tugboat

Yet incredibly, sealing the ends watertight and fitting them with ballast tanks, gives enough buoyancy to tow them behind tugboats.

Three tugboats took control of the "stricken vessel" that is "unable to manoeuvre".

Clyde tugboats fired water cannons to send off the submarine and its 110-strong crew on Tuesday, before being welcomed by waving well-wishers as it sailed into Plymouth Sound.

The deaths of two men when a tugboat capsized on the Clyde near Greenock was caused by a "breakdown" in safety procedures, an accident report has found.

Controllers will allow the orbit of the ISS to naturally decay over a period of time, and after removing the last crew will command the tugboat to execute the final de-orbit manoeuvre.