Trying to set up a re-enactment of the Battle of Kuantan, in which Prince of Wales and the Repulse were sunk by a mix of Mitsubishi G4M's and G3M's flying out of their bases in Ho Chi Minh City/Saigon.
The CMO CW database has the Mitsuibishi G4M1 with a torpedo loadout having a strike radius of 160 nm.
From what I can make out in the literature, the torpedo-loaded G4M's had a strike radius in the order of 800-1000 nm, even with the heavier torpedo. In any case, as given from the approximate distance of the sites of the wrecks Prince of Wales and Repulse from Ho Chi Minh City, the strike ranges should be at least 380-400nm, and, based historical records, seems to be more than 600nm.
Here are some relevant quotes:
"The weather had improved greatly from the evening before, although scattered clouds were evident as the aeroplanes flew south. Meanwhile, Adm Phillips had abandoned his raid on Singora after his vessels were spotted the day before by Japanese cruiser floatplanes, Force Z instead now heading back to Singapore. A little after 1000, a Genzan Rikko flying the 3rd search sector finally found the British ships, and at 1015 it signalled, 'Enemy main force sighted. North Latitude 4 degrees, East Longitude 103 degrees 55 minutes. Bearing 60 degrees'.
Receiving this signal at Saigon, 22nd Koku Sentai immediately relayed the message to all units then in the air.
The aircraft of Genzan and Mihoro Ku all heard the first sighting report and headed immediately towards Force Z, but the men of Kanoya Ku, having flown farther south in their faster Type 1 Rikko, did not. By 1028 they were 600 nautical miles from base, and could see Singapore 80 miles to their right and the coast of Sumatra up ahead – but not Force Z. Reluctantly, they turned and headed back north."
Mitsubishi Type 1 Rikko 'Betty' Units of World War 2
-- Osamu Tagaya
Force Z shipwrecks of the South China Sea
pg 79.
at the time, British military thinking – based on the capabilities of their own torpedo-
carrying aircraft – accepted that the risk of aerial torpedo attack within 200 miles of enemy
airfields was great. But the risk of aerial torpedo attack was believed to decrease to almost zero
at a range of 400 miles – the limit of their conventional torpedo-bombers. British intelligence
at the time had no idea that the Japanese twin-engine bombers which had flown 600 miles
from indochina for the bombing raid on Singapore the night before could be easily re-armed
as torpedo-bombers. Their range in fact was 1,000 miles.
pg. 89
The ten squadrons of nells and Bettys flew in small formations of eight or nine aircraft,
and climbed slowly up to 10,000 feet. The visibility was excellent, with only small patches of
low cloud. The planes of six of the squadrons carried torpedoes, and the other four squadrons
carried bombs. They flew slowly south at their most economical speed – it was up to the nine
reconnaissance aircraft well ahead of them to the south to find the enemy and direct them in.
however, hours passed without word of force Z being located, and soon the bombers had
passed the danger-line of 400 nautical miles for their fuel supplies. Still, there was no report
of the British naval force, and the pilots started to become anxious about their fuel position.
