It is a jet boat because it will be operating primarily in the shallow
waters of Cheaspeak Bay and a lot of areas of interest are the thin parts.
The draft of the jet boat isn't significantly different than a prop boat
with tunnels but there is a big difference running with just a foot or two
of water under you when the first thing to strike will be spinning props
that will send you the the shipyard for haulout if they touch. The jets
will ingest a lot of oyster shells and other debris. The jet boat could
probably plow right through an oyster bar and keep right on operating
although the transducers and bottom paint would suffer.

The jets are less fuel effecient. Another way of putting this is that the
boat will burn more fuel at the same speed. We expect the cost of this fuel
to be offset by not hauling out to repair props so often and being able to
extend the working area safely into shallower waters. The jets also
contribute significantly to maneuverability since they can essentially
vector thrust in any direction.

The fins are to provide the directional stability normally contributed by
the drag of struts, props, and rudders. They also contribute to roll
damping.

--
Roger Long