When our boat was built, we had a rechargeable torch mounted on the bulkhead just as you come down the aft steps.
It was similar to the aircraft emergency ones you see by the emergency exits on airliners.
Looking for a replacement, I was shocked at how expensive they are. The cheapest I could find was about £60 !!! :-0
It's not rocket science, but I've "devised" a small torch which sits in a charger on the bulkhead and runs from the boats 12V battery supply.
You just come into the boat, lift the torch out of its holster and use it to find all the switches, water cocks and so on, as you move throughout the boat.
When you've finished, you just put it back in the charger and it will be charged, ready for the next time.
It's also brilliant for the dark walk back to the boat from the pub - small enough to slip in the pocket (nobody wants a giant lantern on the table in front of them whilst supping a pint).
One charge lasts about 1-1/2 to 2 hours.
I've connected it directly back to the domestic bank battery isolator switch, so its powered (charging) all the time (and protected by a small in-line fuse).
An added bonus is that it also fits in the cigar lighter on the car, so if I'm in the car it goes with me there and when I'm living on the boat, it goes on there with me.
The very neat feature I like is that when the torch is on charge, it has a little red light in the lens, which makes it easy to find when you're stumbling around half awake, at middle of the night o'clock, trying to work out whats thumping on the roof !!! - you can just see the red light in the photo above.
If anybody's interested, I bought two - am using one and have put the other on Ebay.
If it doesn't sell, some relative will get it as a present.
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=180672061253