In the early 1910s, only a dozen years after Holland inaugurated the Navy's undersea force, naval strategists had already begun to wish for submarines that could operate as long range reconnaissance vessels, in closer collaboration with the surface fleet than the Navy's existing classes, which had been designed primarily for coastal defense.

In the ensuing authorization of eight submarines, Congress specified that one should "be of a seagoing type to have a surface speed of not less than twenty knots."

Although Schley and two sister boats authorized in 1915 - AA-2 (later T-2), and AA-3 (later T-3) - initially all made their design speed of 20 knots (37 km/h; 23 mph), they could only maintain that speed for short periods of time before extreme torsional vibration problems with their tandem engines forced them to slow.

One NELSECO four-cycle four-cylinder auxiliary diesel generator was included to charge batteries while the main engines were operating at high speed.

From 1923 to 1927, T-3 was re-engined with two German-built Maschinenfabrik Augsburg Nürnberg AG (MAN) four-cycle ten-cylinder diesels, 2,350 hp (1,750 kW) each.

[16] They were based out of Hampton Roads, Virginia as part of Submarine Division 15 in the Atlantic Fleet and were used for training and maneuvers.

Between 1925 and 1927, T-3 was restored to service in order to test German-built diesels (2,350 hp (1,750 kW) MAN engines), then returned to Philadelphia.

This article incorporates text from the public domain Dictionary of American Naval Fighting Ships.