Part 1 Bombed at sea
While en route from Singapore to Rangoon, the US and Dutch POWs were part of a three-ship convoy. The convoy came under a bombing attack by US B-24s, probably flying out of Indian. One of the transports (Dai Nichi Maru) carrying many Dutch Prisoners and the accompanying Destroyer were sunk (no Americans were on that transport). The ship carrying the US POWs (Dai Moji Maru) was hit in the stern and damaged but continued on to Burma. By the time they approached the port, the ship was listing badly so the guards herded the prisoners to one side of the ship in an effort to correct the list.
Part 2 Bombed on land
In his account of his time on the TBR, Army 1LT Fillmore gives a vivid account of the bombing raids that Allied bombers made on the two bridges at Kanchanaburi (which he denotes as Kanburi). His is the first account that I have seen that described that indeed both bridges were destroyed but that the original wooden bridge was quickly repaired. According to his story, the railroad operated more or less at full capacity carrying supplies to Burma and evacuating wounded from Oct ’43 until Jan ’45 when the number of bridges destroyed by bombing was beyond the capacity to repair. The bombing was so inaccurate that bombs frequently fell on the POW camp near the bridges. Luckily there were few casualties (no US POWs were killed) but the threat was such that some were moved across the river to the ChungKai hospital camp for safety.