http://maps.google.ca/?ll=17.476719,...38581&t=h&z=15

You can see in the map the U-shaped causeway where the new cruise ship center is supposed to go, beside the current cargo pier (which is too small for cruise ships, and can only handle one ship at a time, so is needed for cargo). There is a channel through the reef, and if you scroll out, you can see where the ships are at anchor about 5 miles off shore, and then to the east of them is the reef.

Some conceptual drawings are at http://belizecruiseterminal.com/