US1886507A - Boat - Google Patents

Description

Nov. 8, 1932.

G. G. \NEHR BOAT Original Filed July 14, 1928 Patented Nov. 8, 1932 UNITED STATES PATENT OFFICE GEORGE G. WEHR, OF PHILADELPHIA, PENNSYLVANIA BOAT Application filed July 14, 1828, Serial No. 292,669. Renewed March 16, 1932.

My invention relates to a new and useful improvement in boats and it relates more particularly to a new improvement in boats having a relatively fiat, concave bottom.

The object of my present invention is a boat capable of attaining and maintaining great speed and at the same time capable of being propelled at an efficiency suitable for both commercial as well as pleasure boats, as distinguished from purely racing boats.

A further object of my present invention is a boat which in addition to having the above qualities, will afford transverse as well as longitudinal stability and which will always ride on an even keel at practically all speeds.

For the purpose of illustrating my invention I have shown in the accompanying drawing one form thereof which is at present preferred by me, since the same has been found in practice to give satisfactory and reliable results, although it is to be understood that the various instrumentalities of which my invention consists can be variously arranged and organized and that my invention is not limited to the precise arrangement and organization of the instrumentalities as herein shown and described. In the accompanying drawing: Figure 1 represents a diagrammatic top ment.

The boat of my novel construction is provided with a concave and generally U-shape bottom 10 and a generally vertical and substantially parallel sides 11 and 12. The boat is provided with a substantially straight or flat and generally horizontal (though possibly slightly curved) bow line 13 between the two sides 11 and 12 and a corresponding substantially straight and also generally vertical stern 14.

The bottom 10 or the boat is: of generally 2 inverted U-shape having a gradually varying radius of curvature transversely thereof from bow to stern, thereby producing a gradually varying tunnel from bow to stern beneath the The side keels are designated by the numerals 16 and 17 and extend the entire length of the boat from bow to stern. The side chines 18' and 19 are substantially the same height as the center keel 15 of the boat though they do not extend the entire length of the boat but merely extend from the stern to a little over one half the length of the boat.

Thus the side keels 16 and 17 are greatest adjacent to or immediately behind the how,

as shown particularly in Figures 2 and 3 where the bottom of the boat is curved the greatest. 'From this point on the bottom of the boat is gradually flattened out towards both the bow and stern with a gradually in- 30 creasing radius of curvature.

B means of the chines of varying angle, the bottom of the boat towards the stern is gradually flattened in addition to the fiattening created by the gradually increasing radius.

The boat is propelled by either one or a plurality of semi-submerged propellers 20 mounted upon a slightly inclined propeller shaft 21 which passes through the stern at a point immediately adjacent to the bottom, whereby the lower part of the propeller, (slightly less than half of the entire propeller) will be below the bottom line of the boat, while the upper part (somewhat more than one half of the propeller) will be above the bottom and thus shielded by the stern of the boat.

By this novel construction the water is delivered to the propeller entirely beneath the boat by a generally tunnel effect. In order to afiord a shield for the spray from the upper part of the propeller 20 which is not submerged in the water, an overhanging stern extension 22 may be provided.

The direction of the boat may be controlled-by a pair of suitable rudders 23 carried by vertical rudder stems 24 positioned substantially in line with the side keel lines 16 and 17. The rudders 23 are disposed beneath the keel lines 16 and--17 and are balanced by virtue of the central pivoting thereof, as shown particularly in Figures 1 and 7. w

In boats of this inverted U-bottom'type where sufi'cient powerv is provided for propulsion in proportion 'to the weight and submergence, the hull will rise in the water as the speed is increased, until, in the relatively light high-power racing types of boat, the boat practically rides on its side keels and on its extreme stern, with. very little submergence. This raising of the hull in boats constructed heretofore, does not take place evenly as the speed is increased, there being a tendency for the bow to rise while the stern is depressed, so that the boat plows through the water, making a very considerable commotion, and being very ineflicient .until sufficient speed is attained so that the stern will rise and the boat will .proceed on a generally even keel. This to some extent limited the efficient use of boats of prior types to those having very great power in proportion to weight.

By my novel constructlon the efficiency of the boat is greatly increased under all circumstances, whether the boat is powered for racing or merely for pleasure or commercial navigation, Thus by my novel construction, the power applied in proportion to the weight, is not sufficient to raise the hull so much, out of the water as to cause the boat to ride on an inclined keel.

