High maneuverability towcraft

Abstract

An open-backed towable watercraft (towcraft) which is maneuverable from side-to-side by the intuitive leaning action of one or more riders thereon. The towcraft consists of a partial hull structure, upwardly curved at the bow end with a predominantly flat bottom and stern; and, an inflated, or other cushioned, upper portion which is fitted with handles for the riders to securely grasp. At least three downward-projecting fins are removably attached to the partial hull structure. A first fin of sufficient size and draft is ventrally located along the craft's centerline, at its front. A second and third fin, smaller in size and draft to the ventral fin, are laterally spaced-apart, preferably, at a station aft of the craft's center of gravity. The towline attachment to the front of the towcraft is at a point above the craft's operative waterline and situated such that the towline line-of-force intersects, or very nearly intersects, the ventral fin's effective zero-moment vertical center line for all normal towline attitudes.

Description

BACKGROUND OF THE INVENTION

A primary object of the present invention is to devise the most basic highly maneuverable towcraft that one rider, or multiple riders can operate, not only from the standpoint of construction and cost, but also in its operation.

SUMMARY OF THE INVENTION

This invention consists of a thin, lightweight, structural lower hull comprising the lower-most part of the towcraft, and a cushioned upper part. The cushioned upper, consisting of either foam and one or more inflation chambers, or a combination of both, presents a resilient surface to the rider and also functions as a flotation means.

The general shape of the towcraft resembles that of an elongated horseshoe. In one embodiment, the side and front portion above the hull consists of one or more fabric-covered inflation chambers, while the upper surface of the flat floor is foam covered, or, more preferably, has an inflated half-tube on which a kneeling person may straddle. Handles are provided in the cover as a simple means whereby one rider, or multiple riders, may shift their weight from side-to-side without changing their grip. The stern end of the towcraft is left open thereby making it easy for riders to climb aboard. Also, the flat exposed floor at the stern end allows any collected water to drain away. Further, the flat termination of the floor at the stern end counters any Coanda Effect.

The bow end of the hull is made to sweep upwards and back a short distance above the craft's waterline. Near its upper extent, lying along the centerline of the towcraft, a D-ring, strap, or other robust towline attachment means is provided. Immediately below the simple, fixed, towline attachment point is the areal moment center of a fixed primary water-engaging device consisting of a ventral fin. The ventral fin is removably attached to the bow-end of the hull by its neck portion. As a result of the ventral fin's forward mounting, and its characteristic balanced, or nearly balanced (front/rear area) design, the forward-most end of the ventral fin can extend beyond the front of the towcraft's hull. Therefore, it is preferable that the leading edge of the ventral fin is itself cushioned with a layer of rubber or other elastomeric material.

A short distance astern of the ventral fin, two spaced-apart, slightly toed-out, trailing fins are provided. When a leaning action by the rider(s) ensues, the drag differential between its left and right side causes the towcraft to rotate in the direction of the lean, thereby causing the it to proceed in that direction.

It should be noted that the substitution or addition of flexible trailing fins, or pivotable trailing fins, or curved trailing fins, an extra set of spaced-apart trailing fins positioned aft of the first set, an operable pivoting handlebar, or a stationary one with twist grips which manipulate alternate pivoting fins sequentially, or other contemplated embodiments do not depart from the scope of the invention.

DESCRIPTION OF THE DRAWINGS

With reference to FIG. 1, the present invention consists of a hull 1, a bow-end 1A, a stern-end 1B, inflated upper 2 (shown covered), ventral fin 3, ventral fin areal moment center 3A, spaced-apart trailing fins 4A and 4B, towline 5, towline attachment point 6, and inflated half-tube 7.

Claims

I. A high maneuverability towcraft comprising: a means for ensuring that the towline line-of-force (always) intersects, or nearly intersects, the primary water-engaging device's areal moment's vertical centerline during all normal on-the-water operations; an above-the-waterline towline attachment means; a means whereby more than one rider may cooperatively participate in maneuvering the towcraft; a means for easy ingress onto the towcraft from the rear of the towcraft; a means whereby the rider(s) may secure a sure grip on the towcraft while at the same time allow for aggressive weight-shifting.

II. The high maneuverability towcraft of claim 1, wherein the towline is simply attached to a point directly above the forward-mounted ventral fin's (areal) effective zero-moment('s) vertical center line, and two parallel-aligned, or slightly toed-out, spaced-apart trailing fins (slightly toed-out) such that hull rotation is induced upon a rider(s) leaning or weight-shifting action, and an elastomer-covered, flat, rigid, floor termination at the extreme stern-end of the towcraft whereby collected water is automatically drained away, and a centered, longitudinal, inflated half-tube whereby (the) kneeling rider(s) are further supported both laterally and vertically.