Ronaldo47

Here's an explanation of why the voltage is higher immediately after a battery comes off charge, from a book on accumulator charging, see page 33 and graphs on page 34. It was published in 1942, but I don't think lead-acid technology has changed significantly since. The graphs represent behaviour using a voltage source higher than the accumulator, a series resistance being used to determine the charging current. On a boat, the alternator's regulator would prevent the charging voltage per cell from becoming as high as that shown in the graph. Accumulator charging 1942.pdf

I originally posted this observation about difficulties in reconstructing liveries from old photos in the "Tunnel Lights" thread. +++++++++++++++++++++++++ When reconstructing liveries from old photographs, you have to bear in mind that the early photographic emulsions were not sensitive to all colours. Thus the early "ordinary" plates were only sensitive to blue, and would render both red and green as black, the later "ortho" plates were sensitive to blue and green and so would render red as black, and the modern "panchromatic" films are sensitive to all colours, although still over-sensitive to blue unless a yellow-green filter is used. Ortho and Pan emulsions only started to be used around the turn of the 20th century, so virtually all Victorian photos would have been taken on "ordindary" film. Pan cost more than the other earlier types, which continued to be available to general-pupose photographers into the mid- 1950's. Edited September 27, 2021 by Ronaldo47

Many years ago I was able to give my children an impromptu mid-morning physics lesson on the effect of colour on heat absorbtion at a lock gate on the Southern Oxford. In the morning sunshine, the black part of the obviously freshly-painted wooden beam was bone dry and warm to the touch, whereas the white end of the same beam was decidedly cold to the touch and was still covered with drops of water from the previous night's rain.

Reminiscent of the renovation of the canal basin at Stratford-on-Avon in the 1970's, which originally was not provided with mooring rings. They also embedded the arc of raised bricks at the lock beams that used to provide grip for canal users in cement, presumably to make it more pedestrian-friendly.

A consequence of the change/glitch would appear to be that every boat owned by a hire company could bear the name of the owning company.

The only times I can recall overtaking taking place (both by our boat and by others) was during my first canal holiday in 1976 on the Grand Union main line South of Braunston, in places where the canal was wide and deep enough for it not to be a problem. Time was very much of the essence that year due to the very restricted lock opening times. We did not want a repetition of our first night, moored at the bottom of a flight of locks sandwiched between the M1 motorway and the London-Birmingham main line until 10.00AM the following day and a mile from the nearest pub, due to our failure to appreciate that the lock flight closing time was the time by which you had to exit the flight, last entry being an hour earlier!

I read somewhere that the optimum speed in a shallow canal is the speed of a wave. So if you go at that speed, you sort of ride your own bow wave. Unless circumstances dictate otherwise, that is the speed I choose.

We've got the Pass the Pigs game somewhere, but it must be around 20 years since it was last used. Good for keeping thd kids occupied when waiting around on holiday trips, small enough to be put in a handbag, and good fun. We never encounted the combination that was un-natural for pigs and resulted in disqualification of the unfortunate player!