What is another word for "bilge"?

Roget's Thesaurus (1911) lists these synonyms for "bilge": adown, base, baseboard, based, basement, basis, below, beneath, bottom, built, cellar, centerboard, concave, crouch, crouched, dado, debased, debasement, deck, depress, depression, down, downwards, earth, ebb, feet, flag, flat, floor, foot, footing, foundation, fundamental, ground, grovel, hardpan, hold, hoof, horizontal, keel.