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IanD

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Posts posted by IanD

  1. 22 minutes ago, LadyG said:

    It was inexperience, when the engine seemed to be struggling, I gunned it, this welded the duvet to the prop. Never wanting to repeat this experience, i now kick the engine out of gear if i think I've picked up something, and it usually works, sometimes reversing the prop is required.

     

    Understood, reversing (and repeating several times) often clears things -- but not always especially if whatever you've picked up is big, by the time you've realised what's happened it's usually too late. It takes ages to cut a keep net off once all the hoops and mesh are tangled round the prop... 😞 

  2. 9 minutes ago, blackrose said:

     

    About 8 years ago I was moored in a small marina on the Warks Avon. A friend on another boat with a Victron combi lost all his mains electrics when his combi stopped working. We didn't know what the issue was, it worked ok when not plugged in drawing from the batteries, but he was a liveaboard without solar so it was a bit of an inconvenience for him.

     

    Eventually, we disconnected it, took it off the wall and he took it back to the place he'd bought it. I think it found it's way back to Victron who tested it and said it was fine. When he got it back we reinstalled the combi but it still didn't work with the mains plugged into the boat. He was a boating novice so he was at the point of giving up and moving back to land and I'm not an electrician so I didn't know what to do. A couple of days passed and I thought I'd plug my socket tester into one of my boat's mains sockets. It just hadn't occurred to me before that the mains supply might be faulty, but I was shocked to see about 250v - 255  on the tester.  None of my cheap Sterling equipment was affected but Victron is a bit more sophisticated and sensitive and wouldn't work at those voltages. I told the marina manager and someone came to fix it a couple of days later. 

     

    That sounds strange, most Victron gear like inverters is fine up to 270Vac input. It needs to be because if you use an IT this has 5% stepup at no-load -- with 253V input (UK limit) this gives 266V at the inverter input -- and I saw this at Uplands marina sometimes.

     

    It could be that the maximum input voltage limit was set lower than this since it's programmable...

  3. 34 minutes ago, LadyG said:

    After  the four day duvet fiasco on my first month cc, I've rarely been down the weed hatch. I tend to steer with one hand on tiller, and have the throttle in the other.

    Not sure how that helps stop getting stuff wrapped round the prop though -- some canals are just bad for it, and some boats seem more prone to pickup than others.

     

    Getting something nasty irremovably wrapped round the prop seems more like bad luck than anything else, for example the infamous Rochdale crossings last year where other boaters got multiple prop fouls including razor wire and a mattress and I got one carrier bag...

  4. 52 minutes ago, GUMPY said:

    Unless the law has changed since I retired there is no legal requirement to have any equipment PAT.

     

    The law states that you have to be able to prove that the equipment is safe and PAT has become the accepted way of doing it but there are other ways.

     

    PAT is simple and unless the law has changed recently you don't need to be qualified to do it, just competent. So why bands don't buy a tester and do it themselves has always been a mystery to me.

     

    It always struck me as a sensible idea that boats and caravans should be tested in the same way.😲

     

    There is no legal requirement, but many venues won't let you bring in your own equipment -- not just PA but also things like backline instrument amps -- unless you can provide proof of PAT testing.

     

    (yes I know this is like ATM machines, but it's what everyone calls it)

     

    We did exactly what you said (except the tester was borrowed) but it's still a PITA when you've got a lot of gear -- which we had with a 10-piece band with full PA and 6 foldback channels and lots of backline... 😞 

  5. 8 minutes ago, Alan de Enfield said:

    If you build your boat with a 12mm, 15mm or even 18mm base plate you can virtually do away with having any ballast, lower the floor and have more head room

    That does depend on what heavy bits of equipment are placed where in the boat. If there's a lot in the stern (like mine) then a heavy baseplate would make the boat too stern-heavy...

  6. 31 minutes ago, Gybe Ho said:

     

    Am I getting confused with induction and another cooking option where the energy transfer is via something fitted into the pan base?

     

     

    I am still sitting on the diesel serial-hybrid fence hence no generator decision yet. I think Travel Packs are now technically eclipsed by large lithium banks.

     

    The market does not seem to offer a sweet 6kVA 3 cylinder generator that will purr in its foredeck hutch.

     

    My reference design is a Mothership serial hybrid. This can generate 10kVA under a tugdeck up forward but requires fat cables to deliver the power at 48 volts. At my present stage of comprehending serial hybrid design I do not understand why that power cannot be delivered aft at 250v and fed into the shore inlet circuit via a double pole 240v switch.

