Abstract: A drain system is provided for a marine vessel in which three types of drain operations can be performed at one common location near the transom of the marine vessel. A multiple conduit structure is provided with a plurality of fluid passages extending at least partially through its structure. A first fluid passage allows the bilge of the boat to be drained. A second fluid passage allows multiple locations on the engine to be drained through a common port. A second sealing plug is provided to close the second passageway that prevents fluid communication between the various fluid conduits used to drain the cooling water of the engine. A third fluid passage is provided through the multiple conduit structure to allow lubricating oil to be drained from the engine.

Abstract: A marine propulsion system with counter-rotating propellers is provided with the capability of causing the propellers to rotate at different speeds. A first gear is attached to an inner propeller shaft and a second gear is attached to an outer propeller shaft. The inner and outer propeller shafts are arranged in coaxial and concentric relation for rotation about an axis of rotation. A driveshaft is connected to a pinion gear which engages the teeth of the fore and aft gears at different effective diameters. The pinion gear meshes with a first plurality of gear teeth on a beveled surface of the fore gear while a second set of gear teeth of the pinion gear mesh with a second plurality of gear teeth on a beveled surface of the aft gear. Because of the different effective diameters of the first and second pluralities of gear teeth, the inner and outer shafts rotate at different speeds.

Abstract: A marine drive (10, 310) has two counter-rotating propellers (12 and 14, 312 and 314). Inner and outer concentric counter-rotating propeller shafts (40 and 42, 340 and 338) are supported by a spool (38, 336) in the lower horizontal bore (28, 328). Passages are provided in the housing for communicating lubrication and/or exhaust with the horizontal bore. Locking structure (50, 404) holds the driven gears and bearings in place in the lower horizontal bore.

Abstract: A marine drive (10, 310) has two counter-rotating propellers (12 and 14, 312 and 314). Inner and outer concentric counter-rotating propeller shafts (40 and 42, 340 and 338) are supported by a spool (38, 336) in the lower horizontal bore (28, 328). Passages are provided in the housing for communicating lubrication and/or exhaust with the horizontal bore. Locking structure (50, 404) holds the driven gears and bearings in place in the lower horizontal bore.

Abstract: A marine drive (10) has a spool (36) positioned in the lower horizonal bore (28) and supporting a dual propeller shaft assembly (38, 40). An exhaust passage (130) includes a passage (132) in the drive housing (26) communicating with the horizontal bore (28) at the spool (36), and a spool exhaust passage (134) passing exhaust rearwardly through the spool to the propeller through-hub exhaust passages (136, 138), providing through-hub exhaust through dual propellers (12, 14). An oil passage (152) in the housing (26) communicates with the horizontal bore (28) forwardly of the exhaust passage (132) and lubricates the dual propeller shaft assembly.