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Are you insinuating that at my age I am not grown up when I am old enough to be your grandmother? Testy whippersnapper. Boaters running BTs unnecessarily are a pain in the ears and are like children with new toys.

Yes you can remove the motor from its mount with the boat in the water, just don't start removing things below the height of the motor. Just because you saw one idiot it doesn't follow that everyone with a BT is doing the same thing. Nobody has ever said that BTs are a necessity but whether it's a ship or a canal boat the principals are the same. There was a time that ships didn't have BTs and many are still built without them. Do you think there's a clique of ship captains without BTs who tell other ship captains with BTs to learn how to steer? No of course not because unlike some narrow boaters they are grown ups! 😋

Some people only see idiotic use of BTs and refuse to acknowledge that used properly they can actually be useful... 😉

Was not meant as information, it will save him a lot of money and I have never found a desperate need for a BT on an inland boat, we were not talking ships. Had an idiot go past me today where the female steerer was using the BT to steer the boat through Middlewich, every bend, every bridge. Totally unnecessary making all that terrible noise all the time.

Not very useful information to kingbilltmatt, Tracy. Strange you should get water in the forward locker at the same time as the BT failed. matty (on this post) says you can remove the motor while the boat is in the water, however this may not be of much help if the seal at the gearbox/tunnel has failed. Does the motor still run when you press the button. If it does it could be the shear pin, so read the rest of this post on how to deal with it. If the motor doesn't run then check the fuses. I agree with Ttacy, don't use the BT if you're going to suck water in from the bank side. By the way large cruise ships have bow thrusters. I'm sure the captain wouldn't want to be without it.

It depends where it's mounted in the tunnel. It doesn't have to be in the centre. Mine is on one side and very easy to access from the tunnel opening and take the retaining screws out with a screwdriver. Having the BT offset in the tunnel doesn't affect its performance. Neither does mine, but mine's a 95kgf The two semicircular plastic clips are held in with screws and then the prop comes straight off. There's a recess on the back of the prop that fits over the shear pin.

Up until 1980, when BT adopted VRSLA batteries, they used to use large open 2 volt cells as shown in the attached photo. These cells had replaceable plates, which when they failed, were cut from the group bar and a new one lead welded in it's place.

For what it is worth, BT used vaseline to dress battery connections and they were (maybe still are) the biggest user of lead acid batteries in Europe.

I got bored with rubbish radio reception and fitted a Nobsound It has line in and BT. I streamed stuff off my phone or ran it from the TV output. Worked very well just like a large BT speaker 😉 There are lots of Nobsound units on the market each slightly different 🤔

Just purely from observation on my part, during my travels for BT, the smaller telephone exchanges had Gardner or Lister engines as standby generators. These were regularly run and well maintained, with not a lot of hours on them. @cuthound will know more. I don’t know if any finished up in canal boats though.

You can but it doesn't show the improvement it does with the prop pushing water over it -- Ricky did comment on this, there's not much steerage way with no power on. TBH this is a price I'm willing to pay for better steering with power on -- since I very rarely if ever try to steer a boat with power off (I can "glide" in silence with power on...), I don't really care about this... 😉 That's just a low profile aerofoil-type rudder (NACA010?) optimised for higher-speed low-drag hulls with low rudder angles, because this is where most rudder research is targeted. For low speed and high angle applications like a narrowboat you really want a thicker profile with a blunt nose to stop the wake breaking away at large angles; the Schilling fishtail then increases lift and maximum working angle further. There is some increase in rudder drag but this is completely negligible at low speeds and compared to narrowboat hull drag and narrow/shallow water drag. The drawing I started from came from Schilling's later patent and was specifically designed for lower-speed applications where good thrust at high rudder angles is desired -- it's designed to work up to 75 degrees angle, and I can confirm that it does this. It takes a bit of getting use to because it's ingrained into most boaters minds that there's no point pushing a rudder past about 45 degrees because it doesn't really do anything, but once you realise that pushing it over even further works rather well the difference is pretty obvious. I found with it right over you could push the stern directly away from a mooring at right angle to the bank without moving forwards at all, just like a stern thruster (according to Ricky) but a lot simpler and cheaper 😉 Combined with the variable-speed BT I've found I can just move the boat sideways ("crabbing?) with no fore/aft movement, like it's being pushed by an invisible hand... 🙂 It's a standard thin aerofoil rudder, designed for good lift/drag ratio in higher-speed ships.

