Ronaldo47
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Posts posted by Ronaldo47
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Interesting. I believe that Ortho films were only available in sheet film by 1965, but even today Panchromatic films are overly-sensitive to blue, and to get the best approximation to correct tones it was recommended to use a yellow-green filter. I managed to find one that fitted my camera in a camera shop's bargain box, and it certainly allowed clouds to be distinguished from blue sky. Without it, clouds and sky blended into a featureless white area unless you did some selective shading in the darkroom when making enlargements. Kodak used to do a range of "Wratten" coloured filters for use with black and white films to deal with the sort of problem you describe. Of course with film you wouldn't know there was a problem until after the film was developed.
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The accomanying scan is a better example of how non-panchromatic films rendered coloured objects. The scan is a composite of pictures from "Hornby Dublo Trains" by Michael Foster, 1984 edition, and shows black and white photos of tank wagons that must date from 1939, next to colour photos of their essentially identical post-war equivalents. The "Esso" tanker shows typical Ortho ( or possibly "Ordinary" in view of the yellow) rendition really well, the red horizonal stripe being black, the dark blue "ESSO" name being white, and the bright yellow tank body being dull grey. The red "Royal Daylight" tank is black, and the green "Power" tank a grey shade similar to the yellow of the Esso tank, athough in black and white there is little difference between the tank colours of all three.
I would say that the black and white images must have had some of their lettering retouched in white to make them visible. As photographed, their colours would have made them black and almost indistinguishable from their surroundings on the Ortho sheet film which, from other photos in the book, Hornby were clearly still using in the 1950's.
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Although I was very interested in geography, I didn't study it formally at school beyond "O" level as it didn't fit with my intention to become an engineer. However, I used to borrow the "A" level geography and geology text books from friends who were studying it, for light relief. From memory, the 1960's technique was to accurately drill vertical holes at accurately-surveyed points, and line them with plastic tubes. Periodically, glass tubes partly filled with hydrofluoric acid woud be lowered into the plastic tubes to various depths and left while the acid did its work. The angle of the boundary between the etched and non-etched glass would show the angle of the plastic tube at that depth, allowing the relative movement between different depths of soil at each location to be established, and by accurately surveying the positions of the tops of the plastic tubes, the amount of absolute movement. No doubt these days it is all done electronically.
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I have sometimes used a barge pole to control direction by using it to lever the boat round. Only at slow speeds, and care needed not to get it stuck in the mud! Also some success in deploying the pole at the bows like an oar to increase drag on the appropriate side. But only ever for short distances.
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Possibly the hire charge incliudes third party insurance? In France, I believe that the legal situation is that anyone riding, on the public highway, an electric scooter capable of speeds greater than a brisk walking pace (I think 6km/hr) is obliged to have third party insurance. How well this is enforced I have no idea.
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Grüß Gott! Thanks for a most interesting account. I wish my German was as good as your English!
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The description of what happens during charge and discharge is pretty much on all fours with the description in a 1940's specialist textbook on accumulator charging. At thst time it was common practuce to recharge accummulators from DC mains via a lamp board, the number and wattage of the lamps determining the charging current. Charging would continue untill all cells in a battery were gassing freely, meaning that all cells were able to attain a fully charged state in which even the sulphate in the deepest layers of active material would get converted. It was considered safe to discharge down to 1.8V per cell: deeper discharge would result in the production of hard crystalline sulphate having a different crystal structure to the sulphate produced at higher discharge voltages, and it is the hard sulphate that is virtually impossible to convert back. The voltage drop at high current discharges is due to the sulphuric acid reacting with the plates by giving up its sulphur; the reaction generates water which dilutes the acid near the plates and hence affects the chemical reaction that generates the current. Allowing the battery to rest allows fresh concentrated acid to diffuse into the active material, thereby raising the voltage again.
I don't think that sort of constant current charging is practiced much these days. Charging until the voltage reaches a value indicative of full charge is fine if all cells are balanced. However, the voltage of a weak cell can rise to a higher level than the other cells, thereby tricking the control circuitry into terminating the charge cycle before the other cells are fully charged.
Installing a solar charger is a good move. In a recent post of another thread the poster reported that his boat was fitted with solar panels last year, and that after several months of non-use, his batteries, which his instruments had indicated had lost a significant amount of their original capacity before the perid of non-use, were now being indicated as in good condition. Possibly the enforced period of resting had allowed the conversion of the deeper regions of the active material to be regenerated as there would have been plenty of time for the electrolyte to diffuse into the deepest sulphate layers, allowing them to become converted.
