Patent Publication Number: US-4652245-A

Title: Shallow draft boat

Description:
This application is a continuation of application Ser. No. 629,087, filed July 9, 1984, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to boat hulls of the kind having a screw propeller located amidship and an open bottom channel or trough, and an arrangement to produce uplifting forces facilitating shallow draft travel and maneuverability with the boat. 
     2. Description of the Prior Art 
     Man has traversed the waterways and oceans of the world virtually since the dawn of recorded history. Such as been accomplished for a multitude of purposes, including fishing, commerce and travel; and in virtually all instances, boats of various types and constructions have been employed. As a consequence, the boat building art is extremely old and well developed. 
     The most typical example of small powered boats of this century include an elongated hull presenting a bow and a stern, along with a rotatable propeller positioned at the stern of the boat below the normal water line. The propeller is rotatable through the medium of a motor, which may be of the outboard or inboard type. While this type of boat is extremely common, it presents a number of problems. For example, all such conventional boats must operate in sufficient depth of water to prevent the propeller from scraping bottom. However, as the propeller is rotated at greater speeds, there is a tendency to lift the bow of the boat, thereby forcing the stern deeper into the water. Therefore, in shallow water boat operators must be careful not to unduly accelerate, else the propeller will strike bottom, possibly causing severe damage. As a consequence, operations in shallow water are severely restricted and considerable skill is needed to prevent untoward accidents. 
     It has been suggested in the past to mount boat propellers at various locations other than the stern; see for example U.S. Pat. Nos. 3,636,906, 2,269,801 and 872,389, which illustrate midship mounted boat motors. 
     Catamaran-type boats have also been provided which basically include a pair of hull sections separated by an open area. These boats are generally of rather limited utility, being used primarily as pleasure craft. 
     Other prior patents depicting various types of boat constructions include U.S. Pat. Nos. 815,187, 3,548,428, 2,844,120, 3,469,549, 2,344,619 and 3,648,640. 
     Despite the multitude of prior boat constructions, however, there remains a decided need in the art for a very shallow draft, highly maneuverable boat which can be used for pleasure or commercial purposes (e.g., fishing or shrimping), while nevertheless being relatively low in cost and simple in construction. 
     SUMMARY OF THE INVENTION 
     In my present invention I employ an elongated boat hull with an amidship well. The rearward portion of the well decreases in cross-sectional area in a plane perpendicular to the longitudinal axis of the hull, creating a funnel-shaped configuration. The rearward portion of the well communicates directly with an elongated trough extending from the stern to the well. Water disturbed by the propeller in the well is channeled through the funnel-shaped portion of the well into the trough. In my preferred embodiment, the trough decreases in cross-sectional area as the stern is approached. Water forced through the trough exerts an upward force on the hull due to the decreasing cross-sectional area. 
     Accordingly, this lift on the hull provides the boat with less draft, reducing power requirements and permitting operation in shallow water. In addition, the amidship-mounted propeller provides good weight distribution during operation and permits a small turning radius. These advantages can be enjoyed by commercial as well as recreational boat operators. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a vertical sectional view of a shallow draft boat made in accordance with the present invention; 
     FIG. 2 is a bottom view thereof; 
     FIG. 3 is a front elevational view thereof; 
     FIG. 4 is a rear elevational view thereof; 
     FIG. 5 is a cross-sectional view taken along line 5--5 of FIG. 1. 
     FIG. 6 is a cross-sectional view taken along line 6--6 of FIG. 1. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     An elongated boat hull 10 has a bow 12 and a stern 14. Located between the bow 12 and the stern 14 is a funnel-shaped well 16 housing an engine 18 with a conventional thrust producing propeller 20. The well 16 is configured to channel water disturbed by the propeller 20 into an elongated trough 22. Water passing through trough 22 exits at the end of trough 22 located at the fantail or stern 14 of the boat hull 10. 
     Hull 10 includes two elongated bottom sections, 24 and 26, which are generally flat and substantially rectilinear in transverse crosssection. The sections 24, 26 are inclined upwardly from the central region of the hull toward the outside thereof in the area between a bulkhead 28 and a transom 30. The bottom sections 24 and 26 also curve gradually upwardly and inwardly forward of the transom 30 until they meet at the vertical centerline of the bow 12. The bottom sections 24 and 26 curve gradually upwards rearward of the bulkhead 28 until they meet a gunwale 32. Parallel skegs 34 and 36 are attached to the rear portion of bottom sections 24 and 26. 
