US3842784A

US3842784A - Sealed,upstanding,closed,propeller well for power boats

Info

Publication number: US3842784A
Application number: US00227033A
Authority: US
Inventors: M Nelson
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-02-17
Filing date: 1972-02-17
Publication date: 1974-10-22
Anticipated expiration: 1991-10-22

Abstract

In power boats a hole is formed near the propeller, offset from the keel, and a hollow casing, of sufficient height to reach above the water line, is sealed to the hull around the hole so that water may rise therein. A cover is detachably sealed over the upper end of the casing with a filler plate depending therefrom and removable therewith to substantially fill the hole in the bottom and avoid turbulence at high speed. The housing wall is no higher than the length of the upper arm, to permit reaching under the boat to clear a fouled propeller.

Description

lJnited States Patent [191 Nelson SEALED, UPSTANDING, CLOSED,

PROPELLER WELL FOR POWER BOATS [76] Inventor: Mellin G. Nelson, 50 Shortell Ave.,

Beverly, Mass. 01915 [22] Filed: Feb. 17, 1972 211 Appl. No.: 227,033

[52] US. Cl. ll5/.5 R, 115/34 R, 114/173 [51] Int. Cl B63h 1/28 [58] Field of Search 115/34 R, .5 R, 37, 40; 9/1 R, 6; 114/.5 R, 201 R, 203, 173, 174, 221 R, 222

[56] References Cited UNITED STATES PATENTS 1,226,699 5/1917 Saunders 115/34 R 1,754,983 4/1930 Cumbo 115/34 R 1,763,464 6/1930 Gunderson et al. 114/173 2,362,298 1l/1944 Newell ll4/173 FOREIGN PATENTS OR APPLICATIONS 575,016 3/1958 Italy 115/34 R 1 Oct. 22, 1974 Primary Examiner-Trygve M. Blix Assistant Examiner-Edward R. Kazenske Attorney, Agent, or Firm-Pearson & Pearson 57 ABSTRACT In power boats a hole is formed'near the propeller,

offset from the keel, and a hollow casing, of sufficient height to reach above thewater line, is sealed to the hull around the hole so that water may rise therein. A cover is detachably sealed over the upper end of the casing with a filler plate depending therefrom and removable therewith to substantially fill the hole in the bottom and avoid turbulence at high speed. The housing wall is no higher than the length of the upper arm, to permit reaching under the boat to clear a fouled propeller.

1 Claim, 4 Drawing Figures ME-mwumzzmm FIG =WELL HEIGHT FIG. 4.

SEALED, UPSTANDING, CLOSED, PROFELLER WELL FOR POWER BOATS BACKGROUND OF THE INVENTION It has long been known in the art of sailing to provide a sailboat with a centre board rather than a keel, the centre board being raised and lowered in an elongated, relatively high, centre board well, usually exactly on the keel line and invariably open at the top. The best keel is a deep keel, so that centre board wells have customarily been of such height and narrowness as to preclude their use for any other purpose. They have also tended to weaken the sailboat structure in requiring the cutting of keel structure to locate the centre board in the correct position.

It has usually not been considered wise to create a hole of any kind in the bottom of the hull of a power boat for the reason that, when under way at full speed in rough or calm water, a power boat hull is subject to successive impacts and considerable stress and strain. While well fastened port holes are used in the sides of power boats above the water line, and drain plug holes of small diameter are often used in the stern to draw water from the bilge by suction during travel, holes in the hull bottom below the water line have been carefully avoided in the art, not only because they might weaken the hull, but also because a deluge might occur inside the boat in the event of a leak.

DESCRIPTION OF THE PRIOR ART In U.S. Pat. No. 1,763,463 to Erickson, et al., of 1930, a hole in the hull bottom was proposed which was closed by a port hole type window, and the detachable cover was at the level of the boat bottom. The patentees apparently had mainly in mind the ability to view a propeller to determine whether it was fouled, because there is no teaching in the patent of why the receptacle surrounding the cover would keep the boat from sinking when the cover was removed.

