For much of the late 19th and early 20th century, New York City maintained a fleet of ten fireboats.
In recent decades technology has improved to where smaller boats can provide the pumping capacity that required a large boat in the past.
[1] These smaller boats require smaller crews, and the crews themselves require less training.
Like many other cities the FDNY operates a fleet with a smaller number of large fireboats, supplemented by a number of unnamed boats in the 10 meter range.
[2]