Smith's Bible Dictionary (1863)
(Acts 27:17) [Ship]
Hastings' Dictionary of the Bible (1898)
UNDERGIRD'ING a vessel means to pass a strong cable around the hull to prevent it from opening. The ship which carried St. Paul to Italy was undergirded. Acts 27:17. Lord Anson mentions a Spanish man-of-war that was saved by throwing overboard one tier of guns and taking six turns of a cable around the ship.