Trickle charging at a low current is known to be a good way of keeping a battery in good order, but is not practical in a canal boat whose battery is used every day. Rapid charging of really heavily discharged batteries is not recommended for ordinary batteries: the resulting high current density in the conductive regions of the plates between the higher resistance sulphated regions will give rise to differential thermal expansion between sulphated and non-sulphated regions, resulting in shedding of active plate material and loss of capacity. Trickle charging keeps the current density and temperature rise low, reducing the likelihood of shedding active material.
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I am learning Italian, and practice by reading Italian on-line newspapers. Today's "La Stampa" has a report from Milan of a collision between a hired electric scooter that swerved out of control in an underpass, colliding with a Hyundai, the scooter driver hitting the windscreen with his head before ending up on the asphalt and being taken to hospital with very serious injuries. The 8th incident in the last 48 hours and the 130th since the hire scheme started in June. It also mentions an earlier incident where a scooter going the wrong way in a one way street, knocked down an old lady, breaking her hip. She is expected to be in hospital for 3 months to recover.
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Shame about the costermongers' apostrophy!
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Apparently we (Brentwood and Shenfield) are to be one of the places to trial electric scooters. The proposed hire charge seems expensive, about £7 for 30 mins is one suggestion. The trial would include the provision of cycle lanes on key routes, something positive for us as we usually use our electric bikes for local shopping to avoid traffic and /or parking problems.
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Or have a backup when you drop one in a lock!
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I doubt that the small wheels of the scooters I have seen would be suitable for rough and/or muddy towpaths, and you would need a rucsac for your shopping.
I guess the comment on self destruction applies to the Lithium batteries that most, if not all, new models seem to be fitted with. We have had electric bikes for almost 15 years. They use sealed lead-acid batteries and can be kept for long periods without suffering damage. I don't know if any models are still available new that use lead-acid batteries. A replacement set of three 12V 12Ah traction-quality batteries with a specified 5 year life cost about £130 from electrical distributors such as Farnell, CPC and RS. I recently paid nearly £200 for a higher quality set with a 10 year specified life. Buying the same sort of thing from bike shops will probably cost you more. The estimated life times have proved to be realistic: the "5 year" set I have just replaced had lasted 7 years. If you can find a second hand model with worn out lead acid batteries, getting replacements shouldn't be a problem, but you do need to specify traction quality (suitable for golf buggys, electric wheelchairs, disability scooters etc.). Batteries designed for static uses such as emergency lighting, while much cheaper, are less robust and likely to have a short life in a bike.
I take my more than 30-year-old Bickerton folding bike (aluminium frame, designed for taking on public transport in its carrying bag, not electric) with us when we go on the canals. It only has a 12" front wheel, but that hasn't been a problem on unmetalled towpaths.
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The pitch of the old German DIN standard thread for steel electric conduits (Stahlpanzerrohrgewinde, abbreviated as PG) was defined in terms of "threads per english inch". In principle, its use in Germany was discontinued in 2001 in favour of metric conduit, however some PG fittings, such as cable glands, still seem to be widely available, even in the UK. PG has a 80° flank angle, and is a surprising omission from my copy of Machinery's "Guide to World Screw Threads" book (1970 edition). I guess it was established before metric threads became standardised by international agreements in the late Victorian era. Unlike ordinary nuts and bolts, new pipes often have to joined to old pipes. There is little point in changing for change's sake, so BSP with its Whitworth thread form remains the world standard for general purpose screwed iron pipes (other than in North America).
Another way of establishing the type of internal thread is to screw a piece of wood into the bore. It doesn't need to be perfectly circular, just small enough so that the highest parts are scored by the thread. However, as Whitworth and UNC have identical pitches in the size range of interest, wax, gum, or Plasicene would be needed to make an accurate impresion of the thread form to distinguish 55° Whitworth from 60° UNC.
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It depends how you do the charging. Some years ago when I was with Marconi I salvaged an apparently completely dead (0V) Sonnenschein 12V SLA battery from an old Inmarsat "suitcase" base station that Marconi Marine had left behind as scrap when they moved to another site. Before turning to management, our office manager had been a research chemist doing battery research and development at the old GEC Hirst research labs at Wembley, and said that, if it had died due to self discharge, it might respond to being connected to a voltage source via a high resistance. I used a 1960's 12V trickle charger that provides about 15V off- load, and a 12V 2.2W MES bulb for the current-limiting resistance. Nothing happened for several days, but eventually the bulb started to glow dimly, and got progressively brighter with time. It took a couple of weeks, but the battery was eventually restored to about 50% of its rated capacity and I was able to use it to power an electric tyre pump for my bicycle for several years before it finally died (with periodic recharging of course).
