Roman navy propelled by animals instead of human rowers?

Question

I have read one brief account of military planning around the time of Roman emperor Constantine the Great (272 – 337) whereby the Roman navy's rowers could have been substituted by animals (source citation: Anon. de rebus bell. 17,1 – 2).

Do we know anything more about what animals would have been employed, what the proposed scheme was, and whether something along such lines was ever tried in war? The account mentions that the overall aim was to reduce labor cost.

UPDATE I guess I better add more details about my sources before everybody starts thinking this is some kind of joke :) The brief account occurs on p. 365 of German historian Raimund Schulz' book Feldherren, Krieger und Strategen: Krieg in der Antike von Achill bis Attila. There's a footnote pointing to the aforementioned primary Latin source as well as to this French book as secondary source: M. Reddé: Mare nostrum. Les infrastructures, le dispositif et l'histoire de la marine militaire sous l'empire romain.

And the history of warfare has known some strange war vessels indeed, such as the planned World War II air craft carrier made of pykrete (a mixture of wood pulp and ice) ...

Answer 1

What animals: Oxen

The scheme: Paddle-Wheel

Used for warfare: Unlikely ~ (No evidence exists)

The first mention of paddle wheels as a means of propulsion comes from the 4th–5th century military treatise De Rebus Bellicis (chapter XVII) you described, where the anonymous Roman author describes an ox-driven paddle-wheel warship:

"Animal power, directed by the resources on ingenuity, drives with ease and swiftness, wherever utility summons it, a warship suitable for naval combats, which, because of its enormous size, human frailty as it were prevented from being operated by the hands of men. In its hull, or hollow interior, oxen, yoked in pairs to capstans, turns wheels attached to the sides of the ship; paddles, projecting above the circumference or curved surface of the wheels, beating the water with their strokes like oar-blades as the wheels revolve, work with an amazing and ingenious effect, their action producing rapid motion. This warship, moreover, because of its own bulk and because of the machinery working inside it, joins battle with such pounding force that it easily wrecks and destroys all enemy warships coming at close quarters."

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Sources and suggested reading:

De Rebus Bellicis (anon.), chapter XVII, text edited by Robert Ireland, in: BAR International Series 63, part 2, p. 34

Answer 2

This mechanism would have had limited use in a naval vessel, because of the absence of a reversible gear drive. (The first such was invented by Filippo Bruneschelli during construction of the dome for Basilica di Santa Maria del Fiore in Florence about 1420 AD.) Changing direction without one involved unharnessing all the oxen, reversing them on the platform, and re-harnessing them. Clearly performing such a maneuver in the midst of naval combat was impracticable.

One exception to the above might have been for driving a fire-ship into an opposing fleet without risk to one's sailors.