Ballast pile?...sure looks like it...

[liverock]

https://www.youtube.com/watch?v=MuJmrv_KF24#t=121

 

[old man]

I liked the Shark Better, looked like he was guarding the wreck.

 

[Salvor6]

Wish I was there with my Sea Hornet. I would have that shark on my stringer!

 

[Goldminer]

Richard,
That is the way reefs look in that depth of water in the Caymans. Quite typical.

 

[Jason in Enid]

Richard, That is the way reefs look in that depth of water in the Caymans. Quite typical.

Yeah, looks like patch reef to me too, although it does have that "boat shape". The video doesn't go close enough to see if it's cobbles or not.

 

[Goldminer]

Jason, if you look at the entire video, you will see exactly what the reef is made up of.