(Written by John) Famous last words ” I have an idea, let me try this”
During my normal watch period of 8 until 2 I decided to try and manual steer the boat for an experiment to see if we could get more downwind performance. I turned the autopilot off and tried to manually steer us downwind while easing off the Genoa sheet and letting it billow out in front of the boat. The time was around 10:30 am.
Well, that didn’t work, the sail collapsed and I thought no harm done just get it tightened back up and engage the autopilot. Oops. The autopilot had lost its mind. It would not hold a course and just headed off into never never land. Not good. An autopilot is literally worth three people on a sailboat. It relieves you from all the constant steering for hours on end. It never gets tired and steers a beautiful ruler straight course. And now it was dead.
We rolled in the Genoa, and started the engine and drove around in circles for a while turning the pilot on and off, hoping that maybe it just had a minor brain fart. Nope. Next I tried replacing the simplest part which is the compass module. Not that either. The time now was 11:30 am.
Time for major repair. There were only two choices left and it turned out that the steering ram had lost the feedback position sensor. We have a spare steering ram, so we “Hove to” which is where you basically put the boat into park. It will assume a position head first into the wind and waves and just gently drift downwind. It is a very common storm tactic or when you just need to take a break. It provides a stable boat so both Kay and I could work the problem. We shut off the engine and got to work.
We had to empty out all the cockpit storage on both sides to gain access to the part. Then remove the spare part from under the aft berth. Now take the old one out, which is a job for a malnourished midget as access to some of these places is pretty tight. We got the old one out, put the new one in, and……….IT WORKED!!!! It was now about 12:30pm.
So from failure to back on our way, two hours. The only reason we were able to do this so quickly is that it is NOT the first time this has happened.
We went back on our way and put the boat back together and I would like to say that happiness was felt by all. Unfortunately, that was not true. I got blamed for not treating the boat like a glass princess and that it broke because I was not watching out where we were going all the time. I responded that the failure was due to a part that is used in stereos to change the volume or the bass or treble. It is not designed to be turned back and forth 10 million times like the autopilot does as it steers. It is not designed for military or aviation use or even marine use, it is a consumer grade stereo part. In the case of this one, it was made in Mexico.
The Achilles heel of this electric autopilot and most of them is this 30 dollar part. It is called a rudder feedback sensor. It is just a higher grade 10 Kilo Ohm potentiometer which gets moved back and forth by the steering ram that moves the rudder. The brains of the computer constantly look at the desired compass direction and where the rudder is (which it knows from this 30 dollar part) and it then makes a decision on what to do. In other words it constantly asks itself left or right, where am I steering? left or right, where am I steering? If it no longer knows which direction it has steered because the sensor failed, the boat goes all the way over to one side and there is no hope until the new part is installed. In engineering we say that the feedback loop has been broken.
Fortunately I had done this before and actually had one of those 30 dollar parts on board. That night during my watch I took the cover off the ram we had removed, and saw that the inside was covered in graphite dust. A potentiometer is composed of a carbon ring with a wiper arm that moves around it. Over time, the carbon had just worn away leaving a dead spot on the resistor. This dead spot caused the feedback to go nuts and thus, no more autopilot.
The new part is installed, it is all nice and clean but I need to calibrate it and then wrap it up in plastic and put it away again until it fails in another 2000 miles. Unfortunately I can’t truly calibrate it 100% until we get to a dock where I can use the computer brain for the final tweaks. Let’s hope that the new one does not fail before we get to Australia. 3 to 4 more days.
To make the day even more fun, I noticed that the oil level in the main diesel engine had INCREASED. That literally cannot happen. Normally it loses a quart of oil every 12 to 24 hours of motoring. Not bad for an engine with almost 7000 hours and from 1992. The only thing that can be happening is that diesel fuel is leaking into the crankcase oil. This is bad because the oil becomes diluted and no longer lubricates the engine and it will fail.
After a couple of hours of google searching from the middle of the ocean (Thank you Elon Musk for Starlink) I think the culprit is the mechanical lift pump that takes the diesel fuel from the tank and feeds the high pressure injection pump. It is either that, or the oil seal on the high pressure pump has failed at which time I think I will need a more qualified mechanic.
I had one of these pumps fail on my old Toyota Celica. The difference was the Japanese were smart enough to say, hey if it fails, let the fuel drip OUTSIDE of the engine. That way, nothing bad happens and it is obvious there is a problem. Volvo went the opposite route, hey when it fails, the diesel will run into the engine, and maybe the owner won’t figure it out until it seizes up. That way we can sell him another engine! Good idea Sven, I am sure our boss Karl will give you a raise for that.
I found the part online in Australia and emailed them with the expectation of having a response in my inbox this morning. Oops, today is Sunday, I literally forgot what day it was! So here’s hoping they get back to me tomorrow and the part is in stock and I can have it shipped to the marina we will be staying at.