You cannot use this technique with modern smart battery chargers, as they rely on detecting a voltage in the range expected for the battery to be charged. If no volts are detected, no volts will be output as it thinks no battery has been connected. It can be a problem with very sophisticated chargers designed to automatically detect and charge 6V, 12V and 24V batteries. If you have let your 12V car battery get really flat by leaving the lights on, its terminal voltage can be in the range that the charger expects to see from a 6V battery, so it will only attempt to charge it to 6V.
I guess that, commercially, it would cost more than a battery is worth to attempt resoration of dead batteries, more cost-effective to scrap and buy new replacements, time is money. An engineer at Plessey who had been in the Royal Signals regiment said that they used to do a discharge-charge cycle on their batteries every 6 months or so to keep them in good condition, first fully discharging to a safe voltage, then recharging until all the cells gassed. The object was to reform the active material of the plates, a technique described and recommended in my old accumulator charging book. It is true that SLA batteries were not around then, and manufacturers' current instructions should be followed. Nonethless, apparently dead ones can be partially resurrected.
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The reference in the battery university site about sulphation occurring if the voltage falls below 2.05V per cell is a bit misleading. Sulphation occurs as part of the normal discharge cycle. But there is sulphation and sulphation. In a fully charged battery, the positive plates have a layer of chocolate brown lead peroxide, while the negative plates have a coating of grey spongy lead. During discharge, these progressively react with the sulphuric acid to produce areas of lead sulphate on both plates, initially at the surface and progressively deeper as discharge proceeds. The production of this type of non-crystalline lead sulphate is readily reversed on charging to regenerate the original lead peroxide and spongy lead, but only if the voltage never falls below 1.8V per cell (10.8V for a 12V battery with all cells in good condition). At 1.75V per cell, the lead sulphate becomes converted to a hard crystalline form that is dificult or impossible to be changed back to lead peroxide and spongy lead. The normal sulphate has a higher electrical resistance than the original coatings, so if an excessively high current is used to charge a deeply discharged battery, there is a risk of localised heating where the current is confined to the regions between the sulphate, leading to differential thermal expansion between the different plate materials, and consequential shedding of active material and thus loss of capacity. The old way of checking if a battery was fully charged, involved measuring the specific gravity of the acid and visually inspecting the plates, but this is not normally practical these days, especially on a canal.boat.
Information from a 1940's book that deals solely with accumulator charging. Admittedly an old book, but modern lead acid batteries must surely operate with the same fundamental chemistry and electro-chemical reactions.
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Thanks, I did wonder what happened when the tide turned. Given how busy they always were, I thought the other option of an unloaded trip to get the right way round unlikely.
Here's one of "Squires", taken mid-river from the passenger gangway of one of the replacement ferrys during the changeover period. I hadn't found out if it was possible to get up to the vehicle deck to get a better view, nothing like as good for foot passengers as the old boats, but that's progress for you. It was the last frame on my first roll of 35mm colour film (what must have been one of the last batches of the original 10 ASA Kodachrome), so it's the only colour one I have of the old boats.
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Gordon and Will Crookes from a commercial postcard. Not sure if it is the Southern landing stage with the power station behind, or the Northern with the STC works behind. Detergent foam in evidence, although the river was possibly less polluted when this was taken than it was in the early 1950's, when you sometimes used to get quite large "foambergs" thrown up by the paddles.
By 1968, when I spent the summer working at STC's works at North Woolwich and sometimes had my lunchtime sandwiches sitting by the river at their wharf, the Thames was much cleaner, with green algae growing on the embankment walls, and worm activity visible as the tide came in over the mud banks.
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I was told that some of the toilet blocks in the London docks had separate "European" and "Asian" toilets, the latter being the hole in the ground variety for the benefit of certain foreign seamen and not a type of apartheid. For some cultures, the idea of putting your bare bottom on a seat that has been sat on by someone else's bare bottom is unthinkable.
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Those alleging cruelty must be unaware of how little force is required to get and maintain a lightly-loaded barge in motion. We used to take regular canal holidays when the kids were growing up, and on one occasion I did get them to tow our boat a short distance, pointing out that they were shifting several tons all by themselves. It was to illustrate the great impact that canals had on transportation, as a horse that might only be capable of pulling a ton or so in a cart, could pull 60 or 70 tons in barges, and with no exhausting hills to slog up either. My late mother used to recall seeing horses foaming at the mouth as they hauled loaded carts up a hill in the part of North London she lived in when a young child in the early 1920's. A world apart from the effort required of a canal horse.
