Patent Application
20190016430
Not Applicable
Not Applicable
The present application is directed to marine vessel configurations. More specifically, it is directed towards a boat configuration, specifically a runabout with a single level passenger cabin that involves placement of the engine forward of the longitudinal centerline of the boat and at a level in the boat that is at least below the cabin seat level.
Modern runabout recreational boats ranging in size from 16 to 35 feet in length are designed for a variety of applications. Sport fishing, skiing (direct drive), wakeboarding, surfing, and runabouts all share the same basic configuration and layout consisting of a single level passenger cabin, a forward driver's cockpit and passenger cockpit with an engine located within the hull. The general types of runabout recreational boat drives include inboard outboard (I/O) drives (or stern drives), inboard drives (including V drives), pod drives, and outboards.
All of these configurations, regardless of hull or passenger cockpit design, suffer from various issues related to engine placement and weight distribution.
An I/O drive is a form of marine propulsion which combines inboard engine power with outboard drive. The engine typically sits just forward of the boat's transom while the drive unit (outdrive) lies outside the boat hull. I/O drives are mounted on the rear most, vertical transom of the boat and offer advantages in the ability to trim, positively and negatively from neutral (water level), to adjust the running attitude of the boat. An I/O may include dual counter rotating propellers that are power efficient and deliver greater acceleration. However, the rear mounting position of the engine results in certain disadvantages, particularly concerning trimming leverage. This can result in excessive bow rise under acceleration and excessive roll when steering on plane.
Bow rise is the tendency for the front of the boat to rise and the rear of the boat to tuck during the acceleration to plane phase. All modern runabouts suffer in varying degrees from excessive bow rise under acceleration to plane. This is most evident in outboards as the drive thrust and weight biases are generally further back. To a lesser extent I/O's suffer from excessive bow rise, as the drive thrust is still applied rear of the transom and despite having an engine inboard of the transom. Inboards (or V-drives) are an improvement over the I/O, with drive thrust applied under the boat and forward of the transom, but with the engine substantially in the same position as the I/O. Ski boats (direct drives) offer the least bow rise with thrust applied similar to the V-drive (under the boat); however, while the engine placement is forward of the transom, the engine is still behind the longitudinal center line, and substantially above the floorboard in the aft passenger compartment of the vessel. Bow rise contributes to reduced forward visibility when accelerating to plane. Once on plane, bow rise can continue to greatly affect visibility and therefore safety. Further, bow rise while on plane contributes to a certain degree of discomfort when crossing waves or in choppy conditions as the bow is pushed, or buoyed, upward by the waves and/or chop.
In each of the foregoing configurations, the engine placement also plays a key role in cockpit layout and in determining the available space for passengers and cargo. With the exception of the direct drive, all of these configurations greatly limit the access to the transom area, including the swim platform. For PO's and V-drives the engine placement at the rear of the boat, and substantially above the floorboard height, reduces available space for seating and cargo. In the case of a direct drive, the engine is located toward the center of the boat and above the floorboard, greatly reducing available passenger seating and storage space.
Historically, the engine of recreational boats migrated to the transom of the boat to remove weight from the bow and allow the bow to rise under acceleration and promote planing and hydrodynamic lift at the rear of the boat. This was necessary because it placed less stress on the engine to lift the bow out of the water as the boat accelerated to plane. The boat would then plane predominantly on the rear half of the hull's surface where the engine weight is carried. The bow then would run largely out of the water at an exaggerated positive (bow up) running angle. The hull's design evolved accordingly such that the center of hydrodynamic lift (CHL) was moved aft to carry the weight of the engine. By lifting the bow out of the water on plane rear engine boats have enjoyed improved speeds and efficiency from the reduction of hydrodynamic drag on the hull.
The forward engine design of the present invention proposes to counter the current thinking of rear engine rear biased CHL boats to create a new generation of forward engine planning boats with a V-hull to accommodate the engine forward and below deck. However, the engine forward concept is counterintuitive to all state-of-the-art rear engine runabout boat designs where lifting the bow is initiated in order to facilitate acceleration to planning speeds and promote greater speeds and efficiency once on plane. Accordingly, it is an object of the present invention to supply a boat configuration that provides improved acceleration to plane performance, less bow rise during acceleration to plane and while on plane, improved ride comfort, improved handling, and increased interior passenger room, along with better wake performance. A forward engine runabout boat will draft deeper in the water and with greater hydrodynamic drag than its rear engine counterpart, and at planing speeds this disadvantage becomes even greater. However, it is believed that the opportunity to improve towing performance, ride comfort, wake performance, interior space, and a reduction in bow rise will outweigh the lack of speed for recreational boaters interested in wake boarding, skiing, and surfing or who value a more comfortable ride and the safety of a lower bow rise over top speed
These and other objects and advantages over the prior art will become apparent to those skilled in the art upon reading the detailed description together with the drawings.
