What might be a simple job on a car engine can become a real swine on a boat. Today I drained down the engine coolant and refilled with fesh antifreeze mixture. Just a matter of draining the water off from the bottom and refilling from the top. Except that in a boat engine compartment, the bottom of the "radiator" or the skin cooling tank is actually right on the floor of the boat, so there is no nice spot for the water to "fall" into for a receptacle. No drain tap either so you have to undo a hose. Then how do you catch over four gallons of water gushing from a hose in a very confined space? Answer: with great difficulty.
I use an oil drain can with a hole in the side. But one small enough to get into the space would only hold 6 litres so as it filled I had periodically to somehow stem the flow, without a tap remember, and decant the drain can into a larger receptacle. About 6 times including a bit of flushing.
Actually I was quite pleased in the end that only about two or three pints spilt over into the bilge - easily mopped up with a sawn off plastic milk bottle.
Refilling was straighforward enough, helped by a bleed tap on top of the "radiator" to let off trapped air. Whether I have still got any air locks. I probably won't find out till we next cruise for half an hour.
Cost: nearly 30 quid's worth of antifreeze - supposed to last 5 years.
I just got a quote for three new domestic batteries - £69 each. That's the cheapest I can find. It appears that the rising cost of lead has pushed them up. You could get them for about £55 a few months back.