This feature of my invention also serves to prevent the depression of the stern when operated at relatively low speeds, and to keep generally on an even keel, fore and aft, boats traveling at relatively high speeds, in which the weight in proportion to bottom area and power available are suited for commercial purposes as distinguished from pleasure or racing craft.

i I have generally found in boats of the earlier types not enough supporting surface relative to weight tokeep the boat on an even keel and make it plane until they attain a very, considerablespeed with more power. By providing, as in my present invention, surfaces on the bottom of the boat aft, in which the arcs or radii increase, the stern is not only prevented from lowering at very low speeds, but is raised to the desired position: to-maintain the boat on a generally even keel fore and aft at a much lower speed than where these increasing arcs or radii are not provided. The increased arc of incidence aft elevates the stern even at low speeds thus preventing the'bow from rising to an un desirable extent, and presenting submerged sections much easier to advance through the water. I v

The underwater section presented not only has a decreased maximum cross-sectional one or more surfaces or semi-submergedpro- 5 pellers' 14 are used, because the hull, maintaining a general normal position fore and aft, even at low speeds or when heavily loaded, delivers from beneath the stern of the boat a practically flat sheet of water'in which these propellers act most efficiently.

The surface or semi-submerged propellers shown herein have their hubs located as close to thebottom of the boat as possible, and while the boat is lying still the weight of the hull. makes these propellers semi-submerged and in cases where load is added in the hull, the propellers are entirely submerged, but when ,boat'is in motion at low orhigh speeds they act as a surface or semi-submerged propellers; therefore, water actedupon by the propellers considered as a whole will present fewer counteracting currents and so that the opportunity for cavitation will be reduced.

As the boat passes through the water, substantially all spray is thrown inwardly, being caught in the U-shaped recess between the side keels and the center keel, considerable air also being entrapped so that the boat as it proceeds at high speedis sliding to a considerable extent on a cushion of air and spray .resu'lting T1123, well distributed positivepressure under the bottom aft of the forward waterline. v In boats of early types, as distinguished from the boat of my present invention, the

tendency of the hull is to move the water latterly, thereby tending greatly to decrease the speed of the boat not only because of energy unnecessarily used in moving the I water laterally, but because of the negative presly, the tendency being rather to move the particles downwardly and the reaction of this contributes to the lifting of the boat so ,7

that power ordinarily wasted in moving water uselessly is here to a very considerable extent utilized in elevating the hull so that the resistance of the boat to forward movement is decreased and, considering the factors of weight and speed, considerable power is saved.

The increasing are or radius of curvature adjacent the stern of the boat, presenting increasing angles of incidence to the water, as well as the aft increasing angle of incidence of the chines, as hereinabove described, materially adds to the general stability and to the improved effect of lifting the boat because the lifting is more uniform than in earlier bottom types of boats, the reaction of the water adjacent the stern tending to lift the boat being materially increased.

I am aware that the invention may be em bodied in other specific forms without departing from the spirit or essential attributes thereof, and I therefore desire the present embodiment to be considered in all respects as illustrative and not restrictive, reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

Having thus described my invention what I claim as new and desire to secure by Letters Patent, is

1. A boat hull having an inverted U-shape concave bottom between two side keels, the arcs of said concave bottom gradually increasing aft, and having side chines extending from stern towards midship presenting increasing angles of incidence to the water.

2. A boat having an inverted U-shape concave bottom bet-ween two side keels, the arcs of which gradually increase aft, side chines extending from stern towards midship presenting increasing angles of incidence to the water, and a propeller aft having the hub theredof lying above the level of the water at spee 3. A boat having an inverted U-shape concave bottom, the arcs of which increase both fore and aft from a point fore of midship, and having side chines extending from stern towards midship, presenting increasing angles of incidence to the water.

4. A boat having an inverted U-shape concave bottom, the arcs of which increase both fore and aft from a point fore of midship, and having side chines extending from stern towards midship, presenting increasing angles of incidence to the water, and a propeller aft having the hub thereof lying above the level of the water at speed.

5. A boat hull having an inverted U-shaped concave bottom, the arcs of which gradually increase both fore and aft from a point intermediate thereof, and having side chines extending from stern towards midship, presenting increasing angles of incidence to the water.

6. A boat hull having an inverted U- my hand.

GEORGE G. WEHR.

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