Embodiments include a retrofit pontoon system including a pontoon, the pontoon having a pontoon body defining a first cavity, a retrofit assembly, the retrofit assembly including a first lateral tube, wherein the first lateral tube is sized to pass through a first aperture formed in the pontoon body and a selectively fillable container, where the first lateral tube is operably coupled with the selectively fillable container, a main tube, where the main tube is fluidly coupled with the first lateral tube, and a pump, the pump being coupled with the main tube such that operation of the pump selectively fills and drains water from the selectively fillable container, where filling the selectively fillable container lowers the profile of the pontoon in the water and emptying the selectively fillable container raises the profile of the pontoon in the water.

A method of operating a boat to produce a surf wake includes partially filling a transverse ballast tank, moving the boat through a body of water, rolling the boat toward either its port or starboard side to shift the water in the transverse ballast tank such that at least some of the water in the transverse ballast tank moves from one side of a longitudinal centerline of the boat to the other side of the centerline, and creating a surf wake on the side toward which the boat is rolled.

A method of operating a boat to produce a surf wake includes partially filling a transverse ballast tank, moving the boat through a body of water, rolling the boat toward either its port or starboard side to shift the water in the transverse ballast tank such that at least some of the water in the transverse ballast tank moves from one side of a longitudinal centerline of the boat to the other side of the centerline, and creating a surf wake on the side toward which the boat is rolled.

Wakeboats that include an aquatic invasive species control apparatus are provided. These wakeboats can include: a wakeboat with a hull; at least one throughhull fitting in the hull of the wakeboat; an irradiation chamber in fluid communication with the at least one throughhull fitting, the irradiation chamber having a radiation source; and at least one water destination aboard the wakeboat. Methods for irradiating invasive aquatic species aboard a wakeboat are also provided. The methods can include: receiving water from outside the wakeboat hull; and irradiating water aboard the wakeboat prior to discharging the water.

A pumping system featuring a pump chamber configured with a central portion having a tangential outlet, and configured with a tubular coupling end portion having inwardly flexible rim portions on one side; and a mounting base, having a circular portion with an inner circumferential rim configured to receive and engage the inwardly flexible rim portions of the tubular coupling portion of the pump chamber so as to be rotationally coupled to the pumping chamber so that the pumping chamber may be rotated 360° in relation to the mounting base.

A pumping system featuring a pump chamber configured with a central portion having a tangential outlet, and configured with a tubular coupling end portion having inwardly flexible rim portions on one side; and a mounting base, having a circular portion with an inner circumferential rim configured to receive and engage the inwardly flexible rim portions of the tubular coupling portion of the pump chamber so as to be rotationally coupled to the pumping chamber so that the pumping chamber may be rotated 360° in relation to the mounting base.

A pneumatically controlled shellfish aquaculture apparatus is provided. A frame has containers for holding shellfish secured to the top side of the frame and tanks secured to the bottom side of the frame. Each tank has an air supply line connected to the tank and an opening on the bottom side of the tank. Each air supply line is connected to a manifold for controlling airflow to the tanks. Air is used to displace water in the tanks by pushing the water out of the openings in the bottom of the tanks in order to float the frame. To submerge the frame, the tanks are depressurized to allow water to displace the air in the tanks. When floating, the tanks lift the frame and the containers out of the water to allow air desiccation in order to prevent bio-fouling of the equipment and shellfish.

A ballast water treatment device includes a filtration device and an irradiation device that irradiates, with ultraviolet rays, filtered water that has been filtered. The filtration device is a device that removes 99.999% or more of L-size organisms having a minimum part size of 50 μm or more, and 90% or more of S-size organisms having a minimum part size of 10 μm or more and less than 50 μm. The irradiation device is capable of sterilizing the filtered water at a flow rate of 250 m.sup.3/h and a power consumption of 13 kW to eliminate 90% of S-size organisms immediately after a sterilization treatment.

A ballast water treatment device includes a filtration device and an irradiation device that irradiates, with ultraviolet rays, filtered water that has been filtered. The filtration device is a device that removes 99.999% or more of L-size organisms having a minimum part size of 50 μm or more, and 90% or more of S-size organisms having a minimum part size of 10 μm or more and less than 50 μm. The irradiation device is capable of sterilizing the filtered water at a flow rate of 250 m.sup.3/h and a power consumption of 13 kW to eliminate 90% of S-size organisms immediately after a sterilization treatment.

A ballast water treatment system includes an ultraviolet irradiation device which irradiates ballast water flowing through a treatment line (a pipe) with ultraviolet rays, and a control unit. The ultraviolet irradiation device includes a light source which emits ultraviolet rays, and an illuminance sensor sensing an illuminance of ultraviolet rays received by the ballast water. The control unit controls the ultraviolet irradiation device to maintain at a prescribed dose a dose calculated using an illuminance sensed by the illuminance sensor and a flow rate of ballast water which flows through the ultraviolet irradiation device. When the sensed dose cannot be maintained at the prescribed dose by controlling the ultraviolet irradiation device, the control unit reduces a treatment flow rate of the ballast water which flows through the treatment line.