Abstract: A vessel assembly and related assembly method that includes a flexible J-tube assembly that bends in compliance during assembly to a vessel to ensure locating of a filter unit against an inside bottom surface of the vessel while accommodating longitudinal part tolerances greater than that of the prior art. The flexible J-tube assembly is disposed within the interior of the vessel such that an upper end of the flexible J-tube assembly is connected to an inside top portion of the vessel, and a distal end of the flexible J-tube assembly is located against the inside bottom surface of the vessel. The resiliency of the flexible J-tube assembly permits the distal portion of the flexible J-tube assembly to stay located against the inside bottom portion of the vessel regardless of longitudinal dimensional variations of the flexible J-tube assembly and the vessel.