A conventional style of towboat has been used on U.S. waterways for decades,
with
steering control reliant on a triad of rudders for each screw, resulting in up
to a dozen rudders installed. This propulsion steered towboat relies on an enhanced
method of steering with engines to turn towboat, tow, and, an optional pivotal
hull slewing under the foredeck and pilothouse. The simple device of horizontally
angling fixed propulsion shafting to increase the turning moment available to the
propulsion is described, as is the expectation that no measurable propulsion loss
is expected for low angles of such horizontal deviation from the standard parallel
alignment. If the pivotal hull is included, turning force is greatly increased
even at low power settings; it should be possible to top a tow roughly within its
own length. Hull position indication is provided with a fixed arm always parallel
to the hull, and follow-up type steering is provided with a single steering lever.
An unique hull form with simple plating is described to mechanically and hydrodynamically
facilitate rapid slewing. The ability of this towboat to so direct thrust without
the drag from rudders should substantially reduce the en route power settings required,
particularly downstream, and effect a corresponding decrease in fuel consumption.
