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Scholar Gypsy

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Everything posted by Scholar Gypsy

  1. Also important to understand how many thermostats you have on your engine (most have 1, but some have 2 and some have none!) and how they control (if at all) the flow to the calorifier circuit. For example on mine the coolant just goes around the calorifier circuit until that is heated up, and then (at 82 deg C) the thermostat opens and water also flows through the skin tank. If the engine is not running hard then it takes a bit longer for the hot water tank to heat up, but it still gets to the same temperature, as controlled by the engine thermostat. As others have said not all boats are the same.
  2. I think I must be quite lucky with my setup (or else it was just well designed!). There are no bleeding points on the skin tank, or for the calorifier. After draining the entire system ( a few years ago now) I just filled it up with coolant, started the engine, and off we went. It bled itself over the next hour or so, and the level was a little lower the following morning.
  3. Slightly tangential. I have added a drain point to a low point (as it happens on the calorifier return circuit) and this enables me to drain all the water in the top half of the engine and the hoses, just by gravity. Handy for changing thermostat or replacing any hoses (as I have done recently). If I need to drain the skin tank then a pela pump does it (eventually!), but as others have noted other pumps will do it well.
  4. Or you could start from Liverpool, or Ellesmere Port. Some nice shots of the Mersey in this week's "Saving lives at sea" (BBC2). Also a rather hairy rescue near Tobermory.
  5. Thanks again to all for their advice, and history on the making of pipe joints. I bought a BSPT to NPT adaptor, and a new sensor and gauge (VDO). In the end I was able to remove the old sensor while leaving the existing adaptor in the engine block, and I was able to satisfy myself (using the redundant adaptor) that the old and new sensors were both NPT. A bit of PTFE and some crimping, and I am now getting over 4 bars. It will be interesting to see again how this drops as the engine warms up. I also have a bit of kitchen towel in place, to check that the joint is not leaking. Also very pleasing that the buzzer (the other sensor) comes on exactly as the needle gets down to zero - I've never had that before.
  6. Thank you, I have found a BSPT (taper) to NPT adapter, and a NPT sender, so I hope that will work.... I am assuming that the hole in the control panel is a standard size - they do all seem to be 52mm...
  7. Thank you, that is helpful. Who was it who said "the good thing about standards is that there are so many of them" ...?
  8. I have two oil pressure sensors on my engine (Mitsubishi K4). The further one in this picture is the low pressure alarm, and this works fine (gets tested every time I stop and start the engine). And when I change the oil it beeps for a couple of seconds as the new oil is picked up by the pump and gets to the sensor -- all as normal. The nearer one is connected to a standard sized dial on the control panel, and this has been behaving rather sluggishly for a few months. I don't think I have a substantive problem with the oil pressure, so I am planning to replace the sensor and the dial with a new pair. (I also grounded the sensor wire, and the gauge flipped over to maximum pressure, so I think the circuit is OK - I had been about to check the connector plugs...) So my question is: is the threaded hole in the engine block a standard size? The parts list for engine also includes a couple of plugs for these holes (I guess in case they are not in use) which are labelled "PLUG, taper (PT-1/8)". I can find quite a few sensors on the internet, labelled 1/8" NPT, and as far as I can see PT and NPT are not quite the same (pipe thread and national pipe thread). It may be that there is an adaptor between the engine block and the sensor. So do I need a PT to NPT adaptor and then an NPT sensor ?? Many thanks for reading this far ....
  9. Yes, it's the same bus, goes Peterborough to Northampton. I guess it depends where you want to get to eventually, also I had never been to Corby before....
  10. Ely, an easy walk to Cathedral Marina and Bridge Boats (who have a large hire fleet too). Littleport, also an easy walk to the marina there. Oundle, train to Corby and then a regular bus service from there.
  11. The Boston arrangements have changed slightly since this notice. I got this updated dated 2nd August. Update on 02/08/2021: Apologies for yet another short notice update. However I hope this is a welcome one! No sooner had we agreed within the team that we could shorten the summer notice period from 5 days to 3, they have come up with an additional solution to reduce booked passage at Boston to 2 days. As the navigation authority we retain the right to refuse or cancel passage where necessary to do so. However we aim to adhere to 2 day notice periods as far as possible. Therefore please give at least 2 days notice for passage through Boston Lock. Our Lock keeper remains well placed to advise on tidal passage.
