Raymarine S3G autopilot tripping breaker?

[antoha]

Hello Sailors,

I was wondering if anyone has come across a similar situation, or had broader knowledge to help with the following autopilot problem.

We have a Raymarine S3G autopilot installed a couple of years ago, with not that much usage, all of it infrequent day sailing. The computer drives a below decks hydraulic B&G type2 blue linear drive (all of this bought new/old stock over a period of time). The equipment has a marginal number of hours on it.

Yesterday we manage to get out on the water (second time this season), and while the wind and waves were a bit more than what a 4 year old could handle comfortably (20 kts apparent, some chop; the boat is a 38 ft sloop, long keel, spade rudder, about 14000 lbs, long overhangs, going on 50 yrs of age), we're after all in the Long Island Sound, so I wouldn't call it extreme sailing or anything. We were making way under genoa alone, close to the wind, and the autopilot was managing well. Good and steady and wet; feet in the water and happy smiles.

Then we turned around as the wind picked up a bit, rolled the genoa in a little, started the engine just in case, and headed back. And here the autopilot tripped the breaker (30A, sized as per manual). Yes, following seas, boat not balanced and all, but again - we're in the Sound, and it's not howling (still 20 kts apparent, we are under half genoa and no main, and motor-sailing). I reset the breaker, tried to engage the pilot, and it tripped the breaker again. I tried again for good measure, with same result.

After we were back in calm water, and the wind died down some, I again reset the breaker, engaged the pilot, and it seemed to work. But earlier it kept tripping the breaker, and I can't say I was struggling with the steering at all as I had to steer manually. Nothing this boat (and at least some of us on the boat) hadn't handled before.

What could be going wrong, and how/what should I troubleshoot?
Many thanks, fair winds, and calm seas.

Anton

[DeepFrz]

Following seas, boat not balanced is the hardest point of sale for an autopilot to contend with. Also I think a big slab rudder. However I would start by thoroughly checking the wiring, all connections. Could be the breaker. Any chance some of the gear had been returned gear? Then check that the motor is free and running smooth. Maybe dismantle and check the planetary gears (I'm not familiar with the guts of that drive so may be misleading you here) and brushes, bearings, etc. An infra red thermal sensor may come in handy in checking all wiring connections, motor, breaker, etc.

[DeepFrz]

I found the manual here and see it is a self contained hydraulic unit. Some maintenance items recommended for the motor brushes.
https://manuals.bandg.com/discontinu...ok_IS-2533.pdf

[sailorboy1]

Originally Posted by DeepFrz

Following seas, boat not balanced is the hardest point of sale for an autopilot to contend with. Also I think a big slab rudder. However I would start by thoroughly checking the wiring, all connections.

My autopilot and rudder does much more complaining with a following sea that anything else and I adjust course to take off the stresses on the rudder. I doubt the OP has a wiring issue as that would have shutdown the autopilot on low voltage instead of tripping the breaker on high current. An autopilot breaker trip is just what it seems, an overload.

[sailorboy1]

Btw I find that my raymarine autopilot doesn't really like to be in Track mode on a "big" following sea as it causes it to really work hard to stay right on that track line. I found it is much easier on the system to leave on a course setting but not have the response level set too high and accept that there will be drift.

[antoha]

thank you.

DeepFrz: will look a the manual but given the small number of hours on the hardware, I'd be surprised it's due for maintenance. easy to test the mechanical side of things (connections for example), but how do you test the breaker?

Sailorboy1: I wasn't doing anything fancy with the autopilot, we never steer to waypoints or anything else fancy; always just steering to a compass heading. so I don't believe we were in track mode.

Still scratching my head. 30A seems like an awful lot for the situation. I really wasn't struggling much with the helm when I had to steer manually.

Anton