    No, you do need a suitable pan base, but most reasonably modern pans are fine, they're designed to be induction-hob compatible -- which are not exactly a new invention.

     

    Most hybrids (including mine) use a 230Vac generator connected to one input of a Victron Quattro with the shoreline connected to the other, then normal thickness mains cables can be used for the connection even if the generator is in the bows. This allows the Quattro (controlled by the BMS) to deal with all switchover/control/charging functions, and gives a backup 230Vac source in the rare case that the Quattro inverter fails.

     

    A nominally 6kVA generator really isn't big enough by the time you consider system losses, actual continuous generator capacity, temperature heatsoak, required charging rates, and wanting to keep running times down. I'd say you need 9-10kVA depending on the generator spec, and a Quattro 48/10000 (8kW continuous output, 7kW battery charging if you can keep it cool enough).

     

    Whether this goes in the bow or stern is a matter of choice, both have advantages. You need to think how you're going to heat the boat and hot water, if you have a diesel boiler this (and a dual-coil calorifier, and the fuel tank) all need to be next to the generator (and silencers, and skin tank...) at one end or the other. My boat has everything including batteries (except BT) at the stern, others split them between bow and stern -- both work, like everything to do with boats there are pros and cons both ways.

     

    I'm not saying that hybrids are perfect or suitable for everyone, and they are more expensive -- but do offer some significant advantages in return if they meet your requirements. They'd be much more attractive in future if there were network-wide charging bollards, but unlike EVs there's no thought-through plan to make this happen any time soon... 😞 

    • Greenie 1
  7. 25 minutes ago, Gybe Ho said:

     

    I predict those Crick companies are about to have a rude awakening if they fail to comprehend what a new generation of narrowboat owners want. The first thing every narrowboating YouTuber under 50 does, when acquiring a new boat, is point out the wall to wall, floor to ceiling varnished wood look.

     

    Oakhams will survive but the others are in danger. I suspect the others actually know where the market is heading because they are in touch with the widebeam market where interior finish is defined by the expectations of young London cosmo people. They will already be planning their decor switch, by Crick 2028 the boat of the show will go to a narrowboat looking similar to the Danni and Joe example I linked to just above.

     

    I have heard this claim many times, I guess I should investigate before finalizing plans. Does the switch to induction require wholescale replacement of pans?

     

    One factor I have not mentioned is the appeal of redundancy as a future continuous cruiser. Life aboard would become primitive if the 240v invertor failed on an all electric kitchen narrowboat.

     

    This is s difficult decision. One thing I do not share with the broader narrowboat community is a fear of gas. It must be a BSS thing that sailors are not subject to.

     

    Most pans work fine with induction hobs, but not all.

     

    Redundancy is an argument for having gas, especially if you don't have an onboard generator (I do) which can provide 230Vac even if the inverter fails (with some rewiring).

     

    I don't think going electric for cooking -- hob or oven or even kettle -- makes sense on a diesel-powered boat, which is why most people don't do it and stick to gas.

     

    It does make sense on a hybrid/electric boat where you already have a huge battery bank with a lot of electrical power (big inverter) and a generator and lots of solar, because these are all needed anyway for propulsion.

     

    But this is an expensive option today (and in the near future with no charging bollards), you've got to be willing to pay a lot for the silent cruising benefits, and most people aren't (or can't).

  8. 52 minutes ago, GUMPY said:

    I wonder how many marinas have their RCD properly tested on a regular basis.

    In marinas I have visited there was a case of reverse polarity in the bollard and two RCD that worked on the test button but were way out of spec plus a final one where the test button didn't work but it tripped within spec.

    Yes I was sad enough to carry on RCD tester with me and I used it if I was going to be in the marina for a while.

     

    They should test them regularly (like appliances should be PAT tested -- a PITA for bands...) but I bet most don't.

     

    An RCD tester is a good idea for general safety testing, they also report any wiring errors which as you say are not unknown 🙂 

     

    However given that a live steel hull is going to leak far more than 30mA -- even allowing for paint! -- any shoreside RCD that isn't totally defunct or has contacts welded shut would still trip in the much-argued case above. Assuming the one on the boat doesn't trip, obviously... 😉 

  9. 16 minutes ago, Gybe Ho said:

     

    A greater technical challenge granted but best for serious cooking.

     

    I had overlooked gas hob related condensation when planning the fitout. However my dream narrow boat would incorporate an Oakham style oversized 3' x 2' glazed roof panel over the kitchen. This would be a lifting panel that could be cracked open when cooking.

