Autopilot drive unit

[madmike]

I reported in some other posts that I have a NavPilot 711c and a Raymarine Type 2 Short mechanical drive; I didn't realize at the time of purchase that Furuno only recommends hydraulic actuators. On a recent trip through the Golden Gate, we had a brief pass through a current back-eddy that loaded up the helm. We could hear the drive motor turning, but the helm and rudder weren't moving.

So we're reconsidering this non-recommended configuration and looking for hydraulic actuators that will fit. Furuno has two drive units: PUMPLA11-12 and PUMPLA17-12. The smaller one looks a little undersized for our boat (Tartan 37, displacement about 11,000 kg). The Furuno website lists the 17-12 as "No Longer Available" but Defender still has it for sale. Is this product being discontinued? Will there be a replacement?

I'm also confused about the stroke of the PUMPLA17-12. The Furuno webpage (https://www.furunousa.com/en/products/pumpla17-12) says it's a 1.75" x 9" RAM, 11" stroke, and 12" Cylinder stroke. Seems like these 3 numbers should be the same, so which is right?

Other options we're considering are Octopus 1212LAM12 or B&G Type 1 (RAM-T1-12V) which are rated for 15,000 or 12,000 kg displacement, respectively. Can you confirm if these will work with the NavPilot 711c?

Thanks for the support.

 

[Johnny Electron]

It is very important that the ram be strong enough to control the rudder in strong currents. You might want to discuss your needs with Kobelt who purchased Accu-steer who produced those LA models. They offer newer types which offer Safehelm type sensors that you might find interesting. Ideally you should get a LA strong enough for your needs yet ensures a 10 second hard over to hard over time without being too fast. That is why adjustment knobs on these LA units are so helpful in adjusting the hydraulic flow.

 

[madmike]

Raymarine support thinks our symptoms sound like voltage fluctuations on the clutch. I'll be checking for a faulty connection or insufficient wire gauge. Am I correct that the TB3 Bypass/Clutch connector should be putting out a constant 12V (or whatever voltage is at the TB1 power connection)? Or does it reduce the Bypass/Clutch voltage like the Lecomble & Schmitt Ecopilot?

We're continuing to see the autopilot working 99% of the time with random clutch disconnects.

Thanks for the help.

 

[Johnny Electron]

The clutch bypass signal will be at the same voltage powering the pilot. As it is designed to trigger a relay, clutch signal isn't designed for larger current. If larger current is needed normally the installer would wire it to a small relay and let it put some larger power source over to the device needing such current.

 

[madmike]

Follow-up:

We upgraded the wire gauge from the autopilot computer to the clutch and installed a high current relay so clutch current isn't limited by the autopilot. Since that change everything seems to be working fine.

 

[Johnny Electron]

Thanks so much for the follow up.