Careful with the Cranking
Running out of fuel or losing the engine by way of filters blocked with dirty diesel is bad enough, but ending up with an engine full of water transforms a serious nuisance into a catastrophe. One can lead to the other surprisingly easily. Cooling water exits the heat exchanger via the exhaust pipe to cool and quiet the gases. If the engine is cranked over for a long time without starting, there’s no exhaust gas pumping into the pipe, but the cooling water still gets pumped round, and it’s not unusual for it to flow back into the engine. Many engines are protected against this, but by no means all. If in any doubt about whether yours is in the happy group, when a prolonged cranking session seems likely because you must bleed air out of the fuel system, shut off the cooling water seacock first, then flip it on again as soon as the engine fires up for keeps.
Spring Sparky Checks
At spring fit-out time, most of our boats have been lying damp and idle for months. If yours, like mine, is past her first flush of youth, it’s well worth spending a few hours checking electrical connections. It’s pretty mindless work, so I put on some good music, then I grab a wire stripper or at least a sharp knife, lay out the packets of terminal connectors supplied by my local chandlery and start pulling up floorboards. Once I’ve made certain of the wiring to the starter motor and back to earth, it’s the contacts in the bilge I’m after. Others may cause trouble, but it’s the guys out of sight, especially round the heel of a keel-stepped mast, that are queuing to let me down. If I’m in doubt after giving each a serious wiggle, I remake them to be certain that when the steaming light goes out in the approaches to San Francisco, it can only be the bulb that’s duff.
The Demon Inverter
More and more of us have inverters on board these days, and wonderful things they are. At the soft end of their scale, they allow us to charge PCs, iPads, phones, etc., without the need for a 12-volt adapter, but a hefty one can also accommodate drills and other mighty power draggers. Before plugging in anything serious, however, it’s worth doing the basic sums with good old “watts = volts x amps” formula. Although the inverter is delivering main power and correspondingly low amperage, you don’t get anything for nothing in this life. All the juice comes from the batteries in the end, so a 1Kw (1000 watts) hair dryer will theoretically draw about 83 amps. However, inverters are not 100% efficient so it’s safer to divide the demand by 10 rather than 12. That blow-dry is now costing the battery bank 100 amps. Even with the engine running, most alternators won’t get anywhere near that, so it’s downhill all the way. No problem, so long as you’ve a big battery bank and you don’t run the fan heater until the lights go dim!
Stars to Steer By
A celestial navigation student of mine showed up recently with a new Plath sextant, and I have to say I have never seen so fine an instrument. It wasn’t as beautiful as the brass-bound WWII Husun that has served me well for 40 years, but it had one colossal advantage. Attachable to the optics was a black box which worked like an airman’s bubble sextant. To work conventionally, a sextant needs a clear horizon, but this device enables the user to take a sight without one. Freed from this essential factor, my student had plotted the position of his back garden in Switzerland. The real wonder is that the navigator can shoot a star without referring to a horizon. The rest of us need a horizon to make an angle to measure the star’s height, so they can only be made at twilight. With the black box, deep-space observations are no longer confined to twilight. The sheer romance of a sighting of Polaris for latitude, crossed with Jupiter and fixed by Sirius while the Milky Way blazes across an ocean sky, is enough to bring a tear to the eye.
March 2024