Apparatuses for cooling exhaust components of marine engines

1. An apparatus for cooling exhaust components of a marine engine, the apparatus comprising:

an elongated exhaust conduit comprising a first end receiving hot exhaust gas from the marine engine and a second end discharging the exhaust gas; and

an elongated cooling water jacket on the exhaust conduit, wherein the cooling water jacket is configured to convey the raw cooling water along an outer surface of the exhaust conduit to thereby cool the exhaust conduit and warm the raw cooling water therein and to discharge the warmed cooling water to thereby cool the marine engine;

wherein the cooling water jacket defines first and second channels that are separate from each other;

wherein the cooling water jacket defines a chamber into which the first and second channels are configured to conduct cooling water;

wherein the chamber is located at a junction between the exhaust conduit and an exhaust manifold; and

wherein the first and second channels each taper from a location that is closer to the first end of the exhaust conduit than the second end of the exhaust conduit to a location that is closer to the second end of the exhaust conduit than the first end of the exhaust conduit.

2. The apparatus according to claim 1 , further comprising at least one seal at the junction between the exhaust conduit and the exhaust manifold.

3. The apparatus according to claim 1 , wherein the cooling water is directed into a helical flow around the exhaust conduit.

4. The apparatus according to claim 3 , wherein the helical flow occurs in the chamber.

5. The apparatus according to claim 4 , wherein the chamber has an annular shape and wherein helical flow evenly distributes cooling water in the chamber.

6. The apparatus according to claim 3 , further comprising at least one vane configured to orient the cooling water into the helical flow.

7. The apparatus according to claim 3 , comprising a first vane configured to orient flow of cooling water from the first channel into the helical flow and further comprising a second vane configured to orient flow of cooling water from the second channel into the helical flow.

8. An apparatus for cooling exhaust components of a marine engine, the apparatus comprising:

an elongated exhaust conduit comprising a first end receiving hot exhaust gas from the marine engine and a second end discharging the exhaust gas;

an elongated cooling water jacket on the exhaust conduit, wherein the cooling water jacket is configured to convey the raw cooling water along an outer surface of the exhaust conduit to thereby cool the exhaust conduit and warm the raw cooling water therein and to discharge the warmed cooling water to thereby cool the marine engine;

wherein the cooling water is oriented in a helical flow around the exhaust conduit;

at least one vane configured to orient the cooling water into the helical flow;

wherein the cooling water jacket comprises first and second channels that are separate from each other; and

a first vane configured to orient flow of cooling water from the first channel into the helical flow and further comprising a second vane configured to orient flow of cooling water from the second channel into the helical flow;

wherein the cooling water jacket defines a chamber into which the first and second channels are configured to conduct cooling water; and

wherein the first and second channels each taper from a location that is closer to the first end of the exhaust conduit than the second end of the exhaust conduit to a location that is closer to the second end of the exhaust conduit than the first end of the exhaust conduit.

9. The apparatus according to claim 8 , wherein the chamber has an annular shape and is located at a junction between the exhaust conduit and an exhaust manifold.

10. The apparatus according to claim 9 , comprising at least one seal at the junction between the exhaust conduit and the exhaust manifold.

11. The apparatus according to claim 9 , wherein the helical flow occurs in the chamber.

12. The apparatus according to claim 9 , wherein the helical flow evenly distributes cooling water in the chamber.

13. An apparatus for cooling exhaust components of a marine engine, the apparatus comprising:

a pump that is configured to pump cooling water;

an elongated exhaust conduit having a first end that is configured to receive hot exhaust gas from the marine engine and a second end that is configured to discharge the exhaust gas;

an elongated cooling water jacket on the exhaust conduit, wherein the cooling water jacket is configured to convey cooling water from the pump along an outer surface of the exhaust conduit from the second end of the exhaust conduit to the first end of the exhaust conduit to thereby cool the exhaust conduit;

wherein the cooling water jacket has first and second channels that are separate from each other, each of the first and second channels having a first end that receives the cooling water from the pump and a second end that discharges the cooling water;

wherein the first ends of the first and second channels are located closer to the second end of the exhaust conduit and wherein the second ends of the first and second channels are located closer to the first end of the exhaust conduit;

wherein the first and second channels both taper from a location that is closer to the first end of the exhaust conduit than the second end of the exhaust conduit to a location that is closer to the second end of the exhaust conduit than the second end of the exhaust conduit;

wherein the first and second channels discharge the cooling water to a chamber that is located at a junction between the exhaust conduit and an exhaust manifold that receives the exhaust gas from the marine engine; and

wherein the cooling water is oriented in a helical flow around the chamber.