Jen-in-Wellies

The replies to this topic will have an in built bias. The OP will only hear from the survivors who moored in Newark, not those who never made it out. 😱

I've used an audio spectrum analyser app on a phone to carry out a boat tacho calibration. When you put the microphone near a running engine it gives a number of peaks, one of which should correspond to the engine speed. Divide frequency in Hz by 60 to give rpm. There will be harmonic peaks showing up too at double, quadruple the frequency. At low rpm, only the double frequency harmonic may appear. Been a few years since I did this, so details may be hazy. If when you do the sums, the rpm is obviously wrong, then halve, or double it and that is probably the right number. Jen

Success! Thanks everyone, especially @jonesthenuke for the link to the proper destructions. Jenny

That is how it looks. Thanks.

Am trying to fit a diesel tank dip tube. Have cut a 25mm diameter hole in the top of the steel tank as per the destructions. Any clues as to how to get it in place? Am I right in assuming that the rubber seal ends up on the inside of the tank and the washer and nut on the outside? How do I best get this to happen? Jenny

I do have an isolation transformer, but not an Airlink one. Advantages, Doesn't have the failure modes that a galvanic isolator can have. Will redefine neutral to boat earth, so can fix incorrectly wired shore leads, or bollards. Also generators and inverters with non neutral-earth bonded outputs, if that is a concern. Disadvantages, Hummmmmmmmmmm. Makes a little bit of noise. Uses a tiny bit of power in internal losses. Some as heat, some as hummmmmmmmmmm.

Have you tested the galvanic isolator to see if it is working properly? If it is working as it should, then you don't need an isolation transformer. What make/model of galvanic isolator do you have?

If you're posh, it is more convenient for Waitrose though.

Magnets lose their magnetism and die when they exceed their Curie temperature. These magnets have obviously decided that their best chance of surviving a boat fire is to be attached to an extinguisher! 😀

AS well as looking horrible, the shutters risk catching on your clothing when walking the gunwales and putting you in the drink.

Say 1.2m x 0.7m to cover a typical bus window with some overlap for fixings. 3mm thick plate. Steel density of say 7800kg/m^3 gives a weight of 19.7kg. Heavy, but possible to lift. You have to hold this in place while doing up the fixing. Handles?. If it slips, it scratches the paint, so need rubber edging perhaps. Risk of corrosion with water wicked in to the gap between the boat side and the plate and standing for weeks on end. Especially if the paint was scratched moving a 20kg plate around. The boats I've seen with steel shutters are generally side hinged, rather than removable and I am guessing weight is a factor. Hinges welded to the shell. Often moored in the suburbs of big cities, off side at the end of some ones garden, where they provide tempting target practice for bored kids on the towpath. They look ugly; the shutters, not the kids! Jen