  12. That's a good photo - not seen that before. I think that bridge is just behind me in this photo ...
  13. You have forgotten about Fenny Compton tunnel, about 1100 yards long I think ...
  14. Don't forget Reach, near Cambridge http://www.reach-village.co.uk/history.html
  15. Yes, that's why I use bow and stern lines when going up, even when single handed. I think Castle Mill must depend on the design & size of the boat. With mine the flow pulls the boat sideways into the middle of the lock. OK if you are on your own, but not very pleasant if you are sharing with something plastic.... You are right the floods can be quite something, and indeed can submerge the lock completely!
  16. You should try the Bedford Ouse, where: 4 locks have mitre gates top and bottom (Roxton, Barford, Willington, Castle Mill - all built relatively recently) 8 locks have mitre gates at the bottom and a guillotine at the top (Hemingford, Houghton, Godmanchester, Brampton, Offord, Eaton Socon, Cardington, Bedford) 2 locks have a guillotine at the bottom and mitre gates at the top (St Ives, St Neots) 1 lock has a guillotine at each end (Brownshill) All the mitre gates have a slacker (paddle) each (except Castle Mill, below, which has a rather unusual slacker arrangement). It certainly keeps you on your toes....
  17. The kink in Braunston is 400m from the eastern end. I have this at the back, a bit Heath Robinsonish but it works well; and a low power light at the bows (just so an oncoming boat can see where the bows are).
  18. I had a fun conversation this year with the owner of this boat. The engine (air cooled, Lister I think) is in the bow locker (lid open for added cooling ...) and drives the prop via a hydraulic pump. The owner said it worked very well, and was quiet (at the stern!)
  19. The last wide beam I steered, the hydraulic steering was connected back to front. So in my mind I had to imagine the top of the wheel was like a tiller. We discovered this on entering the tidal Thames just downstream of Limehouse .... No harm done.
  20. Tangential point. I had a very slow leak on one of my engine hoses recently. It was fine when cold, I pumped the pressure tested up to 15 psi and it stayed there for hours. But when it heated up the hose leaked a little bit (15ml a day sort of amount, really annoying). I've now replaced it (and added some lagging to stop it rubbing against the exhaust manifold!).
  21. When I hired a boat on the Skegness canal a couple of years ago, they told me to drive on the left.
  22. Calculus is the obvious way of doing this. Using the notation of the video, the integral of y^2 (from 0 to h) is 2/3 x h x the integral of y on the same interval. But one can prove this result using pure geometry. For any triangle, join each vertex to the mid point of the opposite side. The three lines you get all intersect at a common point (called the centroid), which is the balancing point (centre of gravity) of the triangle. Also, the centroid is 2/3 of the way along the line from the vertex to the opposite mid point. From this one can deduce that the centre of action of the force on a lock gate is 2/3 of the depth of the gate - the two problems are related. (Imagine a right angle triangle with the 90 degrees at water level and the other two corners at the two bottom corners of the gate). For a proof of the centroid theorem see here: http://ceemrr.com/Geometry2/TriangleCenters/TriangleCenters_print.html https://en.wikipedia.org/wiki/Centroid Wikpiedia is rather unclear whether this result was found by Euclid or Archimedes, or three hundred years later by someone called Heron
  23. Cider is no good. You need to use canal water as it will have the correct surface tension. Another of way of thinking about how the force does not depend on the length of the pound is to imagine inserting a very light plastic gate G across the canal, at any arbitrary position. This divides the canal into two, a section one side of the gate (A) and a section the other side (B). In a static situation, the net force on the gate is zero, which means that the sideways pressure from the body A on the gate is exactly equal and opposite to the sideways pressure of the body of water B on the gate. Both are obviously independent of the shapes of A and B (as both A and B can be varied independently, and F(A) = -F(B) always). Now if you remove the water in A you have the sideways force on the gate (if the plastic is strong enough...) PS the centre of action of the force is 2/3 of the way down the gate.
  24. I've been on Swiss TV. Does that count? https://www.rts.ch/play/tv/19h30/video/jubile-de-diamant-de-la-reine-elisabeth-ii-le-point-dorgue-des-festivites-se-tiendra-dimanche-avec-une-parade-de-mille-navires-sur-la-tamise?urn=urn:rts:video:4036657
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