A Bimini top attaching system has a mounting bracket that is affixed to a watercraft and a latch affixed to a frame tube. The latch has a main body with a tube portion that is located inside the tube and a hook portion that is exposed. The latch includes a movable catch that slides inside a catch trough between a locked and unlocked position, with a spring biasing the catch towards the locked position. In the locked position, a chisel point on the catch interrupts a transverse notch in the hook portion. Moving the catch to the unlocked position allows a pin on the mounting bracket to pass in and out of the transverse notch. The catch is restrained in the catch trough when the tube portion is located inside the tube.