We did this last Sept. If you are very claustrophobic, I am not sure this would be a great choice. There are rows of benches on each side of the boat. Each bench is meant for one person and you are really close to the person on the bench beside you (you straddle the bench to look out the windows).
It had rained the morning we went so the water was not very clear.
Coral World was not really what we had expected. We have been to several large aquariums and we thought it would be more like them It is not a very big place and there was not much to see or do. They did not have a large variety of fish in the aquariums. There were a couple of places you could have "hands-on" experiences --I think the sting rays, lorikeets, and a small tank with two starfish. We did the sea lion show and it was entertaining. They had a few large sea turtles.
We didn't visit the beach.
I have seen rave reviews from others on here but it just wasn't for us.