Normally the stylus-shaped marine antennas, but not those for installation in the masthead, have a 1" x 14 thread at the base, where the first number identifies that the diameter is one inch (2.54 cm) and the other that the thread is composed of 14 threads per inch.
It is common for VHF, CB, AIS, TV, HF, WiFi, multiband marine antennas and sometimes can also be found in external FM and GPS antennas. In the nautical market are widespread bases with such attachment that can be for mounting on flat surfaces, on pulpit or bulkhead.