ridgerope

from The Century Dictionary.

• noun Nautical: The central rope of an awning, usually called the backbone.
• noun The rope along the side of a ship to which an awning is stretched
• noun One of two ropes running out on each side of the bowsprit for the men to hold on by.
• noun A ridge-band.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Naut.) See Life line (a), under Life.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun nautical A lifeline.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun either of a pair of lifelines running alongside the bowsprit of a ship