pus , ▁where ▁it ▁seems ▁most ▁frequently ▁to ▁describe ▁the ▁N ile ▁b arg es ▁of ▁the ▁P to le ma ic ▁ph ara oh s . ▁ ▁Both ▁of ▁these ▁us ages ▁may ▁lead ▁back ▁through ▁the ▁Pho en ician ▁to ▁the ▁A kk ad ian ▁kal ak ku , ▁which ▁denotes ▁a ▁type ▁of ▁river ▁bar ge . ▁The ▁A kk ad ian ▁term ▁is ▁assumed ▁to ▁be ▁derived ▁from ▁a ▁S umer ian ▁ante ced ent . ▁A ▁modern ▁ref lex ▁of ▁the ▁word ▁is ▁found ▁in ▁Arab ic ▁and ▁Turkish ▁ke lek ▁" raft ; ▁river bo at ". ▁ ▁Orig ins ▁▁ ▁By ▁the ▁Late ▁Middle ▁A ges ▁the ▁c og , ▁and ▁c og - like ▁square - rig ged ▁vessels ▁equ ipped ▁with ▁a ▁rud der ▁at ▁the ▁stern , ▁were ▁widely ▁used ▁along ▁the ▁coast s ▁of ▁Europe , ▁from ▁the ▁Mediter rane an , ▁to ▁the ▁Balt ic . ▁Given ▁the ▁conditions ▁of ▁the ▁Mediter rane an , ▁gal ley ▁type ▁vessels ▁were ▁extens ively ▁used ▁there , ▁as ▁were ▁various ▁two ▁m asted ▁vessels , ▁including ▁the ▁car av els ▁with ▁their ▁late en ▁s ails . ▁These ▁and ▁similar ▁ship ▁types ▁were ▁familiar ▁to ▁Portuguese ▁navig ators ▁and ▁ship w right s . ▁As ▁the ▁Portuguese ▁gradually ▁extended ▁their ▁trade ▁ever ▁further ▁south ▁along ▁Africa ' s ▁Atlantic ▁coast ▁during ▁the ▁ 1 5 th ▁century , ▁they ▁needed ▁larger , ▁more ▁dur able ▁and ▁more ▁advanced ▁sail ing ▁ships ▁for ▁their