PT boats, for their size, packed considerable firepower. They usually carried two to four torpedoes – usually the 22.4-inch Mk 13 lightweight torpedo that was also dropped from aircraft. The PT boat was also equipped with two twin 12.7-millimeter machine guns. Later in the war, more weapons were added, including 40mm cannon, 20mm cannon, 37mm guns, rockets, and sometimes, even captured Japanese weapons. PT boats had a top speed of 74 kilometers per hour, and usually needed a crew of 17.
The Stiletto, on the other hand, carries no weapons. However, it can datalink with armed UAVs and aircraft, is stealthy, and can go much faster (92 kilometers per hour) while displacing 60 tons (compared to 38 tons for the 80-foot Elco PT). Stiletto can carry a dozen SEALs, and has a crew of three. It also had a draft of three feet.
Why the change? Part of this is mission requirements. Stiletto is a short-range insertion vehicle for special operations (using an 11-foot rigid-hull inflatable boat to actually put people on the beach), and has been supplied with a powerful computer network, making it readily adaptable for other missions, like reconnaissance and mine countermeasures. PT boats were designed for combat against transports, barges, and other forces. Some even attacked and sank destroyers and larger warships. Another part is technology. There were no PCs in World War II. The Stiletto's three-man crew will also have much better living conditions than the PT boat crews could ever imagine.
The PT boat and the Stiletto reflect different missions and different eras. The PT boat proved to be a very capable in its era, becoming known as the "devil boat" for its concentrated firepower, which accounted for many Japanese casualties in World War II. The Stiletto will be feared for its ability to deliver SEALs or other commandos in and out without being detected. Its only drawback is the price tag: $12.5 million for the first vessel. – Harold C. Hutchison (firstname.lastname@example.org)
The new 80-foot long, 60-ton Stiletto small craft, being tested for U.S. Special Operations Command, is fast, roughly the length of a World War II PT boat, and has a range of 800-900 kilometers. But speed, length, and range are the only things these two craft from different eras have in common. Both are very different otherwise, a reflection of the times they were built in, and the missions they are intended to carry out.