Tether for an inspection vehicle

A method for inspecting components within a housing at least partially filled with a liquid medium, the method comprising:

• connecting a tether to an submersible inspection vehicle;
• deploying the submersible inspection vehicle into the housing;
• moving the submersible inspection vehicle within the housing with a liquid drive propulsion device;
• sensing a portion of the components with a sensor operably coupled to the submersible inspection vehicle;
• and
• controlling movement of the tether with a controllable buoyancy system, the controllable buoyancy system comprising one or more floating bodies and one or more buoyant elements connected to the tether;
• and
• adjusting a volume of gas and a volume of liquid within the one or more floating bodies and the one or more buoyant elements by the one or more floating bodies and the one or more buoyant elements, thereby controlling a buoyancy level and a floating height of the one or more floating bodies and the one or more buoyant elements.

A tether system for a liquid propelled submersible inspection vehicle comprising:

• a tether configured to connect a control system to the submersible inspection vehicle;
• a controllable buoyancy system operably coupled to the tether;
• the controllable buoyancy system comprising one or more floating bodies and one or more buoyant elements connected to the tether;
• and
• the one or more floating bodies and the one or more buoyant elements being configured to adjust a volume of gas and a volume of liquid within the one or more floating bodies and the one or more buoyant elements, thereby controlling a buoyancy level and a floating height of the one or more floating bodies and the one or more buoyant elements.