Naiad Stabilizers Inop

[Juliet 15]

Anyone have experience with older Naiad 251 series stab systems?

Mine have been flawless till today. After engine start I put them in "center" as I idled out of the anchorage. I remember hearing the engine idle speed drop slightly like always when I flipped the switch from OFF to CENTER like they always do. Once clear of the Anchorage I flipped then to ON and thought nothing of it till an hour later when I thought we were rolling more than normal. The gauges showed the were stationary and centered. I checked they weren't pinned, then checked the pressure. Both gauges showed zero psi. I found a broken wire going to one of the rams, but fixing that made no difference. I stopped troubleshooting after that cuz I needed to drive. Anyone know the following?

1. If the engines are running but the system is electrically switched off (like a blown fuse) does the system pressure stay at zero?

2. The manual says nothing in the troubleshooting section about zero pressure. It does say there's an online fuse somewhere. I looked at the control head - nothing. Anyone know where that fuse is usually located?

3. Can a malfunctioning control box cause this, or is this a mechanical failure of a pump (kind of the same question as number 1 above)

 

[Insequent]

I can't help re: 251 as I have 252's. The only time mine have centred while running is when the cooling water circuit has a problem, and then I get an (oil) overheat light showing on the display panel. Then they switch off. I do not have psi gauges, so no idea what the psi is then, or at any other time!

Are you able to check that the hydraulic pump is operating? Mine is belt driven so easy to see the pulley turning on the pump, but some are driven from the engine transmission directly. Perhaps listening for oil flow in/out of the tank? With zero psi there is probably no oil flow...

 

[Russell Clifton]

My Naiad's are a 173 series. The way I understand how the system works is the pump is circulating the fluid as soon as the engine is started. (belt driven pump) The pump just supplies the flow, not high pressure. Once the system is turned on, a electric solenoid opens and lets fluid go to the pressure relief valve and then the control unit will maintain the high pressure the system requires to operate ( on mine 1250psi). There are two gauges on my control unit. One shows the operating system pressure and the other shows the pressure going to the gyro unit.

If your's is similar I would check: Belt driving the pump. Fluid level in reservoir.
System pressure and gyro pressure. Proper operation of the solenoid.

Here is a quote from my manual: A loss of system pressure may indicate an electrical disconnection at the solenoid valve, a pressure relief valve malfunction from contamination, or loss of pump prime.

 

[Juliet 15]

Mine sounds similar to your 173s. It has 2 gauges, one normally at 1250psi and the other normally at 520 psi. The fluid is full. Mine appears to be driven off the transmission directly. I'm hoping, because of the broken wire I found and fixed, that it's a solenoid/electrical issue.

Do you know where your solenoid is physically located?

 

[caltexflanc]

On the 252 the solenoids are mounted on the left side of the gyro assembly. It will show in your manual. You get out your handy multimeter and start checking continuity and voltage from there on back up to the helm. Are you sure the fins actually centered?

By the may I think Martin J is still on this forum, in this thread he says he has scanned copies of the manual

https://www.trawlerforum.com/forums/s4/naiad-stabilizer-rocker-switch-controls-30248.html

Also, give Naiad a call they are usually very helpful.

 

[Russell Clifton]

As galtexflanc says, mounted to the gyro unit, which is mounted on top of the control assembly.

The part with the wires going to it in these pictures(black with silver data plate attached to it)

 

[Kapn]

I’ve tested and temporarily fixed those solenoids by pressing down the plunger with a screwdriver.
In the second picture, see the black ‘cap’ to the right of where the wires go into the solenoid. The center of that is what you need to press down.
With the system running, when you push down the plunger the pressures should come up. That is, of course, if the solenoid failed.

 

[Martin J]

I had 251's on my previous and current boat and had a similar problem. In the main bridge control panel underneath there is a 2 amp fuse that protects the circuit board. I would whip the panel out and check that first. At least you can check the voltage going to the panel. People see the circuit panel breaker and think thats the only protection. But the sneaky pete's at naiad stck a fuse in the operating panel. Took me a few hours to discover this when I had a problem!!!

 

[angus99]

I also have 173s. Dave Yish, in their Connecticut office handles recreational consumer tech support (if he’s in the office these days): 203.929.6355.

 

[Martin J]

Sorry posted the hopefull cure in the wrong area. Fuse is behind the panel switch approx 2 amp. Pull 5"x2.5" panel out and its behind that. Had similar problem.

 

[Juliet 15]

I thought I'd closed this out. The solution was, as you suggested, the fuse. Unfortunately, the fuse was in an unmarked, in line fuse holder under the helm, about 6 feet away from the control box. It took me ages to locate it, and it was only by luck I found it. The fuse being used was .5 amps. No wonder it blew. I checked the manual and it calls for a 2 amp. I replaced the fuse (and marked it, and noted its location in the manual for next time, and for the next owner) and had no issues since.



Thanks for all the input!