REPLACEABLE NOSE SECTION FOR A MARINE PROPULSION UNIT
A replaceable nose section for a marine propulsion unit is disclosed. The marine propulsion unit includes a lower gear case that extends into the water and includes a lower portion that includes a shaft section, a prop section, and a nose section. The shaft section defines a first volume. The nose section includes an intermediate section that includes an intermediate bulkhead that defines a second volume. A nose cone is threaded to the intermediate section and defines a third volume such that the first and third volumes are not in fluid communication.
1 . A marine propulsion unit comprising:
a lower gear case having a lower portion, the lower portion comprising:
a shaft section defining a first volume and having an aperture on a front end;
a prop section located abaft the shaft section;
a nose section located forward of said shaft section comprising:
an intermediate portion defining a second volume and having an intermediate bulkhead, said intermediate portion being engaged to said aperture; and
a nose cone defining a third volume and engaged to said intermediate portion;
wherein said first volume and said third volume are not in fluid communication.
2 . The marine propulsion unit of claim 1 wherein the lower portion is torpedo-shaped.
3 . The marine propulsion unit of claim 1 wherein the lower gear case forms a portion of a strut that extends below the hull of a marine vessel
4 . The marine propulsion unit of claim 1 wherein said intermediate portion is threadably engaged to said aperture and said nose cone is threadably engaged to said intermediate portion.
5 . The marine propulsion unit of claim 1 wherein said prop section comprises front and rear counter-rotating props.
6 . The marine propulsion unit of claim 5 wherein the front prop has three blades and a first diameter and the rear prop has four blades and a second diameter that is less than the first diameter.
7 . The marine propulsion unit of claim 6 wherein the blade area of the front prop and the blade area of the rear prop are substantially the same.
8 . The marine propulsion unit of claim 5 wherein the front prop has four blades and a first diameter and the rear prop has five blades and a second diameter that is less than the first diameter.
9 . The marine propulsion unit of claim 8 wherein the blade area of the front prop and the blade area of the rear prop are substantially the same.
10 . The marine propulsion unit of claim 5 wherein a propeller shaft anode is threadably attached to a rear prop shaft.
11 . A marine propulsion unit comprising:
a lower gear case having a lower portion, the lower portion comprising:
a shaft section having a threaded aperture on a front end;
a prop section located abaft the shaft section;
a nose section located forward of said shaft section comprising:
an intermediate portion having an intermediate bulkhead, said intermediate portion being threadably engaged to said aperture; and
a nose cone threadably engaged to said intermediate portion.
12 . The marine propulsion unit of claim 11 wherein the lower portion is torpedo-shaped.
13 . The marine propulsion unit of claim 11 wherein the lower gear case forms a portion of a strut that extends below the hull of a marine vessel.
14 . The marine propulsion unit of claim 11
15 . The marine propulsion unit of claim 11 wherein said prop section comprises inner and outer counter-rotating props.
16 . The marine propulsion unit of claim 15 wherein the front prop has three blades and a first diameter and the rear prop has four blades and a second diameter that is less than the first diameter.
17 . The marine propulsion unit of claim 16 wherein the blade area of the front prop and the blade area of the rear prop are substantially the same.
18 . The marine propulsion unit of claim 15 wherein the front prop has four blades and a first diameter and the rear prop has five blades and a second diameter that is less than the first diameter.
19 . The marine propulsion unit of claim 15 wherein a propeller shaft anode is threadably attached to a rear prop shaft.
20 . A torpedo-shaped section of a marine pod unit comprising:
a shaft section defining a first volume and having a threaded aperture on a front end;
a prop section located abaft the shaft section;
a nose section located forward of said shaft section comprising:
an intermediate portion defining a second volume and having an intermediate bulkhead, said intermediate portion being threadably engaged to said aperture; and
a nose cone defining a third volume and threadably engaged to said intermediate portion;
wherein said first volume and said third volume are not in fluid communication.