Man, I do love these boats! A friend in college, back in the 1960's, had the convertible version. White with red interior. He was as ugly as sin, but he always had a "boatload" of beautiful women riding with him. I never had that luck with my 1950 Chevy coupe!
I think the issue with the ground plane is just an odd texture that does not work well in the shadows. Maybe try Frosted Glass, which gives you a lot of tweaks to play with.
But it's a stunning rendering! Good job!
Bill G
