was the "whaleback" design, which featured significant tumblehome in the sides of the hull and a rounded bow, looking rather like the back of a whale. Whereas the superstructure of an ordinary freighter had the bridge in the center of the vessel, beginning in the late 1800s lake freighters typically had the bridge and associated superstructure at the bow. Traditionally they had a second island, over the engine room in the stern. These dual-cabin boats were constructed between 1869 and 1974. R. J. Hackett premiered the style, and the second Algosoo was the final vessel designed this way. More recently built lakers, like CSL Niagara, have a single large superstructure island at the stern. Vessel speeds are not as important on the lakes as on the ocean. Ports are often closer together than in ocean trade, so cargo capacity is more important than speed. Lake vessels are designed with the greatest block coefficient to maximize the vessel's size in the locks within the Great Lakes/St Lawrence Seaway system. Therefore, ship designers have favored bluff bows over streamlined bows. After World War II, several ocean freighters and tankers were transported to the Great Lakes and converted to bulk carriers as a way to acquire ships cheaply. Several of them continue to sail today (e.g., Lee A. Tregurtha and a few others). Another distinguishing feature of lake vessels versus ocean vessels is the cargo hatch configuration. On the lake vessels, the hatches are traditionally spaced apart. This configuration was needed to match the hatches to the loading facilities. At the turn of the 19th century, most ore loading facilities had loading chutes spaced every . The ship designers used this pattern for their hatch configuration. This pattern continues today, even with modern lake vessels, therefore a lake vessel has many more hatches than an ocean vessel of equal length. The largest deep lock at the Soo Locks is Poe Lock which is long and wide. Because of size restrictions, there are currently thirty vessels on the lakes that can only pass between Lake Superior and Lake Huron using Poe Lock, although none approaches the lock's size. Many lakers are restricted to the Great Lakes, being unable to navigate the St Lawrence Seaway whose locks allow a maximum vessel size of in length and in breadth. The shallow draft imposed by the rivers (the controlling depths of in the St. Marys River and