We ran out of diesel during this morning’s generator
run. For some reason I thought we were
drawing off of only one tank, and therefore had been very lax in monitoring
fuel levels. I guess I had been waiting
for this to happen. It was a little disconcerting
to learn that we were dry on both sides. Oh well.
We already had a trip to the fuel dock planned in the coming
weeks before we leave for the Bahamas. I’m
glad we ran out when we did because I probably would have gone on the fuel run
without checking how much we had.
Running out underway would have been seriously inconvenient. Even though we can see the fuel dock from our
mooring, there’s an overhead wire we’re too tall to go under, and we have to go
the long way around Boot Key.
On the bright side, this is a good opportunity to graduate
the fuel gauges and dipsticks, and find out how big the tanks really are. We’ve been operating on the assumption that
the tanks are 100 gallons each, but don’t really know for sure. And when the gauge says 50%, we don’t know
how much that really is because the tanks are not a uniform shape. Nor do we know how much fuel the generator
and engines really use. So we don’t
really know much at all.
Truth be told, we do have a fuel transfer pump, so we could
have found some of these things out before now.
But it will be easier with the calibrated high speed pumps at the fuel
dock, if we can get them to let us sit there long enough.
We do know that the fuel tanks are clean. First, we had the fuel polished before delivering
the boat from Fort Lauderdale. This is
where they cycle the fuel by running it through a filter and blowing it back in
under pressure to loosen up more gunk. I
was not there to witness the process, but I have since been told the only way
to really get it clean is the open them up and scrub them out. So we did that and found there was quite a
bit the polishing didn’t get.
Interestingly, there was a pile of something granular under the
starboard fill pipe. I figured it was
either sand or sugar. Either way, it
seems someone was attempting to sabotage the boat. Not telling when it happened, but fortunately
there were no ill effects. With the
tanks now empty, we can see that the bottoms are still squeaky clean.
So if we had 200 gallons when we filled up 140 days ago,
that would be a burn rate of 2.8 gallons per day, which doesn’t seem very
good. Most of it is generator usage, but
there is also probably about 300 miles of motoring in there too. Unfortunately, we don’t have functional hour
meters on the engines. The generator has
one, but I don’t think it is correct because it is way high.
I’ll dinghy over the fuel dock today (it is time for that
anyway) and get 5 gallons of diesel. I’ll
put that in one of the tanks and see how much generator run-time that gets us. Then we’ll start keeping track of the generator
hours, and I’ll install new engine hour meters so we can keep track of those
too.
The gallons per hour calculations should produce pretty good
data. Even though an engine burns fuel
at different rates depending on load, our loads are fairly constant. Our battery chargers max out at 33% generator
capacity and only charge at that rate for a short time. So the generator is just loafing most of the
time. When underway we usually run the
engines at about the same RPM, which is easy because its right below the point where they smoke and shake the boat. We generally only use two for manueverability or to power into wind and waves. Otherwise, we go about the same speed with just one.
Getting the boat to the fuel dock might be a challenge. It is going to take a good amount of fuel, or
very flat water, to keep the pickups submerged.
The weather pattern we’re in makes it pretty bouncy outside. Too bad there isn’t a fuel delivery boat here
like they have in Fort Lauderdale. Maybe
I’ll run them out of jerry jugs instead of the tanks. Yeah, that sounds pretty good.
Once we get to the fuel dock, the plan is to fill the tanks
in 10 gallon increments, at which points we’ll mark both the dipstick and the
fuel gauge for each tank. The dipsticks are
made of smooth stainless steel rod and it is very difficult to see the fuel on
it. We plan to score the rod with a Dremel
tool and a cutoff wheel. Hopefully the
marks will retain a little bit of fuel that will be easier to see when pulled
out, and still be visible through the inspection port.
With meaningful graduations, maybe I'll actually look at the fuel gauges more often. And armed with burn rates I can put together a nice spreadsheet to predict when we'll run out again.
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