In U.S. Pat. No. 2,364,426 to Danielson of Dec. 5, 1944, a combined sailboat and power boat is disclosed in which there is a vertically slidable shroud which can cover, or uncover, the propeller when a crank and thrust screw are turned. However, like the centre board well of a sailboat, the shroud well is so narrow, deep and filled with mechanism that it would be unusable for clearing a fouled propeller.

SUMMARY OF THE INVENTION In this invention the power boat hull is provided with a hole proximate the propeller, but offset to one side of the keel line and, since the hull usually slopes slightly upward in this location, the propeller well of the invention preferably is at an angle of about 7 from the vertical. The propeller well housing has an integral peripheral flange at the lower end, opposed by an exterior ring of like configuration, the ring and flange being tightly clamped together around the hole with the bottom therebetween and with suitable caulking so that the housing is water tight. The housing wall is preferably of rectangular cross section and of sufficient height to reach above water level, but no higher than the length of a mans upper arm. A cover is detachably sealed over the upper end of the housing, with a depending central rod carrying a horizontal filler plate flush with the hull bottom to maintain streamlining and prevent turbulence. Water rises past the filler plate up to water level, within the housing, there being a cushion of air at the top under the tightly sealed cover and the filler plate protects the cover against undue pressure at high speed and high impact.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a fragmentary side elevation, in section, of a typical power boat with a propeller well of the invention installed;

FIG. 2 is an end elevation, in section, on line 2-2 of FIG. 1;

FIG. 3 is an enlarged perspective view of a propeller well of the invention; and

FIG. 4 is a bottom perspective view from the stern of the boat showing the exterior clamping ring.

DESCRIPTION OF A PREFERRED EMBODIMENT As shown in the drawing, the propeller well 22 of the invention is designed for use at the stern 23 of a power boat 24, having at least one inboard propeller 25, propeller shaft 26, shaft support 27 and rudder 28. The boat 24 may have twin propellers, in which case two wells 22 may be used if necessary to gain access to clear the propeller, for example, of an anchor rope 29 shown in FIG. 1, fishing line, weeds, or the like. The boat 24 includes the usual hull 31, hull bottom 32, which may be sloped, as shown in FIG. 2, at 33, and a keel structure, or rib, 34 along the longitudinal centre line of the boat bottom 32, togetherwith transverse ribs, such as 35. i

The power boat 24 is intended to travel at relatively high speed, thereby subjecting the bottom 32 to considerable impact from bouncing and from wave action,

and the hull bottom 32 is streamlined as far as possible with no protuberances or recesses which would cause turbulence.

The water line of the boat is indicated at 36, although it will be understood that the boat may plane with the bow rising and may then level off when under full speed, which will change the relationship of water level to hull. In FIG. 1 and FIG. 2 the water line 36 is depicted with the boat at rest and with the weight of at least one person in the boat, as it would be when one sought to clear a fouled propeller.

In this invention a hole 38 is formed in the hull bottom 32, preferably offset from the keel rib 34'and any other parts of the frame to avoid weakening the hull, the hole 32 being about 5 to 8 inches in diameter and large enough to receive the upper arm of an average sized man. Hole 38 is located well inside the hull to avoid conflict with rudder linkages or other parts.

The propeller well 22 comprises the upstanding, hollow housing, or shell, 41 preferably of manganese bronze and having a wall 42 of predetermined height which reaches above the water line 36, for example about 10 inches, but no higher than the length of the upper arm of an average sized man. This is to enable the man to reach in the well, bend his elbow under the bottom 32 and clear the propeller.

Housing 41 includes a lower end 43 having flange means 47, in the form of bronze bolts not shown. The lower end 43 is thus tightly sealed in a water tight manner and includes caulking compound 49, so that water 51 may rise in the housing.

