The Texas Star was built in 1977 on a multi-purpose supply ship hull, probably to service offshore oil platforms. The vessel was refitted as a floating casino in 1986, originally named Millionaire’s Casino, out of Savannah Georgia, but later moved to Texas and renamed Texas Star Casino. "The 12,000 square-foot vessel featured games such as craps, blackjack, roulette, poker and slot machines, with a bingo parlor situated on the nearby dock."
By well-lit, what I mean is situations that fall within the normal range of your camera's exposure program. This is a combination of ISO (film) speed, shutter speed, and aperture which will result in capturing a desired image. On land, such situations occur all day long, but underwater they are rare. Clear shallow water with a bright sun shining overhead is the only environment in which your camera is likely to work unaided, as it would topside.
An unremarkable ambient light test shot, at a depth of about 100 ft. Note the loss of colors, even close-up. Flash would bring out all the hidden colors.