering 3 years after launch. Having the rams re-sealed by professionals helped a little but the problem remained. I took the rams apart myself and discovered that one had developed tiny pinhole deformities on the inside. Replaced that ram and the problem was solved.



Best of luck

Looks like i was also going through something similar. I got rid of the crappy Nautitech bypass valves & LS rams altogether and replaced with them with much beefier versions. I’ve also incorporated the bypass valves on the rams itself which made the overall system more robust and simple. I’ve made around 150nm after the repair and so far so good. Happy that i’m not aligning my rudders 4 times a day during cruising anymore. Thank you all for your kind support & ideas.

btw the ram on the starboard side which was the main culprit, had issues with electrolysis which probably created the pinholes causing internal leaks.

[Tupaia]

Originally Posted by cakito

btw the ram on the starboard side which was the main culprit, had issues with electrolysis which probably created the pinholes causing internal leaks.

This is likely to be a reoccurring problem. Off the shelf rams tend to use chromed rods, subject to electrolysis just from damp or condensation bridging between the rods and the cylinders.



I suffered the same issues until I eventually had some custom Polished rods made from Duplex Stainless Steel. These require the seals to be replaced slightly more often but have resisted pitting from electrolysis for a decade now without problems.


With a hydraulic tie bar there will always be some situations where creep due to wear will cause misalignment. In my quest to find a solution I fitted a separate rudder indicator to each rudder and a remote bypass at the helm that facilitates immediate and easy realignment. If I find I need to use this there is a good chance the seals need replacing.

[cakito]

Originally Posted by Tupaia

This is likely to be a reoccurring problem. Off the shelf rams tend to use chromed rods, subject to electrolysis just from damp or condensation bridging between the rods and the cylinders.



I suffered the same issues until I eventually had some custom Polished rods made from Duplex Stainless Steel. These require the seals to be replaced slightly more often but have resisted pitting from electrolysis for a decade now without problems.


With a hydraulic tie bar there will always be some situations where creep due to wear will cause misalignment. In my quest to find a solution I fitted a separate rudder indicator to each rudder and a remote bypass at the helm that facilitates immediate and easy realignment. If I find I need to use this there is a good chance the seals need replacing.

thanks for the advice. I believe the new rams i got also have ss rods but i have to confirm this one with the hydraulics shop that custom made them for me. They look much beefier compared to LS rams Nautitech uses and also have the bypass valves included in the rams which allowed me to get rid of the poor quality valves Nautitech has used. The helm system on N 46 (2019) is shockingly poor quality compared to rest of the boat. Probably that’s also why Nautitech doesn’t even care about the helm problems with their boats.