Abstract: A releasable boom lock located between a swing tower that pivotally supports a boom consists of a latch pivoted on the swing tower and a pin located on the boom. The pin and latch are designed to automatically interlock the boom and swing tower when the boom is moved to a transport position and are separable from each other by manipulation of a tool fluid ram pivotally supported on the boom. The tool fluid ram has an extension held in a fixed position so that operation of the fluid ram, which causes it to pivot on the boom, will move the extension into engagement with the pivotable latch and release the boom from the swing tower. The extension can be released to be pivotable on the ram to allow operation of the ram without releasing the latch.