Princess May was built and launched under the name Cass in Hebburn, on the south bank of the River Tyne in North East England, in 1888 by Hawthorn, Leslie & Co., Ltd. for the Formosa Trading Company.

[2][3] Hawthorn Leslie built another ship, the Smith, at the same time for the Formosa Trading Company.

[2] The arrival of Cass and Smith at Taiwan was called the “shipping event of the year” for the China coast.

A contemporary source states that the ostensible purpose of ordering the two steamers was modernization of Taiwan, but the actual goal was to compete with the China Merchant Steam Navigation Company and its two allied English companies for the passenger traffic on the Yangtze River and between Shanghai and Tientsin.

[6] In 1901, the newly formed Canadian Pacific Railway Coast Service, operating in British Columbia under superintendent James W. Troup, wanted a steamship to meet the high demand for traffic on the route to southeastern Alaska, but did not want to wait for a year or more to build a new ship.

[2] Princess May was the first ship acquired by then-newly formed Canadian Pacific Railway Coast Service.

[2][8] At this time, the demand for fast travel to Skagway was high, and steamships, including Princess May competed with each other to see which could first reach the port.

[9] On 5 August 1910, Princess May, having departed from Skagway under the command of Captain MacLeod with 80 passengers, 68 crew, and a shipment of gold, was proceeding south down Lynn Canal in heavy fog.

At a speed of about 10 knots (19 km/h), the ship ran aground on rocks near the north end of Sentinel Island, where there was a United States lighthouse station.

It was high tide (the tidal range being about 16 feet (4.9 m) at this point) and the momentum of the ship forced it well up onto the rocks, with the bow jutting upward at an angle of 23 degrees.

The wireless operator, W.R. Keller, did not have time to send out a distress call before the main power was lost.

Temporary shipways were built and rocks were blasted, and after several previous attempts failed, on 3 September 1910, the salvors were able to refloat the ship and tow it to port.

In 1911, while undergoing repairs from the Sentinel Island stranding, Princess May was converted from coal to oil fuel.