     Hull 10 also includes two elongated side sections, 38 and 40, which are rectilinear in transverse cross-section and are inclined outwardly at the top thereof. The side sections 38 and 40 curve inward forwardly of the transom 30 until they meet at the vertical centerline of the bow 12. The side sections 38 and 40 curve inwardly rearwardly of the bulkhead 28 and terminate at the gunwale 32. The section 38 and the bottom 24 merge into a ridge line 42, and the section 40 and the bottom 26 merge into a ridge line 44. A top portion of the side sections 38 and 40 is removed to receive a deck 46. 
     The transom 30 is positioned transversely to hull 10 within the well 16 and inclined rearwardly at the upper edge. The transom 30 holds engine 18, shown as an outboard motor, although an inboard or an inboard/outboard engine may also be utilized. As illustrated and as is usually the case with outboard motors, the motor 18 is supported on a conventional transom-mounted bracket 41, and the generally vertical body 18a of the motor is pivotal about upright shaft 43 engaging bracket 41; moreover, the bracket allows motor pivoting about a generally horizontal axis as well to provide a trim function. At least one-half of the vertical surface area presented by the propeller 20 is disposed below the bottom sections 24 and 26. 
     The rearward portion of the well 16 includes an inclined curved piece 50, flat inclined triangular pieces 51 and 52, and flat vertical pieces 53 and 54 constructed and arranged to form a funnel 58. A stationary flat piece 55 is located across the top of the rearward portion of the well 16. The middle portion of the well 16 is provided with a movable flat top 56 mounted on a hinge 57, in order to facilitate access to the engine 18. Bottom piece 60 is forward of the well 16 and is configured to close the area bounded by the well 16 and the bottom sections 24 and 26. 
     The trough 22 rearward of the well 16 is arcuate in transverse cross-section, and is disposed along the central longitudinal axis between the bottom sections 24 and 26. As shown, the depth and width of the trough 22 decreases as the stern 14 is approached. The rearward end of the trough 22 is open where the trough 22 intersects with the stern 14. 
     In use, water disturbed by the propeller 20 is funneled through the rearward portion of the well 16 into the trough 22. As the water approaches the rearward portion of the trough 22 the reduced cross-sectional area of the trough 22 causes the water to exert an uplifting force near the stern 14. Also, during acceleration, the propeller 20 applies an upwardly force to an area near the bow 12. These two forces combine to lift the entire hull 10 while the latter remains essentially horizontal. 
     Due to upward forces, the draft of the hull 10 is considerably less than that of conventional boats. This reduced draft decreases the resistance to forward movement, which diminishes the power requirements to propeller 20. As a result, a smaller, lighter engine may be employed. Fuel consumption is also lessened, which permits smaller tanks holding less fuel. In turn, this decrease in both engine and fuel storage weight further reduces the draft of the boat. 
     My shallow draft boat may be operated in much shallower water than conventional boats. This advantage is particularly useful in the salt water bay areas, where tidal flats and sandbars are commonly encountered. Because more underwater obstacles are cleared, less accidental damage to the hull 10 and the propeller 20 will occur. The probability of higher-speed collisions with submerged objects is diminished, resulting in a much safer boat for the occupants. 
     Hull 10 also is more maneuverable than conventional boats. During turning, the walls of trough 22 present a resisting force, similar to the effect of a rudder or skeg. The bow 12 may freely move sideways because propeller 20 is disposed forward of the trough 22, while, simultaneously, the trough 22 opposes lateral movement in the rear portion of hull 10. As a result, hull 10 may be turned around in its own length at low speeds. At higher speeds, the boat will turn in a smaller radius than conventional boats without loss of steering control or propeller cavitation. 
     In addition, the hull 10 is particularly suitable for use as a fishing vessel. Since the hull 10 remains essentially horizontal while in motion, the occupants may more easily use a net or trawl. Because the engine 18 is mounted amidship, there are no entanglements with the propeller 20, allowing fish to be pulled closer to the boat. The propeller 20 may be left running as fish are pulled near the boat, as compared to conventional boats where the engine 18 must be turned off or shifted into neutral.