In a front mounted lift for watercraft, the torque exerted by the lift on the dock is limited by a combination of a first buoyant force, being air trapped within the lift tanks, and a second buoyant force, being flotation devices connected to the rear of the lift. In a preferred embodiment, the primary buoyant force is achieved by the extension of an air supply and exhaust hose into each tank compartment to a level below the uppermost level of the tank chamber. When the water level in each tank compartment covers the hose opening, the air trapped in the tank provides a buoyant force to counter most of the submerged lift weight. The depth of the hose is selected so that the weight of the lift slightly exceeds the primary/buoyant force. This permits the lift to sink but significantly minimizes the torque exerted on the connection of the lift to the dock. The secondary buoyant force preferably consists of a pair of buoyant guides which prevent the rear of the lift from sinking to an undesirable depth. This secondary force further reduces the torque on the dock. These buoyant guides also serve to direct the watercraft into its proper position on the lift during the landing process and to support the watercraft in its operational attitude on the lift when the watercraft is raised out of the water.
In a lift for mooring a boat stern-on, a pair of horizontally spaced guide members is fixed to the sea wall. A frame is fixed to a pair of substantially parallel hydro-pneumatic buoyancy tanks to provide a flotation platform for supporting the hull of the boat. The stern end of each of the tanks is connected to the guide members. The guide members limit movement of the platform away from the sea wall and along the sea wall but permit vertical reciprocation of the stern ends of the lift tanks in unison and restrict the lift from listing during operation.
Apparatus for raising and lowering boats in water. The apparatus consists essentially of at least one float that is attached to the hull of the boat and is guided along the surface of the hull of the boat at least partially below water level when a force is applied to it. Preferably at least two floats that are permanently or displaceably attached to the apparatus support in the longitudinal direction and are provided on the side of the support which is intended to accommodate the hull of a boat. The entire device is designed so it is adjustable in height and is connected to a stationary land-based mooring point with an articulated joint. This device is especially reliable for raising a boat out of the water and docking the boat above the water line without risking canting. This result is possible in an inexpensive and very simple manner with the invention. The usable width of the entire device is greatly reduced from previously known such devices.
Apparatus for raising and lowering boats in water. The apparatus consists essentially of at least one float that is attached to the hull of the boat and is guided along the surface of the hull of the boat at least partially below water level when a force is applied to it. Preferably at least two floats that are permanently or displaceably attached to the apparatus support in the longitudinal direction and are provided on the side of the support which is intended to accommodate the hull of a boat. The entire device is designed so it is adjustable in height and is connected to a stationary land-based mooring point with an articulated joint. This device is especially reliable for raising a boat out of the water and docking the boat above the water line without risking canting. This result is possible in an inexpensive and very simple manner with the invention. The usable width of the entire device is greatly reduced from previously known such devices.
A lift for a watercraft has plastic reinforcing brackets which engage in pockets in the thin-walled plastic floatation tanks of the lift and which provide mounting flanges at the top surfaces of the floatation tanks for abutment with mounting pads which connect to the watercraft support frame. The brackets are engaged on the floatation tanks and the pads overlap and are bolted to the plastic brackets, so that the pads are locked against but not bolted to the floatation tanks. Thus, the integrity of the tanks is not compromised by assembly-associated openings through the tank walls. Furthermore, the bolts are above the tank waterlines so that no corrosive material is disposed below the waterlines.
The carrier includes a cradle having an elongated spine and a number of ribs which are spaced along the length of the spine. The spine is pivotally attached to a larger boat such that an end of the spine may be raised or lowered. When the end of the spine has reached its lowermost extent, it is immersed in water and allows a smaller boat to be floated into the cradle. When the end of the spine is raised to its uppermost extent, the smaller boat is lifted entirely out of water. A hoist or actuator serves to raise and lower the end.
