FJ is the common name given to the dinghy called a Flying Junior. In their original form they had spinakers and trapezes. Now they are primarily used in college sailing competitions in the U.S. where they used with just main and jib, making them very simple boats. Their specifications are:

The FJ is a very popular choice for college sailors because it is a very tactical boat, because it is easy to tack and it points very close to the wind. This is in contrast to the 420 which is slower to tack, and points lower.