US2217295A

US2217295A - Cooling of propeller-shaft sterntube bearings

Info

Publication number: US2217295A
Application number: US324783A
Authority: US
Inventors: Scott-Paine Hubert
Original assignee: Individual
Current assignee: Individual
Priority date: 1939-03-09
Filing date: 1940-03-19
Publication date: 1940-10-08
Anticipated expiration: 1957-10-08

Description

COOLING 0F PBOPELLER-SHAFT STERN-TUBE BEARINGS E m A T T O C 5 H Filed March 19, 19%

Patented Oct. 8, 1940 UNITED STATES COOLING 0F PROPELLER-SHAFT STERN TUBE BEARINGS Hubert Scott-Paine, Hythe, Southampton, England Application March 19, 1940, Serial No. 324,783

In Great Britain March 9, 1939 l 1 Claim.

The invention is for improvements in or relating to the cooling of stern-tube bearings for boats, and particularly for small high-speed motor boats.

The high rate of revolution of the propeller shaft in small high-speed boats makes cooling of the propeller-shaft stern tube important, and it is important also that any cooling means should be of simple and compact construction.

My prior specification Serial No. 269,019 describes cooling means for a propeller-shaft stern tube in which water, for cooling and lubricating the bearing is circulated through the bearing between the shaft and the tube from a submerged inlet, by the movement of the boat through the water. i

The present invention comprises a combination with a high-speed boat of a stern tube having an aft end portion spaced from the propeller shaft, a bearing for the propeller shaft in the for ward portion of the stern tube, a water jacket surrounding the stern tube in the locality of the bearing, a scoop on the bottom of the boat arranged to face forwardly, an inlet conduit connecting the scoop with the jacket, and an outlet conduit connecting the jacket with the aft end portion of the stern tube.

The aft end portion of the stern tube may be open to the water along its lower side, for which purpose it may be tunnel-shaped.

The jacket may extend along a part of the aft end portion of the stern tube, in which case the outlet conduit may connect that part of the jacket which is disposed aft of the bearing with that part of the aft end portion of the stern tube which is disposed aft of the jacket.

The following is a description of a stern tube and bearing arranged for a small high-speed boat, reference being made to the accompanying drawing, in which:

Figure l is a vertical section along the length of the stern tube;

Figure 2 is a section on the line 22 of Figure l, and

Figure 3 is an under-plan, on an enlarged scale, of the scoop.

The stern tube is arranged in the usual position on the bottom of the inside of the boat sloping downwardly from its forward end. The tube is provided at its aft end with a tunnel-shaped portion and with a cylindrical portion 2| near its forward and upper end having a recess 22 of smaller diameter than the remainder, which recess contains a white metal or other journal bearing 23. The tunnel-shaped part 20 is of such a size as to be spaced away from the propeller shaft.

' The cylindrical portion Zlof the tube has, cast integrally with it, a cooling jacket 24 which extends from the front end of the journal bearing to a position past the rear end so as to be half as long again as the bearing, and this jacket is, when viewed on a cross-section transversely of the bearing, of substantially semi-circular form extending symmetrically circumferentially of the tube over the upper part. A part 26 of the tube, half-way along the length of the bearing, is, however, formed solid, and a hole 27 is drilled through this part of" the tube and through the white metal bearing to serve as an inlet for the supply of grease to the bearing.

Circulation of water through the jacket is effected by a forwardly-facing scoop 28 which is screwed on the outside of the bottom of the boat to one side of the stern tube and which is connected to a copper inlet pipe 3%] by means of a joint tube of rubber Bl or other similar resilient material. The copper inlet pipe is attached by a coupling to a hollow plug 33 in an inlet formed in the jacket diametrically opposite to the grease inlet.

An outlet 34 for the water from the jacket is situated at the top of, and at the aft end of, the jacket. A boss 35 formed at this point is internally threaded at 36 to receive an externally threaded part of a control cock 40 which is secured to an outlet pipe 31. The outlet pipe is connected to a similar boss 3% formed on the stern tube about half-way between the lower end of the bearing and the lower end of the tube by means of a screw plug and coupling 39. The scoop 28 is made of suitable sea-water resisting material and is fitted by wood screws ill in a watertight manner to the bottom of the boat so as normally to be submerged.

When the boat is in motion, water is forced into the scoop and through the copper inlet pipe into the jacket formed round the stern tube, and then passes out at the lower end of the jacket at the top thereof and is discharged into the top of the stern tube at a position aft of the jacket; thus, the cooling water is employed to cool the greaselubricated bearing at the forward part of the tube and also to cool the after end of the propeller shaft itself.

The shape and size of the scoop or scoops will be such as to extract a substantial flow of sea water for a given minimum speed of the boat, so that at higher speeds of revolution of the shaft corresponding to greater speeds of the boat, a greater supply of cooling water is circulated.

Thus, the apparatus described provides an efficient means for cooling the stern tube-bearing Which also satisfies the requirements of simplicity and compactness necessitated by a small boat.

I claim:

For use in combination with the propeller shaft of a high-speed boat, a stern tube having a tunnel-shaped aft end portion spaced from the propeller shaft and open to the water along its lower side, a bearing for the propeller shaft in the for Ward portion of said stern tube, a water-jacket surrounding said stern tube in the locality of said bearing and extending along a part of the portion of the stern tube which is aft of said bearing, an inlet conduit connected to that part of said waterjacket which surrounds the stern tube in the vicinity of said bearing, and an outlet conduit connecting that part of said water-jacket which is disposed aft of said bearing with that part of the tunnel-shaped portion of the stern tube which is disposed aft of said jacket.

HUBERT SCOTT-PAINE.