Autopilot drive unit

madmike

Member
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.
 
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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.
 
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.
 
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.
 
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.
 
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