Martin PBM Mariner - overview forum
XPBM-1 - prototype of a four-engine patrol flying boat, 1 pc
PBM-1 - first series, engines R-2600-6, 20 pcs
XPBM-1A - XPBM-1 modified for armament tests
XPBM-2 - prototype with auxiliary tanks and the possibility of ejection
PBM-3 - second serial version with R-2600-12 engines, 32 pcs immediately converted to PBM-3R
PBM-3B - designation US Navy for 28 PBM-3C s British equipment, at the RAF marked Mariner GR Mk.I
PBM-3C - patrol variant PBM-3
PBM-3D - second patrol variant PBM-3, standard radar equipment, reinforced armament and armor
XPBM-3E - prototype for radar equipment tests
PBM-3R - transport variant PBM-3, 50 pcs including converted PBM -3
PBM-3S - specialized anti-submarine variant
XPBM-5 - prototype of a new variant with a more powerful engine
PBM-5 - third serial version with R-2600-22 engines
XPBM-5A - PBM-5 converted to prototype amphibious version
PBM-5A - amphibious variant
PBM-5E - designation for PBM-5 equipped with better radar, in practice not used
PBM-5G - 24 PBM-5 converted to USCG rescue machines
PBM-5M - machine adapted for monitoring missile tests
PBM-5N - machine adapted for all-weather operation
PBM-5S - a certain number of machines adapted for specialized anti-submarine
PBM-5S2 - anti-submarine modernization from the Korean War
Source: aeroweb.brooklyn.cuny.edu