|The O'Brien is powered by a triple
expansion steam engine. It makes 2,400 HP at 76 rpm and drives one screw.
is one of the few working examples remaining of a triple expansion marine steam engine.
The powerplant is fired up during the third weekend of each month, should you wish
to see it in operation.
The design was common at the turn of the century but was eventually replaced
by more efficient steam turbines.