Onewheeler

Yes, I was wary of the common statement that the Willis is usually used on a vented system. The one I am looking at is rated to 3 bar, which is adequately above our system primary pressure and the accumulator / expansion tank is plenty large enough to cope with heating up the water. Still thinking about it but there don't seem to be major issues that can't be resolved.

Wondered if anyone has experience of using an external immersion with a marine calorifier. It would be nice to use shore power, and easier to plumb on our boat than installing an Essex flange [note to moderators: that's only rude if you have a filthy mind] on the tank. Is convective circulation likely to be sufficient or would a pump be needed? Thinking of using a 1 kW heater as our shore power capacity is only 6 A. It would take a few hours to heat up a respectable volume of water but fine if on a timer for the morning shower. Martin/

Replace the bubbler fittings with a 1/4" BSP male to 12mm compression on the outlet side and a 1/4" bsp to 10mm fulham connector (or 8mm depending on what size hose you need for your regulator) on the inlet. More or less what I've just done. Use some liquid PTFE sealant on the BSP threads (Screwfix 5321J is good stuff). Ebay has all the bits: e.g. 120964642905 for the outlet. As said above, the ones fitted to the bubbler need a bit of force to undo: a good spanner and a vice are essential. Martin/

D. Ours collects a little water if we've been running hard and no-one turns a tap on. It only gets emptied at oil change time.

Mine has a little tap on the top (and the flow from the engine is a few cm below it). It is vented every couple of years when I think about it. At one time we had a BMC1.8 which let gas into the coolant, and it needed bleeding very regularly.

There was a tale, of dubious origin, that someone was prosectued (1950s or 60s?) for stealing electricity from the Brookman's Park MW station of the BBC. The talke was that he had erected a resonant antenna powering part of his house at the end of his garden adjoining the transmitter site, and the engineers noticed a "hole" in the distribution of RF energy in that direction.

2.5 L / h is high unless you're going faster than most canal speeds. On our narrowboat we use less than 2 L / h (15 T displacement, 38 HP Beta) and most of our cruising is at about 7 km / h. We're just back from our month share in a converted oil tanker on the mainland: that's 35 T with a DAF 575. From 300 km and 150 locks with 85 h of engine running, cruising mostly at about 9 km/h, we averaged 2.4 L / h. Martin/

The Snug at Carnforth is wonderful, but quite restricted opening hours. In Lancaster the canalside White Cross is (in my opinion) much nicer than the Water Witch. Excellent food. Lancaster is full of nice pubs, and there's a wheelchair-friendly slope from most of the bridges in the centre. On the Glasson arm the Mill at Conder Green is a bit smart and foody, but still a nice place for a meal or a pint. The Plough at Galgate is easily reached from the canal: food is quite good, but I always found the beer rather disappointing. The New Inn just up and over the road from it is a nice "proper" pub. They should all be wheelchair accessible. (I've never been there by boat, but the boy-child was at uni there so we visit regularly)

Google "navigation authorities". e.g. https://www.waterways.org.uk/news_campaigns/campaigns/ea_navigations/navigation_authorities

Looking at the spec sheet you might just get away without one, but my preference would be to fit one. Either find a handy piece of *flat* steel to mount it on, or buy a heatsink from RS or wherever. If the heatsink is bigger in area than the device it should have a low enough thermal resistance for your application (unless you then wrap it up i foam!) You might find a CPU heatsink that could be adapted.

It should work, my only reservation would be that it's not clear how it would like a modified square wave input. A PSW invertor should be OK. At 1 kW you'll need a heat sink, but not a big one. Let us know how you get on! It might be a useful means of running a domestic macerator toilet from an invertor.

A happy discovery: the tiller arm is a snug fit over the spout of the washbasin taps, enabling me to wield the biggest spanner on the scaled-up tap to change its washer.

Yes, it probably is, but at our normal speeds the temperature seldom goes into a region that gives me concern. Pushing against a river in flood needs a careful eye on the temperature gauge though!

The engine thermostat does not control the coolant temperature if the thermal output from the engine is too high for it to control. My engine regularly goes way above the engine thermostat temperature as most of my cruising is at 8 - 10 km/h. I'm not in the market for a thermo/pressure relief valve, but where the engine coolant could exceed 100 C without raising an alarm it could be argued that there is a case for a combined parameter valve to protect the occupants from secondary side boiling. An engine temperature warning set at an accurate level under 100 C would be more useful: I am not convinced of the accuracy of the one on our engine although it should be under 100 C. The pressure cap on the primary coolant is, according to the manual, 13 psi, which with antifreeze added could enable it to reach 124C before relieving. It therefore does not give significant protection to anything but the engine. Open to argument over whether a thermo/pressure relief valve improves safety... Martin/

We are discussing combined thermal and pressure relief valves. I've never seen one in a chandlers, or a DIY shed come to that. Lowest pressure available on a quick search is 4 bar, most are 7 bar or more.

OK! I've never come across one before but it does seem a good idea. A quick search shows nothing available at under 4 bar, which is a bit high for many calorifiers. How many boats actually have one fitted? One could tee-off a separate PRV at a lower pressure rating.

Is that not for direct feed systems only, or am I behind the times? (It would not be unusual!) Are the plastic containers indicative of where the leaks are coming from? It looks from the slightly fuzzy photo as if there is a bead of water on the tee-fitting above the white container.

I have similar, it works fine. Mine has an external shunt. Only minor grumble is that with low loads which should be within the resolution of the current metering it doesn't register. Planning to investigate further this week. It's fascinating to watch the Webasto consumption changing through its cycle.

Eek! I only paid a few tens of quids for my 1 kVA isolating tfmr. One doesn't see those prices on Ebay any more!

Not obvious at all. If you happen to make the connection at zero degrees phase the current into the transformer will be maximum. The minimal load usually connected is of minor significance.

NTC thermistor would be a cheap and nasty solution, and might do the job (assuming that 5 ohm is sufficient to avoid tripping the marina's MCB, which it might not, as it's rated at only 6A and seems quite sensitive. It's a class B so moves fairly fast. Last time I looked 6A type C MCBs were as rare and expensive as unicorn bits, even if the marina would let me put one in.) As I've got all of the bits I'll probably assemble something like figure 1 in this: http://www.edn.com/design/analog/4349191/Time-delay-relay-reduces-inrush-current I'd wondered what other people use, if anything.

I wonder if anyone has installed a soft-start on their shore power line. If I randomly connect on the wrong part of the mains phase the isolation transformer trips the shore-side MCB, which is a nuisance. I'm thinking along the lines of a big resistor at a few tens of ohms with a shorting relay and a simple time delay circuit to let the transformer field build up. Martin/

I've got a RS 181-1340 1 psi sensor waiting to be played with. 1 psi range, but it needs an op-amp interface to the Arduino as the output level only spans 30 mV.

Had started to use a pressure sensor + Arduino for monitoring the water tank level, but the sensor wasn't stable enough. Have a better quality sensor which will be developed sometime. (Unless I just use a sight tube!) Main problem is finding a sensor with sufficiently low pressure range, but they are available (the new one has a span of 100 mBar I think) I also considered using an Arduino as a rudder indicator on our shared barge, but ended up using op-amps and an analogue meter: mainly because a digital display would be too hard to read in bright sunshine.

That looks like it. It is / was free if you are dining. A nice spot although I thought the restaurant unexceptional considering their prices. It is a handy mooring as it's difficult for quite a long way above and below.