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 watercraft having a body with an opening for a user, a seat, at least one drive mechanism placed at least partially within the opening; an intake configured to allow a flow of water from a body of water surrounding the watercraft; a pump configured receive the flow of water and accelerate the flow of water, and a user controlled discharge configured to receive the flow of accelerated water from the pump and discharge the accelerated water to the water surrounding the watercraft such that the watercraft moves in a direction chosen by the user.

The present disclosure provides power source assemblies aboard a watercraft. The power source assemblies can include: an engine having a crankshaft; a variable ratio drive assembly operably engaged with the crankshaft; and an engine powered accessory operably engaged with the variable ratio drive assembly. The present disclosure also provides methods for distributing power aboard a watercraft from a crankshaft of an engine. The methods can include: using a crankshaft of an engine to drive a variable ratio drive assembly; and using the variable ratio drive assembly to drive an engine accessory over a narrower RPM range while operating the crankshaft over a wider RPM range.

The present disclosure provides power source assemblies aboard a watercraft. The power source assemblies can include: an engine having a crankshaft; a variable ratio drive assembly operably engaged with the crankshaft; and an engine powered accessory operably engaged with the variable ratio drive assembly. The present disclosure also provides methods for distributing power aboard a watercraft from a crankshaft of an engine. The methods can include: using a crankshaft of an engine to drive a variable ratio drive assembly; and using the variable ratio drive assembly to drive an engine accessory over a narrower RPM range while operating the crankshaft over a wider RPM range.

An actuator comprises a housing and a drive tube assembly disposed within the housing. The drive tube assembly includes a drive tube provided with internal threads, a piston nut provided with external threads which threadedly engage the inner threads of the drive tube, and an output shaft connected to the piston nut. A motor rotates the drive tube to cause the piston nut to reciprocate along a length of the drive tube and the output shaft to reciprocate relative to the housing. There are bearings which transmit axial loads from the drive tube to the housing and transmit radial loads from the drive tube to the housing.

A vessel including a hull, an upper deck, an accommodation structure extending above the upper deck, a propulsion system powered by ammonia as a fuel, and a tank for storing ammonia for supplying the propulsion system, wherein the tank is located aft of the accommodation structure.