The self-unloading schooner-barge Transfer began its career as the William McGregor. The schooner-barge was launched in 1872 at the Linn & Craig shipyard in Gibraltar, Michigan. The vessel was first enrolled at the port of Detriot, Ohio under the official number 80268. The vessel was described as having one deck and three masts measuring 200 feet in length, 33.9 feet in beam, and 13.7 feet in draft with a carrying capacity of 732.94 tons.

The William McGregor was built for the Northwestern Transportation Company of Detroit and was purposely built to be towed by the steamship R.J. Hackett, what is arguably the firs purposely built bulk freighter, in the bulk cargo trade.

for thirty-eight years the schooner-barge engaged in carrying iron ore between Lake Superior mines and Lake Erie pors, until 1911 when it was sold to the Milwaukee-Western Fuel Co. of Milwaukee. After it's purchase the vessel was renamed Transfer, rebuilt as a tow barge, equipped with self-unloading machinery, and used specifically in Milwaukee's riverways transporting coal between coal yards and powerhouses. In 1915 the Transfer was purchased by the Milwaukee Electric Railway and Light Co. and used to transport caot to the company's powerhouses, the Commerce street plant, Oneida street plant, and Commonwealth plant. Durint its twelve-year service as a coal barge Transfer made 1,525 round trips between coal docks and power houses carrying a total of around 1,830,000 tons of coal.
In 1923 the Milwaukee Electric Railway and Light CO. decided to purchase another vessel, the Collier and retire the Transfer. The vessel was removed of anything of value and towed six miles out of the harbor where it was cast adrift and rammed three time until it sank under the water.
The Transfer shipwreck site was located by Captain Jerry Guyer. Society maritime archaeologists surveyed the site in August 2019.

The remains of the self-unloading schooner-barge lie broken on an even keel in 120 feet of water, 6.0 miles southeast of the main Milwaukee harbor entrance in Lake Michigan. the vessel remains broken, though most of it's construction components and artifacts remain within the vessel's broken hull. The wreckage sits relatively flat on the lake bottom. the starboard side is flayed outward and the port side has collapsed on itself covering a portion of the wreck. the sternpost still stands 11.0 feet off the bottom of the lake. Because of the terms of its sinking, there is a lot of disarticulated timbers all over the site.