May 14, 2015

The case of the jiggling chartplotter

I WENT FOR A RIDE in a powerboat the other day, the first in many a year.  It was a smart-looking trawler type, disguised to look like a 30-foot tugboat. It belongs to my friend Jere and his partner Sue, who were taking it for a run after an extensive overhaul.

No expense was spared, it seems — brand new engine and transmission, new wiring, new electronics, and all the bits and pieces that are needed to make a powerboat work.

One of the pieces of electronics in the wheelhouse was a computer screen that could be toggled  to show a color GPS chart, a depthfinder, a radar display, an AIS display and Lord knows what all else. And not only toggled, but overlaid. You could, for instance, overlay the GPS chartplotter with the radar display, just to be sure that the island you saw on the radar was also marked on the GPS chart. Of course, you could also confirm that fact by looking out of the window, but it’s obviously very comforting to powerboat people not to have to depend anything as low-tech as Eyeball, Mark I.

I must say that all went very well. The weather was kind and the new engine purred with a feeling of suppressed power. A mighty wake curled up astern and a big dial in the new teak instrument panel pointed to how many gallons of fuel we were consuming every minute.

There was just one disconcerting occurrence. The new GPS chartplotter rolled with the boat. By that I mean that as the boat rolled to starboard, the electronic chart rolled to port, so that it stayed upright, as if it were somehow on gimbals. Not the whole screen, you note. Just the chart showing on the screen.

Now it’s all very well to have a chart that’s always aligned with the horizon, but it’s a little awkward to have to twist your head, or the top half of your body, to line up with the chart every time the boat rolls one way or the other.

On any boat that I ever owned, the paper chart and the person consulting it rolled together, so that due north and top of one’s head always happily coincided. On Jere’s boat, it was very strange to have to keep twisting one’s neck in order to keep one’s eyeballs in the same relative position on the moving chart. Except that it wasn’t the chart that was moving, of course. It was staying dead upright, just like the galley stove, while my head moved with the rolling boat. I hope I am making all this perfectly clear.

Nothing that Jere could do in the way of pushing or sliding his fingers against the touch screen made any difference to the jiggling chart. I suggested it must have something to do with the radar interface. The external radar antenna is often gimbaled so that it stays level with the horizon. It must be either the radar or the galley stove, I said. But since neither the radar nor the galley stove was switched on, let alone overlaid, my suggestion was not received with great gusto.

Jere is a man of great skill and patience, and I’m sure he will get it sorted out sooner or later, if just for the sake of any susceptible guests who might find themselves going green while watching that jiggling chart. Meanwhile, I’m afraid someone is  going to have to rip the plastic covering off the instruction manual and read the bit about how to cure a jiggling chart.

I know, I know, it’s admitting defeat; but somebody has to do it. Sue is very organized and she can read.  That’s a good start. Maybe she’s the one to solve the problem.

Today’s Thought
What we call “Progress” is the exchange of one nuisance for another nuisance.
— Havelock Ellis, Impressions and Comments

 “And where have you two been all day?”
“Hi Mom. Daddy took me for my first visit to a zoo.”
“Oh, how nice.”
“Yes, and one of the animals had a full house and made Daddy pay $50 over the table.”

(Drop by every Monday, Wednesday, Friday for a new Mainly about Boats column.)

No comments: