Tuesday, February 10, 2009


GaugesLady Jane's main engine, a 6 cylinder Industrie, is dripping with all kinds of gauges for both pressures and temperatures.

Each cylinder has both a cylinder head temperature gauge and an exhaust temperature gauge. Some of the exhaust temperature gauges have stopped working, but the cylinder head ones are all working just fine.

It turns out that the cylinder head gauges are replacements for the original, beautiful, brass Industrie temperature gauges. The originals were apparently stolen while Lady Jane was laid up in Ireland, amongst other brass fittings.

The pressure gauges you see in the picture are, from the top left, labelled as: Freshwater, Turbo, Saltwater, Oil and air.

In reality, the pressure gages are, from the top left, Disconnected, Turbo, Freshwater, Air and Oil. I'm so used to it now that it seems normal to me!

The oil pressure gauge is also repeated in the wheelhouse.

To be honest, I don't really trust the readings on any of the pressure gauges, and only really go by their relative positions compared to what I've seen them read before.

It turns out that replacing them is not as easy as it would first seem, and expensive, which is why I started down the line of the electronic engine monitor that I've been working on.

The first electronic pressure gauge on the list to get implemented will be the oil pressure gauge. With that working well, the rest should be relatively straightforward.

I'm planning on implementing these pressure gauges in addition to the existing ones, not as replacements for them, so if all else fails I've not lost anything.


  1. Anonymous7:01 PM

    Hi Tim, Have you figured out what you will use for pressure sensors at all? My personal inclination would be to find automotive oil pressure and/or turbo boost sensors and then build some A/D magic around that. I might even be tempted to take that route for fluid temperatures as well.

    A trip to a breaker's yard with 10 quid in your hand should net you a selection of oil pressure and coolant temperature senders to experiment with.

  2. With your electronic skills have you ever thought of building a few Piezo transponders and a wave form generator to negate your need for antifoul? it doesn`t seem to difficult? The right hertz range and and adequate number of transponders and your gold "teef" will be clean for ever? joking apart, have youi?

  3. Hi Anonymous

    I've just bought a brand new pressure sensor - more on this soon.

    My thinking being, I'd rather buy a new sensor as I'd have the right spec sheet for it, it's exactly the pressure I need and I'd know it was very likely working properly.

    Oh yes, and I'd readily get more in the same range, so the sensors would match.

    In terms of temperature sensors, I'll wait & see if the temperature sensors I've been working on prove to be any good.



  4. Hi Rob

    I've not thought about that at all.

    I'll need to finish a few of my other electronics projects before I look into that.



  5. Anonymous2:37 PM

    I'm curious what is the projected cost of replacing any/all of the gauges? They look like fairly standard panel mount ones from the picture. I would think you'd want operating gauges, even if you get the fill electronic setup in place. I did only the quickest search, but http://www.omega.com/pptst/PGP.html
    has what look to be serviceable gauges in the ranges you'd need.

  6. Hi Anonymous

    Thanks for that.

    From the research I've been doing on replacing the gauges, it's not so clear cut as to which gauges to get - I get different stories depending on who I speak to.

    The engine vibration points to, more expensive, oil filled gauges.

    I'm thinking the electronic senders will end up being £100.00 or so each, with any replacement gauges probably costing a similar amount.

    My thoughts are to see what pressures the new electronic versions were giving and then decide if the corresponding gauges needed replacing or not.

    To my mind, I would prefer to have access to the engine 'numbers' anywhere on the boat's network, so kind of need to get the electronic sensors anyway.

    There is no question that proper analogue gauges must also be in place, it's just a matter of being selective as to which ones actually need replacing.



  7. Anonymous4:10 PM

    I agree that new known-good sensors are the thing. But still automotive parts are going to be easier to find and cheaper than specialty parts. When you're anchored off Malaga, you will be able to pop into town and score a Renault coolant sensor from a local dealer for 12 quid, but try that with some sort of fancy-pants industrial or scientific part.

    Anyhow, eager to read about all the details. Hope to see them soon.

  8. Hi Anonymous

    Good point, and one taken on board (so to speak).

    Maybe a new ubiquitous Toyota Land Cruiser sensor would be the thing to go for?