     

    I was always a firm supporter of gas hobs until I got an induction one, and many chefs have found the same... 😉 

     

    The one thing they're not so good at is cooking with a wok, a 6kW gas wok burner takes some beating -- yes you can get induction wok burners, but mostly 3kW and costing more than two grand... 😞

     

    Having said that, you can get the same power with a flat-bottomed wok on a conventional induction hob, but you still get a smaller "hot area" than a big gas burner...

  10. 2 hours ago, Gybe Ho said:

     Ooo no, not at that price given the quantity involved. £30 for 8ft would equate to £3000+ for a whole shell fitout.

     

    These planks are 9" or 225mm wide, so call it 10 across with some wastage. Building trade scaffold boards are 13ft or 3.9m long. I need a hundred full length boards or more at 8ft.

     

    I will be buying in bulk from a major trade supplier in Immingham. £15 per 13ft board. That is still £1500. I have not costed out the more typical floor make up of ply finished with Amtico or other domestic laminates.

     

     

     

    I am asking the same question, does anyone know the percentage take-up of CRT winter mooring capacity?  Rural winter moorings seem like a particularly bad deal. The majority of these moorings are in the £150 to £250 per month price bracket i.e. over 50% of the going marina rate but unserviced. As you say the need to move negates the benefit.

     

    If someone has regular paid employment in Bath, Bristol or catches a London train for work, then I get the attraction of a high-band winter mooring. Otherwise? If £50 per month for a settled winter location, then maybe.

     

    Nope. I budgeted for 13kgs.

     

    I am still debating lithium bank capacity, at 9.5kWh I would consider a 240v oven. If I was specifying my kitchen in a house I would want a gas hob and electric oven. I think that is just obtainable now in a new build narrowboat though I need to calculate the monthly kWh hit during winter when in a solar deficit.

     

    Electric cooking on a boat -- oven and/or hob -- is expensive to provide the power for (and recharge the batteries), unless you're doing this anyway for a hybrid/electric boat. In which case you might as well go all-electric (which is what I did) and get rid of the gas installation, which not only needs bottles but also costs to install, needs extra ventilation and safety devices, and causes more condensation when cooking.

     

    IMHO a gas hob and electric oven is the worst of both worlds, you need both the high power electrics/recharging and gas bottles/installation.

    • Greenie 1
  11. 11 minutes ago, magnetman said:

    Its interesting that it appeared to be such a revolutionary product yet virtually all low speed Boats are currently screw driven. 

     

    Might it have been because Mr Hotchkiss was very plausible the product was in fact no good? 

     

    Too many parts and a big hole in the Boat maybe. 

     

    One of those things which in theory is amazing and does work. Cuts the weed but not the mustard. 

     

     

    And almost certainly a lot less efficient than a screw propeller, just like a paddlewheel...

  12. 2 hours ago, David Mack said:

    But I notice even Gibbo says it is a nuanced decision:

    "I therefore believe, on balance, mainly due to the extreme danger of the boat hull becoming live due to faulty wiring that it is safer to bond the transformer safety screen and chassis to the incoming shorepower earth."

    I also note that the various fault situations Gibbo considers do not include the shore side cable chafing through so that the shore side earth wire connects to the hull - not dangerous, but with the safety screen connected to the shore side earth this would negate the point of having an IT in the first place.

     

    Also that this relies on a good shoreside ground connection, which is not always guaranteed. And that the transformer actually has an interwinding shield, which many don't (there are good reasons for this). The quality of the shield ground connection on the boat is in your control, the one on shore isn't.

     

    And to quote from Gibbo's webpage:

     

    "The hull of the boat now has 230 volts on it with respect to the actual ground outside. As this current has to travel through the water to return to earth, it is far from certain (particularly in fresh water) that sufficient current will flow to blow the incoming shorepower fuse. Obviously this situation is highly dangerous. If an RCD is fitted to the shorepower then this may well trip, but again it is far from certain. It is however highly likely. "

     

    It's more than highly likely, it's damn well certain given actual values for freshwater conductivity -- which I gave but you've ignored, and presumably Gibbo didn't look up either, he just "assumed". I'm pretty sure that all UK shorepower points (in marinas and canalside) have to be fitted with an RCD for obvious safety reasons, and the current via a live hull will be way *way* bigger than needed to trip these -- and probably even big enough to trip a fuse, but this doesn't matter. Given that he got this simple fact wrong, excuse me if I don't take everything he writes as gospel... 😉 

     

    2 hours ago, nicknorman said:


    It depends on whether you are happy to presume that the boat is plugged in via a functional shore RCD. That presumption seems to be at odds with the relevant ISO and the BSS, which require (recommend, in the case of BSS) an additional RCD  on the boat despite stuff downstream of the bollard RCD being already protected. Still, it is reassuring to know that they are wrong and you as always are right.

