To see as much of the world as we can,
Using the smallest carbon footprint we can,
Spending the least amount of money we can,
Making as many friends we can.

Team Red Cruising

Peculiar Failure Modes

Two very odd failure modes this week.

The freshwater pump corked off. While we have a guest aboard. Venerable Great Aunt Diane was perfectly happy using the hand pump until we could sort out the pressure water system.


The backbone of the freshwater system is a Jabsco diaphragm pump under the nav station. It might be a 36950-2000. It feeds the filter and pressure accumulator.

Symptom One

The initial failure mode was a tripped circuit breaker.

"Who turned off the freshwater pump?" The Commodore asked. The breaker panel is in a place where it can get bumped, so casually flinging things on the workbench/parts locker can sometimes bump a breaker.

As the day progressed, the breaker was found in the off position several more times. Not good.

Symptom Two

Eventually, we flipped the breaker on and watched the ammeter. Amps went from a normal 4 or so while the pump was running to 8 after the pump stopped. Then the amps grew, and grew until the breaker tripped.



Remain Calm.

We have over 200 gallons of water and a hand pump. We're tied to a dock. It's all good.


What's tripping the breaker? Clearly the motor's getting jammed. Jammed against what? The obvious answer is that the pressure sensor has failed. The motor runs until it cannot turn again and then trips the circuit breaker because it's jammed.

There's a remote possibility that a bare wire is somehow shorting after the motor runs for bit. But that makes little sense. The wire gets wrapped around something, shorts out the motor and the magically unwraps itself so we can run the motor again?

At this point, it looks like I'm going to have to order a pressure sensor for that pump housing. It might be simpler to replace the entire pump. I have two spare pump bodies. But no spare pressure sensor.

Hands On

Next day, with plenty of daylight, and the crew out of the galley, I could dig around under the nav station, where the pump sits. It's right awkward to work there. So I pulled the pump free of its rubber cushion feet so I could get a good look at it.

I rotated the belt manually and the pump pumped. Odd. It's supposed to be jammed.

I turned the breaker on and it pumped. Then stopped. Amps climbed. Breaker tripped.

I picked up the pump, spun the belt and it pumped.

The pressure's not "too high". It's not very high at all. It's barely at the normal 40 PSI for the accumulator tank.

Symptom Three

The belt was not centered on the big cog. So I rotated the pump, sliding the belt onto the big cog.

Then I noticed the actual problem.

The little cog on the electric motor was loose. Loose enough that I could slide it off the end of the shaft.


A few moments with a hex key and it's on good and tight. Put the pump back into place and everything seems to be running like normal. Maybe even better. The pump seems quieter. And it seems to be running less.

Instrument Panel Weirdness

We have Datamarine instruments. Part of the complete Datamarine package is an A180 control panel to turn on night light mode for the cockpit instruments. It also has a distance counter that shows the number 51950 and has always shown that number. It's never changed.


We're not totally surprised that the number has changed much, the distance log doesn't work reliably, either. It gets gummed up with algae and stops counting.

But it hasn't changed at all. At all.

Looking in the documentation folder, I found the Datamarine A180 book, and it had the wiring for the little wiring block. Looking up inside the navstation cupboard there's a loose wire with a spade terminal floating around near the wiring block.


That's the missing wire that might make the log distances register in the overall distance meter.

Why did the wire drop off?

It appears that there's no screw in one spot on the wiring block.


Cool. Root around in the screw drawer. Get out some screw drivers. And…

The screw isn't missing.

The screw head is missing. The screw's still there. How does a head fall off?

I had to take a pair of needle-nose pliers and slowly unscrew the shaft of the screw from the terminal block. It's sort of like a set screw without a place to insert a hex key.

Once the old screw's mortal remains were out, it's a matter of putting a new screw plus the loose wire in. We'll see what happens when we actually move. Maybe we'll start accumulating life-time operating miles.

That would be cool.

Grand Totals

I tallied 2,935 miles last year. The years before that were 531 miles and 280 miles. And, of course, I don't know how long this gizmo has been disconnected, so we could put a little sticker under the distance saying "add 3,800". Is that right?

It's likely that Red Ranger has been over 10,000 miles in her life. I know she went to the Bahamas once under the previous owner. That's good for 3,000 miles. If the previous owner racked up 500 miles a year for the next 20 years, then the 51950 on the counter might mean 15,195.0 miles.

[It most certainly doesn't mean 51,950 miles; that's 1,700 miles a year every year for thirty years. That's 340 hours every year at 5 knots. That would add up to 10,000 hours on the engine.]

The engine hour meter on the binnacle shows 2300 hours. If every hour was motoring at 5 knots, that could explain more than 11,000 miles. Sailing for 4,000 miles, 25% of the time, is certainly possible on the Chesapeake.

So I think the distance should say "Add 13,800".