Self-Deception Passage

The Princess Bay excursion boat approaching us for the transfer of hydraulic fluid

June 12, 2015

We left our anchorage at Manzanita Bay at the late hour of 0815.  We had planned on a leisurely exploration of Rudyerd Fjord with no particular destination in mind.  Three full days remained to us before Mathias's flight out of Ketchikan, and we would not have to push very hard to get there. The barometer was at its highest point of the trip, and broken cloud coverage promised a partly sunny day for our tour of Rudyerd Fjord.

It became immediately evident that the thrust available from the engine and drivetrain were less than half of normal. Full throttle resulted in between 2 and 2.5 knots. Alarming. But the engine was running smoothly throughout its operating range. No parasitic oscillation, no strange sounds. If anything, it was smoother than normal. Puzzling. You can't hit a log or a rock with a propeller turning at 2500 RPM and not know it, right? We hadn't.  No signs of problems had emerged on the previous day. We had motored for 14.5 hours without apparent issues.

At least it wasn't engine trouble!  The engine sounded smooth and strong.  The prop could not have fallen off... that would have resulted in no thrust at all and too-fast shaft revolutions. A fouled prop, perhaps? We had the tool we needed to determine that, and used it: Mathias's waterproof camera would tell us if we had something wrapped around the shaft. I didn't take this possibility very seriously, as I presumed that anything that could retard our thrust by 50% would telegraph the problem through engine strain or vibration, of which we detected neither. It had to be in the drive train, no? But seeing is believing, and we took a couple pictures of the propeller.

Seeing is believing, but seeing is as cognitive a process as it is sensory
That day, I was blind... (but now, I see).

I will say in defense of my analytic failures that the screen of this camera is tiny and dim. We took a couple of pictures. Looking at them now, it is painfully evident what the problem was. But on the Behm Canal, with the growing sense that we had finally encountered a problem that we could not fix ourselves, tendrils of anxiety began to worry my judgment.

I got out the Yanmar service manual and read the chapter on the drive train several times. Hypotheses about what might be happening emerged. Guilt at having never changed the hydraulic fluid in the gearbox clouded my vision. The gearbox is 20 years old or more. Could the previous days of hard use have caused the gearbox to start slipping? At this point it was the only explanation that fit the facts as I understood them.  The murky images of the propeller were hard to interpret on that tiny screen, but rather than take more until I understood them fully, I had fixed on two pieces of evidence unsullied with ambiguity: (1) no THUNK, and (2) no vibration.

[SPOILER ALERT]
I know now exactly what happened, but I could not extract that understanding at the moment.  In setting the anchor the previous night, I had backed hard on it to be confident that it was set well. Normal procedure. Backing hard pushes the rudder strongly in one direction or the other, and in the picture it is plain that there is a propeller-sized scar on the rudder right where it would have been pushed against the prop.  I even have a vague recollection, fairly stronger than imagination, of having lost control of the tiller briefly as we were maneuvering in the stern-tie process.  No thunk, as what happened was the rudder was pressed against the prop blades, curling them in an almost symmetrical fashion.  It would be a six days and a rebuilt gearbox before I understood this.
[END SPOILER ALERT]

We had seen only one or two boats on Behm the entire previous day of 14 hours, and there was no cellular connectivity in the area, but Rudyerd Fjord has frequent visitations from excursion boats and float planes, so I knew we could raise some attention via VHF radio if need be. I checked the fluid level of the gearbox, and it seemed low, though not dry.  The hope that adding some fluid might solve the problem was the only straw available to me, and I grasped it. As I had no hydraulic fluid aboard, I hailed one of the excursion boats in the vicinity and explained my dilemma.  Another boat in the area, the Princess Bay, heard my call and volunteered assistance, recognizing that they were closer and could meet our need more quickly.  We gratefully accepted and in only a few minutes they were alongside. It was gratifying, to say the least.

These boats are large, fast catamarans, and it turned out to be a bit tricky to make the transfer. The skipper explained that his idle speed was 4 knots, and our top speed at that point was about 2.  But we managed, and they went about their business. The addition of fluid was, of course, in vain.

New Eddystone Rock, an iconic fixture of the Misty Fjord area.

Looking at the charts, we felt we had a good shot at making the 30 nMiles to Alava Bay by the end of the day.  The now-ebbing tide gave us a bit of a push, and we even ended up sailing part of the way. Alava Bay is on the southeast corner of Revillagigedo Island, where the Behm Canal empties into the channel to Ketchikan, and looking at the tide charts, it was evident that we would have the benefit of a flooding tide for a good part of the 24 nMile run into Ketchikan the next day, so our prospects were promising.  I had no idea how long it would take to make Ripple right, but we could at least get Mathias to his flight.

Sailing south towards Alava Bay late in the afternoon

We were safe, we had some thrust, and we had sails.