     

    Of course there is an RCD on the boat, as ISO and BSS require/recommend 🙂

     

    Not me, Victron and other IT suppliers. I'm happy to be in the same boat (ho ho...) as thousands of other customers, using equipment designed and reviewed by experts at a reputable supplier and tested by all the certification authorities, and that they almost certainly know better than you and your guru Gibbo whose opinion -- with some basic errors in his assumptions, see above -- is that on balance it's better his/your way.

     

    But if you think Victron are wrong, I suggest you write to them and point out the error of their ways -- I'm sure they'd be grateful to know that they've sold thousands of ITs with an inbuilt safely issue that you and Gibbo have spotted but they and the regulatory bodies didn't... 😉 

  13. 2 hours ago, David Mack said:

    The Boat is a 1930s brewer's mock tudor building. It had multiple small room when I was first drinking in the area (mid 70s), with old men in flat caps drinking mild in the public bar. Since then the rooms have all been combined and a big single storey extension built on the back. I haven't been there for 3 or 4 years, but last time I visited it had very much gone up market and gastro, with corresponding prices.

    Hidden away at the bottom of the website Ts and Cs is the information that it is owned by a subsidiary of Greene King.

    Menus are available here.

     

    C de B is fine. And closer to a pub than mooring at Knowle. Next canalside pub is The Kings Arms/Cat in the Window/Canaletto/Herons Nest or whatever its called this year, below Knowle Locks, then the Black Boy, just beyond that.

     

    That's definitely changed (and not Lees!) since we were last there but that was several years ago (2016?) -- gone upmarket is an understatement...

  14. 4 minutes ago, nicknorman said:

    It does depend on which failure mode you are considering, but most of the scenarios and thus the best practice points to connecting the screen to shore earth. Best to have a plastic case, so that the question of what to connect the case to doesn’t arise. Discussed in detail here…

     

    http://www.smartgauge.co.uk/iso_wire.html

     

    Oh dear, looks like Ian got it wrong, he will have to rewire his. Or alternatively I could be that he is right and the rest of the world is wrong, so thousands of boats will have to be retired. Yes, that is much more likely.

    The thing is, they don’t need to touch the hull. Just being in a strong electric field (strong potential gradient) means that the current partially flows through them and it doesn’t take much to cause paralysis, with drowning following shortly afterwards.

    Like I said, there are thousands of boats around the world with Victron ITs in them, all wired like mine -- oh yes, and not in plastic cases for good reasons. You'd better write to Victron and tell them they've been doing it wrong all these years, and you're absolutely sure of this because a website says so.

     

    You can't get a strong electric field in the water without lots of volts on the hull, which will cause large leakage current to ground via the water and trip the RCD, either in the bollard or on the boat. At least, unless Ohm's Law was repealed when I wasn't looking... 😉

  15. 3 hours ago, Tony Brooks said:

     

    Exactly the same on my narrowboat on the Thames, but much more so if I ever went too fast on many canals. I think the stern dropping is caused by the prop pushing water away from the stern faster than it can get past the boat and into the evacuated area.

     

    By looking at the bank (piling) at the bow or a little ahead of it you will see the level rise, then fall as the boat passes that point and finally rise again as the boat passes. That is because the boat is literally bulldozing the water ahead of itself.

     

    That gives two reasons the boat on canals often have to push themselves up hill.

     

    If you are so concerned about this sort of thing, then perhaps you should think about a shallow V hull, perhaps with angled chines, so water can get around the hull easier.

    That's why more power just makes the stern squat down more in shallow water as the prop sucks water from under the boat -- a steeper hill to climb, more power used but no more speed...

  16. 15 minutes ago, Gybe Ho said:

     Ah-ha where is the palm-headslap emoji?

     

    So the counter current generated by the forward motion of a hull in a narrow waterway is a big factor particularly when the counter current has to wriggle its way past underwater weeds each side of the hull. By underwater weeds I mean growth rooted in the canal and not the hull.

    Yes but it's not the drag from weeds in the current -- on canal bed or boat -- that causes most of the drag, it's "going uphill".

  17. 8 minutes ago, MtB said:

     

    Another effect is on a wide deep waterway, observation suggests the speed of the boat is roughly the same as speed of the water flowing over the hull (and weeds). On a thin, shallow canal one observes water flowing backwards past the hull either side so this probably happens underneath too. So there will be proportionally more weed drag on a narrow shallow canal than wide/deep. 