A forward engine configuration according to one example embodiment of the present general inventive concept involves moving the engine of the marine drive system forward of the longitudinal center line of a V-hull boat, under the walking deck or the floorboard of the passenger cabin, and at or near the lowest point in a V-hull, close to the keel. Doing so adjusts the weight bias of the boat substantially forward and deeper in the hull than is possible for other configurations. Drive thrust is provided by coupling the engine directly to a pod drive, or using a shaft to transfer drive power directly to a strut and propeller (as in a direct drive), or through the shaft to a pod or traditional transom mounted I/O. It is also envisioned that a pod drive could be mounted directly to the engine and located forward of the longitudinal center of gravity of the boat or centerline of the boat. In such an embodiment, a rudder, or a multitude of rudders, could be used in conjunction with a non-steering pod. In various exemplary embodiments, the engine is coupled to a pod, stern drive, or direct drive through a shaft. The effect of moving the engine forward of the longitudinal centerline and at least below seat height results in moving the center of gravity forward and lowering it within the hull. This also results in improved acceleration to plane performance, less bow rise, improved ride comfort, improved handling, increased interior passenger room, and better wake performance.
The following example embodiments are representative of example techniques and structures designed to carry out the objects of the present general inventive concept, but the present general inventive concept is not limited to these exemplary embodiments. In the accompanying drawings and illustrations, the sizes and relative sizes, shapes, and qualities of lines, entities, and regions may be exaggerated for clarity. A wide variety of additional embodiments will be more readily understood and appreciated through the following detailed description of the example embodiments, with reference to the accompanying drawings in which:
As illustrated in
Traditional state-of-the-art boat designs utilize this rear engine boat placement; and the engine can be coupled to a number of conventional PTOs and means of propulsion. For instance, as illustrated in
Referring to
As discussed above, a marine drive system includes the engine 105, the PTO, and a means of propulsion. The present invention involves placing the engine 105 forward of the longitudinal centerline 115 and, depending upon the exemplary embodiment, either below the level of the deck 140 or below the level of seat height 150. Doing so allows adjustment of the weight bias of the boat substantially forward and deeper in the hull than is possible for state-of-the-art boat configurations, such as are illustrated in
This still allows variations on the type of drive system for V-hull boat 110. In this regard, as shown in
In another exemplary embodiment, illustrated in
The effects of this general design, which changes the weight distribution by moving the center of gravity of the boat forward and lower, include improved ride comfort, less bow rise during the acceleration to plane phase and while on plane, improved handling, and increased interior passenger room, potentially quicker acceleration to plane, along with improved wake performance. Less bow rise means quicker time to plane and better forward visibility during acceleration to plane and while on plane. Once on plane, the forward biased center of gravity will allow the rear of the boat to ride higher in the water giving the boat a more neutral running angle at all speeds. Trimming via a POD, I/O, or jet drive at or near the transom will be more effective as the engine weight is moved forward.
A forward engine design places the mass of the engine at or near the keel, at the deepest part of the hull, thus helping the keel to cut through a wave rather than being pushed or buoyed up by the wave. The result is a more stable ride with less passenger jostling in choppy or wavy conditions. The hull is also less prone to slap the waves thus reducing the safety issues related to vessel porpoising.
A forward engine deep V boat design locates the engine in an area of the boat that is generally unused. It moves the engine from an area near the transom, as with prior art boats, and places the engine under the floorboard in an area commonly used as passenger walkway to the bow of the boat. In some cases, as in a ski boat or a small runabout, it may be necessary to raise the floorboard height to create a step feature or a bench seat in order to easily clear the top of the engine, but in no case is it necessary to raise the deck any higher.
Wake performance behind the boat is largely dictated by the shape of a triangular area of the hull at the rear of the boat, and how much water that area of the hull displaces. In applications where wake performance behind the boat is important, the forward engine design removes weight from the back of the boat and allows the rear of the boat to ride higher in the water and produce a smaller wake more conducive to skiing. By adding ballast to the boat, one can displace more water and create larger wakes for surfing and wakeboarding. In this way, a boat using a forward engine placement satisfies both requirements in a single boat design.
While embodiments are described herein, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicant's general inventive concept.
