A whaleboat is a type of open boat that is relatively narrow and pointed at both ends, enabling it to move either forwards or backwards equally well. It was originally developed for whaling, and later became popular for work along beaches, since it does not need to be turned around for beaching or refloating.
Whaleboats are traditionally oar-powered, although in whaling use often had a dismountable mast and sails, too. After 1850 most were fitted with a centerboard for sailing. When sailing, steering was with a rudder; when rowing, steering was done with an oar held over the stern. Whaleboats used in whaling had a stout post mounted on the aft deck, around which the steersman would cinch the rope once the whale had been harpooned, and by which the whale would drag the boat until it was killed.
The term "whaleboat" may be used informally of larger whalers, or of a boat used for whale watching. On modern warships, a relatively light and seaworthy boat for transport of ship's crew may be referred to as a whaleboat or whaler. It may also refer to a type of vessel designed as a lifeboat or "monomoy" used for recreational and competitive rowing in the San Francisco Bay Area and coastal Massachusetts.