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Because they were side loading, they had to follow a figure-of-8 course, so ability to turn easily was pretty much a necessity. I guess the course also meant that they could always moor up facing the flow, whether ebb or flood. In the early 1950's you were normally aware of the flow by observing the large clumps of detergent foam created by the paddles when getting underweigh, but on one trip a clutch of around half a dozen empty lighters had broken free of their moorings and, carried by the flood tide, were bearing down on our ferry, which had just moored up at the South Pier. Crew members appeared wielding very long barge poles with which they fended off the lighters. While we were watching the fun, the passenger gangways were raised and after the lighters had been pushed clear, the ferry went back to the North again. Dad didn't want to wait around for the return trip, so we used the foot tunnel instead, the first time I had used it..
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Thanks for the update. I last used the ferry in the mid-1980's. The diesel boats had windows through which you could ger a rather unexciting view of the engine room, not a patch on the smell of oil and excitement of the moving cranks and eccentrics of the old steam engines.
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Pity that the rest of the season has been cancelled, we were really looking forward to another Waverly trip. I had been under the impression that paddle steamers could turn on a sixpence like the old Woolwich ferries could. I think that we had assistance to wind in London, and thanks to the above posts, now know why.
I did wonder how the Woolwich ferry was refuelled! From what I remember from looking down a ventilation shaft on one occasion in the late 1960's, coke or smokeless fuel was being used at the time. Given their width, I guess it would have taken a lot to make one capsize. As they were side loading, they needed to be manoeverable, and no doubt due to having independantly- controlled paddles, had no problem turning in the relatively narrow Thames. I do recall seeing and reading a copy of what I suppose was their licence or insurance certificate in a glass noticeboard, that said it was (only) permitted to travel between South Woolwich and North Woolwich. One of the ferry captains, who was an uncle of my best friend, used to live in the house opposite ours. I only took a few photos of the old ferrys, but did manage to make a sound recording of a crossing with my newly-acquired battery tape recorder, including a sequence in the engine room with the sounds of the telegraph bells and the engines starting up and running, as well as the sharp reports made every second or so by the massive hemp mooring ropes as they tightened after being wrapped around the bollards. Not very hi-fi, the recorder's upper frequency cutoff was only 5.5 kHz, and at present I don't have a working recorder to play the tape on, but from memory it was very much like the sound of the Waverly's engine room.
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In the 1950's dad often used to take me on the Woolwich Free Ferry in East London when it was operated by paddle boats. A visit to the viewing area of the engine room was one of the highlights of the trip. I feel sure that the paddles were operable independantly, each paddle having its own engine and bridge telegraph. They were replaced by the present diesel ferry boats, themselves about to be replaced, in the early 1960's.
We went for a trip on the Waverly a few years ago, Southend to Tower Bridge, calling at Tilbury in both directions, passing under Tower Bridge, but not stopping at Tower Pier. Gorgeous sunny weather! I was surprised at how vibration-free it was, compared with diesel-powered ships, as well as the speed. Southend pier had been damaged earlier (not by Waverly!), but they managed to patch it up just in time for Waverly to use it. We were looking forward to another trip this year.
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I totally agree, things like gas and electricity regulations are there for a purpose.
Even so, when the electricity regulations were tightened a couple of decades ago, a letter appeared in one of the IEE journals from a member whose job was to train, examine, and approve the competence to practice of trainee electricians. Under the new regulations he found he was no longer legally entitled to rewire his own house himself, because under the regulations, you had to be employed by a registered employer to be legally competent to do so. Because his college was not such a class of employer, the situation could have arisen where he could have had to get one of the former students whose competence he had checked and signed off, to check and sign off the competence of his own work.
It all depends on how the legislation is drafted. During the 1970's and 80's I was a Patent Examiner with the UK Patent Office. Under the legislation in force when I started, many of the requirements were not drafted in absolute terms, but had to be met " ... to the satisfaction of the Comptroller". Unlike what is normally perceived as civil service culture, we were not "Jobsworths", but were actively encouraged to exercise discretion in favour of the applicant ( the "Nelson" touch was definitely alive and kicking) and only concentrate on important issues: the Comptroller was often easiy satisfied! The replacement legislation was aligned with a european model in which the discretionary provisions were replaced by absolute ones, but many examiners found ways of interpreting them in discretionary ways until positively directed not to do so.
These days one of the few situations where common sense seems to be officially encouraged is in the Covid advice, and an elastic application of the rules adopted by the likes of Dominic Cummins.
Electric bike recomendations
in Boat Equipment
Posted · Edited by Ronaldo47
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A few years ago when contemplating getting one for my father-in-law, we tried out some disability scooters at a local stockist. Some were certainly nippy. The guy said they had supplied scooters to the Lakeside shopping centre in Essex, and had soon been asked to modify them to reduce their top speed to 4mph due to the number of speed-related incidents.