Unitary plastic boat lift buoyancy tank

A buoyancy tank for a boat lift comprising an elongated plastic shell having a transverse bulkhead therein formed by molding said tank with said bulkhead secured therein at a process temperature, said tank being molded from plastic having a melting temperature lower than said process temperature and said bulkhead being formed from plastic having a melting temperature slightly higher than said process temperature whereby said tank and said bulkhead are fused together along a perimeter of said bulkhead.

A grip for connecting framing for a boat lift to a buoyancy tank comprising a resiliently compressible member having a rigid plate along a back wall thereof and an inwardly narrowingly tapered recess in a front wall thereof, a rigid member tapered for insertion into said recess and means for pulling said rigid member into said compressible member to spread said recess.

An assembly for attaching boat lift components to a buoyancy tank having a pair of opposed lengthwise grooves in upper portions of sidewalls thereof comprising an elongated spacer, first and second brackets extending downwardly, one from each end of said spacer, first and second grips, one fixed to a lower end of said first and second brackets, respectively, each said grip being a resiliently compressible member having a rigid plate along a back wall thereof and an inwardly narrowingly tapered recess in a front wall thereof, first and second rigid members tapered for insertion into said recesses of said first and second grips, respectively, and first and second means for pulling said first and second rigid members, respectively, into said first and second grips to spread said recesses and compress said grips in said grooves.

A method of making a buoyancy tank for a boat lift comprising the steps of securing a bulkhead formed from plastic having a melting temperature in a tank mold, filling said tank mold with plastic powder having a melting temperature lower than the bulkhead plastic melting temperature, molding the tank at a process temperature slightly lower than the melting temperature of the bulkhead plastic and greater than the melting temperature of the powder to fuse the tank and the bulkhead together along a perimeter of the bulkhead.