     

    I agree though this effect will be swamped by the power is proportional to the speed cubed effect tho!

     

    An unrelated thing to consider is how long you need the boat to last. Consider your age and how many years you think you might be boating for. I dunno about you but it is pretty pointless most of us here designing a boat to last for 50 years! :) 

     

    And that's where most of the drag comes from -- for the water to flow backwards past the hull quite fast, it has to drop in level from bow to stern, this can be several inches as you can see looking at the bank. Which means the ~18ton boat is essentially having to be pushed uphill and that's what takes all the extra energy, not the surface drag which is what weed makes worse but which is low on low-speed canals anyway.

  18. 15 minutes ago, Gybe Ho said:

     

    Is it possible weed and hull performance has been overlooked in narrowboating until recently. Now there are serial hybrids cruising around with instant kW readings the dramatic increase in kW between 1.8 mph and 4 mph has become common knowledge.

     

    A ritual pastime when I was moored up on a yacht was to scrub off growth around the hull from water level to an arms length below. I won't have have a tender on my narrowboat but if the towpath switches side often enough I could scrub off 2ft of growth from the towpath.

     

    It has, but that's mainly because power goes up with speed^3, and in most canals by far the biggest source of the drag is from the narrow/shallow channels, not hull surface drag. I found I can use double the power in return for half the speed on a narrow/shallow canal like the Peak Forest compared to a wide/deep one like the Sheffield and South Yorkshire...

    • Greenie 1
  19. 5 hours ago, Ken X said:

    Don't know about duckweed and algae but the floating Pennywort at Alvechurch is thriving. Saw some at the Shirley lift Bridge as well.

    Floating Pennywort is probably the biggest hazard nowadays because it grows into massive mats really quickly, we've seen some huge ones -- this is actually one of the smaller ones... 😞 

    pennywort.jpg

    • Horror 1
  20. 19 minutes ago, IanM said:

     

    If they set off late and get to Hopwas on the first evening I would think they were doing unbelievably well!

     

    I think you meant Hopwood 😁

     

    Using Canalplan default timings possible moorings include Hopwood (1h), King's Norton Junction (not wonderful) 2h20m, Glasshouse Brewery (ditto) 2h40m, Bournville VM (ditto) 2h50m, The Vale (good) 4h, Brum (excellent) 4h30m. It all depends what time they get off and what time they want/need to stop...

     

    When I've been hiring boats with plenty of experience, hire bases are happy to get you off first with little instruction and then move on to the newbies who will need more time spent on them, because this keeps the maximum number of people happy -- but does mean a newbie might not get off until 4pm or so, or even later if there's more than one boat in this category. But it all depends on how many boats there are and how many staff, and how diligent they are with educating newbies... 😉 

     

    https://canalplan.uk/journey/21332_cp

  21. 31 minutes ago, GUMPY said:

    Reddit😂😂😂

     

    Or you could do a Google search and follow up various results including scientific papers, which are much more verbose and less easy to understand but which all come up with similar results... 😉 

     

    Any significant fault-induced voltage (big enough to even give you a mild tingle) on the boat GND/steel hull -- which is big, and submerged in quite conductive water, not deionised -- will easily give enough leakage current to trip any RCD, on shore or boat.

     

    Go on, man up and admit you were wrong... 😉 

    • Haha 1
  22. 1 hour ago, GUMPY said:

    Give me an example of a fault where having the IT on the boat is safer. 🤔

     

     

    Like I said, in an ideal world you're correct that having an IT on shore is preferable, with any screen connected to shore GND.

     

    But for all the reasons I gave, that's not practical in most cases -- not least because having a portable one means it doesn't have to be used if it's too much bother. And there's your example, because you can't avoid using a built-in IT on the boat... 😉 

     

    And if the IT is on the boat, the interwinding screen -- if there is one, which there often isn't -- should be connected to the boat GND, as should any metal case.

     

    Incidentally, you suggested earlier that if a hull went live not much current would flow due to the high resistance of water so an RCD might not trip -- well, you're wrong. According to published data typical inland fresh water resistivity in a canal/marina (clay bottom) is about 100ohm-m or lower, plug in typical narrowboat sizes and water depth and distance to bank when moored and the likely resistance to ground is a few ohms (maybe 1ohm-10ohm range depending on various factors).

     

    https://www.reddit.com/r/geophysics/comments/70dn6p/what_is_the_resistivity_of_fresh_water/

     

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