Figure 10.—A reconstruction of inboard works of the Steam Battery, for construction of the model in the Museum of History and Technology.
For 18 years Petty did no more with the type, but finally, in July 1684, he laid down a still larger sloop with two decks and a mast standing 55 feet above her upper deck. She was named St. Michael the Archangel and is probably the design in Pepys’ Book of Miscellaneous Illustrations in Magdalene College, Cambridge, England. This vessel proved unmanageable and was a complete failure.
Figure 11.—Model lines redrawn to outside of plank to show hydrodynamic form of the Steam Battery.
Though the double canoes of the Pacific Islands were probably known to some in Europe in 1662, there is no evidence that Petty based his designs on such craft. He appears to have produced his designs spontaneously from independent observations and resulting theories. Before Petty concluded his experiments, a number of double-hull craft had been produced by others; however, some “double” craft, such as “double shallops” may have been “double-enders,” as shown by a “double-moses boat” of the 18th century and later.[16]
The use of two canoes, joined by a platform or by poles was common in colonial times; in Maryland and Virginia, dugouts so joined were used to transport tobacco down the tidal creeks to vessels’ loading. Such craft were also used as ferries. M. V. Brewington’s Chesapeake Bay Log Canoes[17] and Paul Wilstack’s Potomac Landings[18] illustrate canoes used in this manner. A catamaran galley, two round-bottom hulls, flat on the inboard side (a hull split along the centerline and the inboard faces planked up), 113 feet long and each hull a 7-foot moulded beam, 6-foot 6 inches moulded depth, and placed 13 feet apart, was proposed by Sir Sidney Smith, R.N., in the 1790’s, and built by the British Admiralty. Named Taurus, she is shown by the Admiralty draught to have been a double-ender, with cabins amidships on the platform, an iron rudder at each end (between the hulls) steered with tillers (to unship), and with a ramp at one end. The plans are undated, signed by Captain Sir Sidney Smith, and a field-carriage gun is shown at the ramp end of the boat. This, and the heavy rocker in the keels, suggests the Taurus was intended for a landing boat. No sailing rig is indicated, but tholes for 12 oars or sweeps on each side are shown. The oarsmen apparently sat on deck, or on low seats, with stretchers in hatches between each pair of tholes (Admiralty Collection of Draughts, The National Maritime Museum, Greenwich, England).
Figure 12.—General plan of the Taurus, a catamaran galley gunboat proposed by Sir Sidney Smith, R.N., to the British Admiralty in the early years of the French Revolution. From the Admiralty Collection of Draughts, National Maritime Museum, Greenwich.
Another experimenter with the double-hull type of vessel was a wealthy Scot named Patrick Miller who was particularly interested in manual propulsion of vessels, employing geared capstans to operate paddle wheels. In a letter dated June 9, 1790, Miller offered Gustav III of Sweden a design for a double-hulled 144-gun ship-of-the-line (rating as a 130-gun ship) propelled by manually operated capstans connected to a paddle wheel between the hulls. She was rigged to sail, with five masts and was to be 246 feet long, 63 feet beam, and 17 feet draft; the hulls were 16 feet apart.