Abstract: A cone clutch is made with a plurality of generally straight grooves machined into the clutch faces of the cone clutch. This allows rapid and efficient evacuation of oil from the clutch faces as the clutch face moves into contact with a mating friction surface. By simplifying the evacuation path for the oil, the operation of the cone clutch is made more predictable and consistent.

Abstract: A Hall effect rotational position sensor is mounted on a pivotable member of a marine propulsion system and a rotatable portion of the rotational position sensor is attached to a drive structure of the marine propulsion system. Relative movement between the pivotable member, such as a gimbal ring, and the drive structure, such as the outboard drive portion of the marine propulsion system, cause relative movement between the rotatable and stationary portions of the rotational position sensor. As a result, signals can be provided which are representative of the angular position between the drive structure and the pivotable member.

Abstract: A steering sensor system is provided for a marine vessel in which a rotational position sensor is attached to a guide member that rotates about the central axis of the rotor of the rotational position sensor. A pin is attached to a moveable portion of the steering actuator and slidably disposed within a slot formed in the guide member. The pin is slidably within the slot as the moveable portion of the steering actuator moves along an acuate path that does not have the same center of rotation as the rotation of the rotatable portion of the rotational position sensor. The sliding of the pin within the slot of the guide member accommodates these different radii of curvature.

Abstract: A marine drive shift mechanism includes a shift ring (200) having a chamfer zone (204) along an arcuate portion of its outer circumference facilitating ease of shifting. A stepped camming surface (222) provides step function shifting movement. Neutral positioning notches (238, 240) are provided on the clutch sleeve (18) to improve clutch sleeve (18) placement when the shift mechanism is in neutral.

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 two counter-rotating surface operating propellers (12 and 14). A planing plate (230) extends rearwardly from the drive housing (20) above the propellers (12 and 14) and pushes down on the surface of the water during initial boat acceleration to in turn lower the bow and aid in getting the boat up on plane. Right and left inclined splash plates (240 and 242) along the sides of the housing (20) extend from the torpedo portion (188) rearwardly and upwardly at an incline and meet the planing plate (230).

Abstract: A marine drive (10) has two counter-rotating surface operating propellers (12 and 14). The drive has a vertical X-dimension (254) in the range of about 13 inches to 19 inches in combination with a shaft-spacing dimension (258) in the range of about 8 inches to 15 inches in combination with a surfacing dimension .gtoreq. zero. In one embodiment, the shaft-spacing dimension is 13.5 inches, the vertical X-dimension is 16 inches, and the surfacing dimension is 2 inches.

Abstract: A surfacing marine drive has a drive housing (20) with a fore exhaust passage (230) forward of the vertical bore (26) housing the driveshaft (36), right and left exhaust passages (232 and 234) extending rearwardly from the fore exhaust passage (230) on opposite right and left sides of the vertical bore (26), and an aft exhaust passage (236) extending rearwardly from the right and left exhaust passages (232 and 234) and aft of the vertical bore (26) and discharging exhaust into dual counterrotating surface operating propellers (12 and 14).

Abstract: A marine drive (10) has a water inlet (234) on the side of the skeg (194). One or more turning vanes (261, 289) receive incoming water flow and turn and direct same forwardly and upwardly within the skeg to a torpedo nose passage (198). A flow divider (284, 285) separates incoming water flow entering the water inlet opening into upper and lower water streams each initially flowing along a first path horizontally rearwardly and then along a second curved path and then merging along a third path upwardly and forwardly in an internal water passage (196) in the skeg. Water inlet plate structure maintains desired water intake flow volume.

Abstract: A marine drive (10) has two counter-rotating surface operating propellers (12 and 14). The lower horizontal torpedo portion (188) of the housing (20) has an upper zone (276) with outer surface profiles (11T-17T) along horizontal cross-sections defining wedges with sharp leading tips (11LT-17LT) forming a sharp leading edge (278) for slicing through the water, the sharp leading tips (11LT-17LT) defining the sharp leading edge (278) defining a first line extending downwardly and rearwardly at a first angle (280) relative to vertical. The torpedo portion (188) has a lower zone (270) with outer surface profiles (1B-10B) along horizontal cross-sections defining wedges with sharp leading tips (1LT-10LT) defining a second line (272) extending downwardly and rearwardly at a second angle (274) relative to vertical.

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 two counter-rotating surface operating propellers (12 and 14). The upper end (302) of the leading edge (288) of the skeg (194) is spaced forwardly of the lower end (310) of the trailing edge (306) of the skeg (194) by a horizontal distance greater than the horizontal length of the torpedo (188), for full rudder control. The skeg (194) has a first zone (318) with outer surface profiles (12P-15P) which are continuous and define continuous skeg sidewalls (320, 322) therealong. The skeg (194) has a second zone (324) above the first zone (318) and with outer surface profiles (9P-11P) along horizontal cross-sections, which profiles are discontinuous and define skeg sidewalls with openings (192, 193) therein. The horizontal cross-sections along the second zone (324) have discontinuous gaps (332, 333, 336) therein defining a cored passage (196) within the skeg (194) communicating with the openings (192, 193) in the sidewalls (320, 322).

Abstract: A marine drive is provided with a large volume anode, about 30 cubic inches, for galvanic protection. The anode (230) is a brick-like block member tapered along each of its height, width and length dimensions. The drive housing has an anode-mounting section (232) extending rearwardly therefrom and has a downwardly opening cavity (234) of substantially the same shape and volume as the anode, and receiving the anode in nested flush relation.

Abstract: A marine drive (10) has two counter-rotating surface operating propellers (12, 14). Inner and outer concentric counter-rotating propeller shafts (40, 42) are supported by a spool assembly (38) locked and retained against rotation and against axial movement in the lower horizontal bore (28) in the torpedo (34) of the drive housing (26) by axially spaced left and right hand threads (44 and 46). A thrust bearing assembly (98) transfers thrust from the outer propeller shaft to the inner propeller shaft during rotation of the propeller shafts in opposite axial direction and is axially located between fore and aft driven gears (76 and 78). Propeller shaft sealing and bearing structure, and propeller self-centering mounting structure is provided.

Abstract: A marine drive (10) has two counter-rotating surface operating propellers (12 and 14). An upper adaptor spool (48) has a lower threaded outer portion (50) mating with a threaded portion (46) of the vertical bore (26) of the drive housing (20) and supporting the upper gear (42) for rotation about the driveshaft (36) and supporting the driveshaft (36) for rotation within the adaptor spool (48). Vertical bore structure enables assembly from above of the majority of the vertical drive train components into a one-piece unitary integrally cast housing. The vertical distance between the adaptor spool (48) and the lower bearing (118) supporting the vertical driveshaft (36) is about equal to propeller radius. The lower concentric counter-rotating propeller shafts (156, 158) are spaced from the upper input shaft (28) by a distance along the driveshaft (36) in the range of about 9 to 15 inches.