As you saw from the photos, the water taxis aren't really ferries in the accepted sense of the word -- just open boats with a couple of outboards.
They do fit an amazing amount of luggage in these boats, and despite the anarchic appearance of things at the Marine Terminal, people and luggage do get on and off at the right places.
If you have some extra time, walk a block or so (in the opposite direction from the Swing Bridge) to the Image Factory, one of the top galleries for art, and crafts, in the region.
A taxi from the international airport to the Marine Terminal is US$20.
--Lan Sluder www.belizefirst.com