What does Capstan, steam mean?
Meaning of "Capstan, steam"
A vertical drum or barrel operated by a steam engine and used for handing heavy anchor chains, heavy hawsers, etc. The engine is usually non-reversing and transmites its power to the capstan shaft through a worm and worm sheel. The drum is fitted with pawls to prevent overhauling under the strain of the hawser or chain when the power is shut off. The engine may be disconnected and the capstan operated by hand through the medium of capstan bars.