Various examples of transferring a watercraft between land and water are disclosed. When a vehicle receives a transfer signal, the vehicle locates a launch ramp, and the vehicle moves to the launch ramp. A trailer attached to the vehicle moved into the water using the launch ramp, such that a watercraft can be transferred between land and water via the trailer.

A reversible spindle embodiment for a small sailboat dolly axle includes 2 spindle elements, one on each end of the same reversible spindle embodiment connected by a central interconnecting mounting element. Each spindle element is designed to mate with a wheel hub having a different size diameter and/or width. The unused spindle element and the central interconnecting mounting element are inserted into the hollow end of the dolly axle and secured with fasteners through the walls of the axle and mounting element. The desired spindle element is inserted through the wheel hub and secured. To mount a wheel having a different hub size matching the unused spindle element, the fasteners are removed, the reversible spindle is rotated 180 degrees and the fasteners reinstalled.

A trailer comprising a frame, wheels rotatably attached to the frame, opposing side panels having a lower edge, opposing first and second vertical edges and a top edge. The trailer includes a front panel having a front panel upper edge, the front panel attached at opposite front panel vertical edges to the first edge of the side panels. The trailer includes a floor disposed on top of the trailer frame and a boat removably attached to the top edge of the opposing side panels. The trailer may include bunkers extending along the trailer length, the bunkers retractable from a position above the trailer floor to a position wherein the bunkers are disposed in or below the trailer floor. The trailer may include an upper frame pivotally attached to the front panel upper edge wherein the boat is removably attached to the upper frame.

Methods and systems for monitoring a load in a trailer coupled to a vehicle. One method includes determining, with an electronic processor, an initial weight on a rear axle of the vehicle when the load is engaged with the trailer coupled to the vehicle. The method also includes monitoring, with the electronic processor, a current weight on the rear axle of the vehicle based on data collected by a sensor. The method also includes comparing, with the electronic processor, the initial weight and the current weight. The method also includes automatically generating, with the electronic processor, a notification when the current weight is different than the initial weight by a predetermined threshold.

An expandable and contractible boat comprises a first outer hull and a second outer hull symmetrically shaped and arranged with respect to one another. The first and second outer hulls are movable relative to one another, and each of the first and second outer hulls includes an outboard side portion, an inboard side portion, a bottom portion between the outboard side portion and the inboard side portion, and a concave chine portion connecting the outboard side portion and the bottom portion. A cross-section of each of the first and second outer hulls is recessed at the concave chine portion.

The invention relates to a craft in the form of a body to be sat or laid upon by a user and provided with power for use in a body of water. There is also provided a method for the use of the craft in game play and the use of the same in a manner which allows the power source for the drive to be managed. A system for transport, charging and/or communication with the craft from onshore is also provided, along with a system to allow the use of the craft within a specified area on the body of water to be maintained and controlled.

A device for finding the center of mass for a marine or similar vessel that includes a cradle seated on a fulcrum that can hold the vessel. The frame upon which the cradle is positioned is shaped to allow the front and back of the cradle to tip upwards and downwards much like a seesaw depending on how the vessel is balanced in the cradle. The device can be used to locate the center of mass or gravity of a vessel or to determine the position of a vessel such that it applies a predetermined amount of weight to the front or back end of a trailer or other supporting device. Scales can be located at either end of the device to calculate the amount of weight exerted by the vessel at either end of the cradle.

An amphibious transport apparatus includes forward and aft ends, a pair of spaced apart pontoons including tracks, and a transversely extending structure, which can include a platform, that spans between the pontoons and connects the pontoons together. The amphibious transport apparatus further includes a sled vessel that can be used to transport materials or personnel. The sled can be releasably attached to the amphibious transport apparatus with tow bar and a pivotal connection. Said tow bar can be rotatable between an upper storage position wherein the tow bar engages the vessel away from said pivotal connection and above a terrain surface, and a lower towing position. A towing position of said amphibious craft and sled can be defined by the sled connected to the amphibious craft at the releasable pivotal connection, with the amphibious craft being self propelled with said tracks for engaging the underlying terrain and with the sled in the lower towing position so that the sled bottom drags along on the underlying terrain during movement of the amphibious transport apparatus and sled. A trailer for loading and unloading the sled can also be provided. The amphibious craft can push the sled onto the trailer during loading.

A structural cross frame connector is described having a multipurpose system of attachment. The device has two main forms one with a vertical offset and one without this vertical offset. The central portion has an arch by which weight is distributed accordingly. The connectors have a a group of pass through holes whereby a pass through rod is attached thereto using fasteners. Various structural members can be attached to the pass through rod using pass right and left pass through cavities typically used as structural support members and a central pass through cavity typically used as a hitching station. Leaf springs are also mountable on pass through rods and freely operate on another connector right and left pass through cavity for use as a suspension system.

The boat trailer having an inflatable bladder is a boat trailer with an inflatable bladder located under the rear end of the trailer. The bladder is coupled to an air hose that runs to a hose connecter at the front of the trailer. The bladder is retained in place by a combination of longitudinal and lateral support rails, which are part of the trailer frame and by a bladder barrier that covers the bladder and prevents it from rising above the top of the trailer. If the trailer is backed down the boat ramp and the wheels leave the boat ramp at an end-of-ramp drop-off, a source of compressed air may be used to inflate the bladder. This provides buoyancy to elevate the trailer wheels so that the tow vehicle may pull the trailer up the boat ramp.