The Fenian Ram

Brayton Cycle-Powered Submarine Built to Fight the British Navy During the Fenian Movement

| September 2005

In 1999 I had the chance to visit the Paterson Museum in Paterson, N.J. It was a dreary, rainy weekday and I was passing through on my way to attend a conference at Stevens Tech in Hoboken. At this time I had been into the engine hobby about seven years.

As I toured the museum, I went to look at the "Fenian Ram," secretary of the Navy John Holland's submarine. The placard said it was powered by a Brayton cycle engine. Now my interest was piqued and I approached the curator, Bruce Balistrieri, and told him about my hobby and my interest in such an unusual engine. He asked me if I would like to climb inside and see it for myself ... I was in there for the better part of an hour.

The Fenian Ram

The Fenian Ram was designed by John Holland and launched in 1881. Upon first seeing his design, Holland proclaimed it as "a fantastic scheme of a civilian landsman." Holland's brother, Michael, had been introduced to the Fenian Movement, who sought Irish independence from British rule and had organized a skirmishing fund. The purpose of the fund was to build a three-man submarine to use against the British Navy. Work on Holland's boat started in May of 1879 at the Delamater Iron Works in Manhattan, N.Y., and was launched into the Hudson River two years later. The Ram's hull was 31 feet long and roughly 6 feet in diameter, with a shallow conning turret on top. Armed with a coaxial pneumatic "dynamite gun" in the bow, the 19-ton boat was intended to support a crew of three: a commander, an engineer and a gunner. The Ram was capable of nine knots, depths of 50 feet and stayed down for as long as an hour during tests, which took up to two years to complete. The Fenians, frustrated with Holland's delays and faced with internal legal squabbles, stole their own boat and hid it in a shed in New Haven, Conn., where it remained for 35 years. Holland had nothing more to do with the Fenians, and the boat was eventually donated to the city of Paterson, where it sits now.

A Unique Brayton

The Brayton cycle engine differs from the familiar Otto cycle in that instead of compressing the air/fuel charge and then igniting it, the Brayton cycle injects a compressed air/fuel charge into a cylinder where it is ignited and continues to be injected and burned for roughly half of the power stroke. After the air/fuel injection ceases, the remaining hot gases in the cylinder are allowed to expand until the bottom of the stroke is reached. Then an exhaust valve opens and the spent mixture is forced out of the cylinder. The Brayton cycle is referred to in engineering lingo as a complete-expansion diesel cycle, or Joule cycle. A modern jet engine is also called a Brayton cycle, but instead of pushing a piston, the compressed fuel/air mixture is burned and allowed to turn a turbine.

The Brayton engine in the Ram is a unique design. It has two tandem cylinders driven from both sides on the outside of a crosshead between them. The crankshaft has two throws in the same position. The front power cylinder operates off of compressed air generated by the rear cylinder, and a receiver stores the excess compressed air. Fuel is metered in the intake ports by small injection pumps. These pumps were crude by today's standards, employing a plunger and slide valve to direct the fuel to the cylinder. The valve mechanism, fuel pump and governor appear to be driven off of a toothed chain. On the top ends of the power cylinder are openings that I believe are for inserting either a preheated platinum sponge or a burning wick. In operation, the igniters are inserted in these ports and the air is turned on. The Brayton literally air started itself.

John Holland was clever in using a Brayton engine in his submarines, as the excess compressed air was probably pumped into large tanks in the front and rear of the submarine for blowing ballast and possibly operating the engine. I do not know whether the sub ran powered while underwater using the stored compressed air. If it did, I am sure it would not have traveled far since the pumping cylinders were capable of pumping the air tanks to 80-100 psi. The trail of bubbles from the sub operating under power would have been a dead giveaway as to its position.


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