The whaleback was a unique design of a cargo ship with a hull that continuously curved above the waterline from the vertical to horizontal leaving, when fully loaded, only the curved portion of the hull with its whaleback above the waterline. The term was never an official designation, but developed in common usage in response to the design's appearance when vessels were fully loaded. A total of 43 such vessels were constructed from 1887 to 1898. All but two were built initially as lake freighters for service on the Great Lakes of Canada and the United States. Six were built at Duluth, Minnesota; thirty-three were built at West Superior, Wisconsin; two at Brooklyn, New York; one at Everett, Washington; and one (without the designer’s approval) at Sunderland, England. A number of the Great Lakes vessels left the lakes for service on salt water seas.
The term "whaleback" has also been applied to a type of high speed launch first designed for the Royal Air Force during World War II, and to certain smaller rescue and research vessels especially in Europe that, like the Great Lakes vessels, have hulls that curve over to meet the deck. An example of the former is the British Power Boat Company Type Two 63 ft HSL. The designation in this case comes not from the curve along the gunwale, but from the fore and aft arch in the deck.
Yet another application of the term is to a sheltered portion of the forward deck on certain British fishing boats. It is designed, in part, so that water taken over the bow is more easily shed over the sides. The feature has been incorporated into some pleasure craft based on the hull design of older whaling boats, in which it becomes a "whaleback deck".
This article focuses attention on the historic whaleback vessels of the Great Lakes.
The whaleback was a design by Captain Alexander McDougall (1845–1923), a Scottish-born Great Lakes seaman and ship’s master. At the time a vessel’s size was limited by the locks and rivers that had to be navigated and by the materials and science of hull construction, not by the power and ability of steam engines to push hulls through the water. It was therefore common practice to have a powered vessel pulling one or more barges or “consorts” in tow. Many of these consorts were converted sailing schooners. Others were “schooners” that were built to be consorts and never intended to sail on their own, except in an emergency. Still others were bulk carriers that had not yet been fitted with propulsion machinery.
McDougall had learned from experience the difficulties encountered in towing these vessels. The bows and spars made them subject to the forces of wind, wave, and the prop wash from the towing vessel with the result that they often did not follow well. His purpose was specifically to create a barge design that would tow easily and track well.
When fully loaded, only the curved portion of the hull remained above the water, giving the vessel its “whaleback” appearance. Instead of crashing into the sides of the hull, waves would simply wash over the deck meeting only the minor resistance of the rounded turrets. When fitted with hawse pipes for anchors and a guide for the tow cable, the bow somewhat resembled the snout of a pig, from which came the alternate and usually derisive appellation of “pig boat”. The derision of scoffers notwithstanding, the design performed as McDougall expected. Whether towed or under their own power they were seaworthy vessels and fast for their time.
The remains of the Thomas Wilson lie just outside the harbor of Duluth, Minnesota. The Wilson was wrecked as a result of a collision with the George Hadley, which was inbound for the Duluth harbor at the same time the Wilson was departing Duluth. The wreck is listed on the National Register of Historic Places.
Some have claimed that the whalebacks were the prototype for the standard bulk carriers to follow. While certain design features were adapted to more traditional hull designs (most of the self-powered whalebacks were "stern enders"), the whalebacks cannot be said to be the prototypes of all to follow. They were a unique variation on a principle of design that started with the R.J. Hackett in 1869 and advanced with the Onoko (the second iron-hulled Great Lakes bulk carrier) in 1882. These principles included the consolidation of above-deck cabins at the extreme forward and aft limits of the hull to leave a large open area above the hold for both loading and unloading equipment, as well as a nearly box-like cross section to the hull to enable heavy cargos in shallow water.