The Japanese air strike was launched at a range of 600nm and did not include any fighter escort. Orbat here. Japanese torpedo bombers were lightly constructed and lacked armour and self sealing tanks. The G4M Torpedo bomber was given the Allied reporting name of Betty. The Japanese nickname was the Cigar: US pilots called it the flying Zippo.
Force Z was in coastal waters and air cover could have been provided and was offered. Even a handful of F2A Brewster Buffalos would have shot down inflammable G4Ms trying to attempt a torpedo attack flying a steady course at 150 kts and 100ft altitude.
[i]Phillips did not believe that the
RAF and other Allied air forces could guarantee
air cover for his ships,[
citation needed] as they had only limited numbers of
fighters.[[i]
citation needed] However, one squadron,
No. 453 Squadron RAAF with 10
Brewster F2A Buffalos at
RAF Sembawang, had been designated "Fleet Defence Squadron", to provide close cover for Force Z.
[23] The squadron's acting CO, Flight Lieutenant
Tim Vigors, had been advised of the radio procedures that would used by Force Z.
[24]
Despite his misgivings about the air cover available, Phillips elected to proceed. It is believed that four factors entered into his decision: he thought that Japanese planes could not operate so far from land, he believed that his ships were relatively immune from fatal damage via air attack, he was unaware of the quality of Japanese aircraft and
torpedoes,
[23] and like many Royal Navy officers, Phillips underestimated the fighting abilities of the Japanese...
...No. 453 Squadron RAAF, which was to provide air cover for Force Z, was not kept informed of the ships' position. No radio request for air cover was sent until one was sent by the commander of
Repulse an hour after the Japanese attack began. Flight Lieutenant Vigors proposed a plan to keep six aircraft over Force Z during daylight, but this was declined by Phillips. After the war, Vigors remained bitter towards him for his failure to call for air support on time.
[24] He later commented, "I reckon this must have been the last battle in which the Navy reckoned they could get along without the RAF. A pretty damned costly way of learning. Phillips had known that he was being shadowed the night before, and also at dawn that day. He did not call for air support. He was attacked and still did not call for help."
[29] Daytime air cover off the coast was also offered by Wing Commander
Wilfred Clouston of
No. 488 Squadron RNZAF, but his plan, "Operation Mobile", was also rejected.
[30]wikipedia
Had Phillips accepted the RAF offer the course of the war might have been a little different. Even just six defending fighters might have cut down a dozen or more bombers and spoiled the aim of enough of the bombers to save the captial ships.
At the very least the defence of Malaya would have kicked of on a higher note.