The housing wall 42 includes an upper rim 52 at the upper end 53 and detachable closure means 54, including a cover 55, having a groove 56 in the underside 57 thereof, the groove being filled with a yieldable, deformable gasket material 58, such as Neoprene. When cover 55 is pressed downwardly by the latching means 61, consisting of a bar 62 and a pair of

pivoted dog bolts

63 and 64 with wing nuts, the Neoprene is compressed to tightly seal the cover and form a cushion of air at 65 in the housing.

Filler means 66 is provided comprising a filler, or flush, plate 67, depending by a central rod 68 from cover 55 at the level of the exterior ring 46 of the flanging means 47. The plate 67 and the rod 68 are threaded at 69 to permit flush installation and the plate will not turn loose because it is rectangular in a rectangular ring. Plate 67 thus creates a relatively smooth and flush closure 69, aligned with the exterior face of the hull which avoids turbulence at high speed, while relieving pressure on the cover plate and maintaining the streamlining of the bottom.

As shown in FIG. 2, the propeller well 71 of the invention may be formed with a built-in tilt, or angle, from the vertical of about 7 relative to the base flange, which assists in permitting a view of the shaft and may compensate for the corresponding slope 33 of the bottom. Preferably a zinc plate 72 is affixed to the tiller plate 67 to gradually disintegrate under the battery-like action of sea water, while protecting the material of the propeller well from such disintegration. Water may seep around the edges of the plate 67 since a tight seal is not required in view of the tight cover above the water line.

I claim:

1. In combination:

a power boat having a waterline, a central keel, an inclined hull bottom on each opposite side of said keel, and a propeller aligned with said keel and extending below the rear of said hull bottom;

said hull bottom having a rectangular hole in one of said inclined hull bottoms proximate said propeller;

a propeller well comprising a well housing having an upstanding wall of predetermined height extending well above the level of said water line, having a lower end with a projecting integral flange affixed to the inside of said hull bottom and around said hole in a water tight manner and having an opening at the upper end thereof defined by a rim of said upstanding sidewall at a level well above said water line,

said upstanding wall and opening being of rectangular configuration,

a rectangular clamping ring on the outside of said hull bottom, cooperable with said integral flange and sealingly clamped thereto around the edges of said hull bottom to prevent admission of water,

said upstanding wall being vertical but the lower end thereof at said flange being inclined to conform to the incline of said hull bottom;

a rectangular cover over the opening at the upper end of said housing connected by a central rod to a rectangular filler plate at the lower end thereof, said cover, rod and plate being withdrawable as a unit,

and locking means on the upper end of said housing for locking said cover, rod and plate in position to prevent buoyancy, water pressure and hydraulic head from dislodging the same from said housing.

Claims

1. In combination: a power boat having a waterline, a central keel, an inclined hull bottom on each opposite side of said keel, and a propeller aligned with said keel and extending below the rear of said hull bottom; said hull bottom having a rectangular hole in one of said inclined hull bottoms proximate said propeller; a propeller well comprising a well housing having an upstanding wall of predetermined height extending well above the level of said water line, having a lower end with a projecting integral flange affixed to the inside of said hull bottom and around said hole in a water tight manner and having an opening at the upper end thereof defined by a rim of said upstanding sidewall at a level well above said water line, said upstanding wall and opening being of rectangular configuration, a rectangular clamping ring on the outside of said hull bottom, cooperable with said integral flange and sealingly clamped thereto around the edges of said hull bottom to prevent admission of water, said upstanding wall being vertical but the lower end thereof at said flange being inclined to conform to the incline of said hull bottom; a rectangular cover over the opening at the upper end of said housing connected by a central rod to a rectangular filler plate at the lower end thereof, said cover, rod and plate being withdrawable as a unit, and locking means on the upper end of said housing for locking said cover, rod and plate in position to prevent buoyancy, water pressure and hydraulic head from dislodging the same from said housing.