Question re: auto pilot

Has anyone retrofitted an older trawler with an auto pilot? Is this a possible "do it yourselfer" or strictly a hire out? Is it insanely expensive? We'll be hand driving by the wheel from WA to AK so any advice is welcomed. Thanks, Jan and Will

I did. Do you have hydraulic steering?
I wouldn't leave home without it.

We do have hydraulic steering. How did you go about doing the refit? Our boat is presently in Tacoma but heading for Sitka end of August.

I just finished a Si-Tek install in the Spring. It's totally possible to do it yourself. Can you do it? Only you can answer that. It certainly wasn't the easiest thing I have done. There were lots of wires to run, hydraulic hoses to measure and have made, and a lot of gotchas along the way. There are easier ways than the way I did it to install one, but I like to make sure I think it through and try and minimize future problems.

I can post a few pics of the finished product if you would like. Chuck at Trawler Beach House has a pretty good write-up about installing his Garmin. Do your research though. I would tip my hat to getting a Si-Tex (rebranded ComNav unit) system. It's about half the price of the Garmin and Raymarine units. My SP-70 is at the end of its development cycle and ALL the kinks have been worked out. They are about bulletproof. Nor does it belong to the software-gimmick-of-the-year club. It does two things and two things ONLY. Pilots a straight course or follow a navigation course via NMEA1083 from my chartplotter. I can't do figure eight's in the water, conduct search patterns, or write my name in the river ;-)

Anyway, you need to be pretty good and several things to do an auto pilot install. Seeing that you didn't touch on your skill set, I can't say if YOU are capable of it, but I can say that I did it... and I would guess that many other here did it too. Go look at the online manual for the unit you are interested in and give it a read. You'll know quickly if you can or not.

Tom-

"and I would guess that many other here did it too. Go look at the online manual for the unit you are interested in and give it a read. You'll know quickly if you can or not."

I did it with a raymarine unit.

pretty easy if you have about average handyman skills but above average reading direction skills...something really lacking in America today....

psneeld said:

pretty easy if you have about average handyman skills but above average reading direction skills...something really lacking in America today....

Click to expand...

One job from my past was in Records Management. I saw a lot of vendor manauls, all of which had large print on the front page warning of dire consequences if the user didn't read and understand the entire manual.

Except one. This vendor had resigned themselves to reality. Their large print on the front page said:

"When all else fails, read this manual".

Not mentioned is interfacing with your plotter/GPS if you have a relatively new plotter, you may wish to stick with the same brand choosing a model that will easily interface.

Newer models use NMEA 2000 which can be plug and play within the same brand/model level. Having a good interface will make your user experience much better. On current Garmins, once you enter a route on the plotter, a screen pops up asking if you want the pilot to steer the course - no need to even use the pilot control pad - all operations take place on the plotter. Depending on your plotter, you may or may not have this type of functionality.

On my slow-speed trawler, I am in auto pilot 90% of the time - in nav mode at least half of that. You will wonder how you ever cruised without a pilot once installed.

Location of the compass is really important. Also calibrating the rudder feedback unit. If those are installed to specs, other tweaks can be done in software.

I installed my Si-Tex SP70/80 by myself. I have hydraulic steering so I installed a pump, rudder feedback,compass, computer unit, Sp80 station at main helm and Sp70 second station at fly bridge. My radar uses the AP compass NEMA 0183 output as a heading senser and the autopilot uses my chart plotter NEMA 0183 output for navigating. I have been very happy with the Si-Tex autopilot. It seems to be both robust and well designed. My total install cost was just under $2K

I had an old Sharp autopilot and was able to use the old pump. That saved a lot of time and money.

Joew2604 said:

I had an old Sharp autopilot and was able to use the old pump. That saved a lot of time and money.

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I was hoping I might be able to salvage some parts the PO left behind, too:




I haven't had time to do anything more than just snap these pics. I'm not even sure what that second one is. There is still a functioning rudder position indicator at each helm, obviously this is the source. It may or may not have been part of the original autopilot package. The helm display unit that I assume controlled the whole thing is long gone.

Anyone recognize these devices?

I think the top photo is a lineal actuator (is it going to the tiller arm?) - bottom is the rudder feedback unit (the brass cylinder with rod to tiller arm). The black box in bottom photo - i don't recognize.

I too replaced an old Sharp Autopilot. It had a wagner pump and a substantial looking rudder feedback. Alas the pump drawed too many amps and blew a fuse in my new Si-Tex AP. The new little octopus pumps that are used today are so much more efficient. I sold the old wagner pump on ebay for $300 nearly the cost of the new octopus pump. In general what I have found is that old stuff is best replaced. In my case there was 30 years of improvement in materials, efficiency, and functionality to be gained. It is true they don't make things like they used to; I believe for the most part they make them better. Put in the new stuff and sell the old stuff to folks that think the opposite is my mode of operation these days.

Our thanks to all for posting these very helpful replies!! We'll keep you posted (no pun intended) Jan and Will

Tom B - yes we would like to see px