I'll go with construction utility workboat. You see boats similar to
this tied up next to a barge with crane and pile driver on it. The
kind of setup that will do a little dredging, maybe building boat
ramps or docks, piers, or bulkheads, even bridges. Boats like this are
used for all sorts of odd jobs around a construction worksite. Same
with oil field service work although it's a bit small, they come in
all sizes.
If it were used by the military, it would have been some specialized
niche situation in a swamp or bayou or other protected flat water.

Rick

On Fri, 23 May 08, bw-fl wrote:
Last week, I posted a question here about this boat. The boat is now
for sale on the Orlando craigsist. Here's the link:
http://orlando.craigslist.org/boa/689767234.html
I'm still wondering what it might have been used for.