The Collaborative International Dictionary of English v.0.48:
Relieving \Re*liev"ing\, a.
Serving or tending to relieve.
Relieving arch (Arch.), a discharging arch. See under
Discharge, v. t.
Relieving tackle. (Naut.)
(a) A temporary tackle attached to the tiller of a vessel
during gales or an action, in case of accident to the
(b) A strong tackle from a wharf to a careened vessel, to
prevent her from going over entirely, and to assist in
righting her. --Totten. --Craig.