It sounds like they had a badly designed installation so I'm not surprised they're unhappy, and I don't think they're the only ones going by some of the ones I've seen videos/descriptions of... 😞 Don't know for sure about their BT, but if they have a Vetus Pro these are a) throttleable (PMAC motor like propulsion) and b) will run for 10mins continuously at full power, or much longer (and more quietly) at lower power levels. Though under what circumstance you'd ever want to do this beats me... OTOH if they have a conventional (and much cheaper) on-off BT screamer, it's probably toast by now... 😉

The difference between BT tubes and hull sides etc. is that the tube is often not as thick as the sides. It doesn't corrode much faster but it hasn't got the material to last as long. This is compounded by a tendency not to paint them properly ( not at all on some blackings and some boats with fixed screens cannot be got at except by removing the BT unit) and by the stresses locked into the tube by rolling it and then resistance welding the seam. Drawn tubes would be better (and could be thicker) but they are much more expensive. A final factor is that many are used close to the bank and the tube gets blasted by loose gravel, damaging any paint. N

Ok, but how many examples of baseplates, uxter plates, hull sides, etc, corroding through can we find? I'm sure there are many more than BT tunnels even if we weighted the results to take into account the fact that perhaps only 10% of narrowboats have BTs. I obviously don't have the data but anecdotally it seems like hulls are more susceptible to corroding through in other places.

I don't have an anode in my BT tunnel and 19 years from new it's still in perfect condition. Perhaps I've just been lucky, I don't know. Are they well known for corroding thorough? There may be more, but in 18 years on this forum I think I've only heard of one case. The BT tunnel should be far enough under the waterline that it doesn't suffer unduly and I'd have thought there are plenty of other parts of a hull that are far more susceptible to corrosion. I'm sure someone will start talking about cavitation around the tips the BT prop blades. Again I haven't seen that on mine, but if that happens it's a different effect and won't be ameliorated by the galvanic protection of an anode. Thinking about it, could having an anode in the tunnel cause more cavitation?

It's a legal requirement for an individual to have third party insurance "or such a security in respect of third party risks": "a person must not use a motor vehicle on a road unless there is in force in relation to the use of the vehicle by that person such a policy of insurance or such a security in respect of third party risks as complies with the requirements of this Part of this Act, and" An insurance policy simply means that in return for a premium the insurance company guarantees to pay out damages to third parties. What I believe BT did was the same, except BT -- rather than an insurance company -- accepted the risk (presumably in writing) and guaranteed to pay out damages. They were "self-insuring", which would legally have the same security as an insurance policy. Or maybe BT were actually authorised to act as an insurer? I don't know if this is still the case nowadays, but the law doesn't seem to exclude this for company-owned vehicles should a big enough company (like BT) choose to do it, though they may have to jump through some legal hoops to do it.

You could say the same for an awful lot of businesses... 😉 Insurance is only really needed to cover the risk of occasional catastrophically expensive incidents which would bankrupt the customer/company, for smaller sums it's not worth it. I know some big companies like BT self-insured cars/vans rather than paying out premiums, on the principle it was cheaper for them to pay directly than allow insurers to cream off a profit. I seem to remember the most expensive car insurance claim ever was many years ago in France, a car came off the road and landed on a railway track, which derailed and destroyed a train, which broke through a canal/river embankment and flooded a large area of the countryside including many houses and factories. I'm not sure even BT would have wanted to pick up the tab for that one... 😉

The common Daly, JK, JBD/Overkill/xiaoxiang BMS units all expose the state of the charge FETs over their coms units- UART, RS485, BT and App, CANBUS are all available, albeit not fitted to or exposed on all batteries. I haven't run across SPI or I2C, yet. All these BMS' will accept an incoming command to open and close the charge FET. There are others ( e.g. ANT-BMS ) I have not investigated The hardest part seem to be in parsing the control messages from the BMS to extract the necessary decision data (pack voltage, cell voltages, balance delta , charge current from the serial string of hex bytes that the BMS transmits in reply to an incoming hex byte string. Hard wired connections seem easier to manage than BT ones. A look round the home automation and diy solar sites will produce a bewildering quantity of information and there is plenty of C, C++ and Python code lurking. N

The longer comms cables on my boat are screened, for example from the Vetus Pro BT controller at the stern to the BT. Victron also recommend this for long cable runs in noisy environments, which is exactly what I said. The shorter ones are unscreened. If you want to charge a battery from a system with a different DC voltage on the GND terminal then you need an isolated B2B -- the case you quoted which has 2 B2B with parallel inputs (0-24V) and series outputs (0-24V and 24V-48V) needs one for the upper B2B, just like I said. Though this does raise potential balancing issues with the centre tap of the 48V battery, which I assume is connected to the series centre tap of the B2B outputs. The fact remains that this is an unusual case for a boat, and in the normal case under discussion -- 12V in to 12V out -- there's no need for isolation, or indeed any point in it. The same applies for conversion between different voltages where the low rail is a common 0V GND in all cases, which again is the most common case -- for example my boat has 12V for the generator start battery, 24V for the boat lighting etc, 48V for propulsion, all referred to 0V, and with non-isolated DC-DC converters for 24V (48V input, no 24V battery) and to trickle-charge the genny battery.