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man online shopping dreamstime m 77164280.640x283
I’ve just read a report suggesting that internet sales are really hurting the traditional chain stores. The number and frequency of retail stores that are closing in shopping malls is really quite alarming as more and more customers prefer to shop online from the comfort of their home.

In England recently I had to battle for space in a narrow country lane with a home delivery van from a supermarket. Nowadays you can order online and your weekly necessities are delivered right to your door, even to a remote shepherd’s hut in the middle of the moor.

If there are any remaining butchers, bakers, or candlestick makers left in English villages, they seem somewhat doomed. It’s enough to send you down to the pub for a pie and a pint, except they, too, are also closing in droves.

It seems social media is taking the place of traditional face-to-face social interaction.

Online shopping has become so easy, even returning stuff is a breeze. If something you bought doesn’t make you look as glam as you thought it would, or doesn’t do what you thought it would do, or if you simply don’t like it, then you can return it; no fuss, no muss. The web retailers now have really slick and well organized return systems that make this aspect of the transaction painless while not making it seem like you’re being punished for being such a dufus for ordering the wrong thing in the first place.

So, what’s not to like, and how does this relate to stuff we need for our boats?

solar boat dreamstime s 3929837
After several discussions recently with customers contemplating adding solar to their electrically powered vessels, there is still a lot of confusion about exactly how much power can be realistically expected from solar panels. I have an inkling that these customers are so honed in to watts and kilowatts from their dealings with propulsion that they assume that all watts are equal. But solar watts are a different animal.

The watt is a measure of power and is normally derived electrically from multiplying volts times amps (W = V x A), or amps squared times resistance (W = I² x R). So, using simple math, if we have a 5,000 watt (5 kilowatt, or 5kW) DC electric propulsion motor running on 100 volts, we would expect it to be drawing 50 amps at full load. If the same sized motor was designed to run at 50 volts then the current draw would be double that at 100 amps. For reasons of wire sizing and cost of ancillary equipment we’d want to keep the amps as low as possible, so the higher the voltage the better (except for having highly lethal voltages in damp environments). As you can see, the numbers are all very simply calculated and it’s all cut and dried, and it had better stay very dry indeed!

Solar watts are different, and I’m referring here to the wattage rating of the panel(s).

Feynman diagram dreamstime m 89989487In the wake of the recent celebrations of science and scientists, I could not let the occasion go without a mention of the late Richard Feynman. For those of you not familiar with the name, Feynman, as well as being a brilliant scientist, was also a fascinating human being and a bit of a maverick who delighted in upending normal thinking and throwing the occasional curve-ball.

In his second book “What Do You Care What Other People Think: Further Adventures of a Curious Character?”, Feynman describes how he was once intrigued at how the brain tracks time, and was curious to see how accurately he could gauge one minute by counting.

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