Underwater Lights; purpose?

You may hear that as an explanation, but I think it is the same thing as with UFO-lights under your car...

How about no other reason other than it looks cool.....

Besides just looking cool it puts on a show. Next time walking past one of these boats look down. You'll often see the fish gathering in the light. Kind of fun to watch on a slow evening.

At anchor with the under water lights on you will see all kinds of creatures coming up to see the lights. It can be pretty cool while seeing things you never seen before.
I then like to catch the bait fish with a sabiki rig. Then with the bait fish I would use a larger hook to the back of the little fish's neck and drop him to the bottom with a small weight. Something will grab it and no telling what it will be and owners/charter guess Love it!! It is a lot of fun.

BTW The Virgin Island Shark went back in water just fine, can't say much for the bait fish though.

Why does this look like the stern of "Destination Fox Harb'r Too"?

I think you nailed it.

It is and we all made nice tip$ while fishing like I described in previous post with the charter guess and owners and the use of underwater lights at night. Every one really enjoyed it.
I do not know why Blueghost made the statement about pouring beer in the water?

I think I get it, you are probably thinking the girl has a mix drink in her hand. I really do not know what she is drinking but I do know that the mate had a "No glass or breakable containers on deck" rule that she is following.

Underwater lighting can be very attractive when it is done tastefully,and in the right location. In Camden Maine,last summer, I was blinded by the display of underwater lights as I entered the harbor. I checked the GPS to make sure I wasn't in Vegas, and thought it ridiculous that people had come up to Maine to see the scenery (which includes the night sky)and turned it into Disneyworld.
A taxpaying homeowner would be denied if he tried to file a lighting plan like that, so please be courteous, and keep your lighting to a minimum. If you want to be noticed, bring a pretty boat, and you will be much appreciated.
Best,
Maldwin

Sounds like you're referring to fishing lights (halogens) not the underwater ones (below the waterline) referred to here. I've seen some real nice colored deck and bridge lights that make a boat look like a nice bordello at the dock in Nantaucket (not for cruising), but the halogens are a definite no-no at the dock.

This is what it looks like when you go the full 9-yards with underwater lighting... a photo I took of "Katara".

Three of those in a quiet harbor, and all of a sudden you might as well be on the New Jersey turnpike.
Best,
Maldwin

Your right, we where not being that smart. We should had used the gabbling hook to throw him back in the water with instead of our own bare hands. Next time...