 They encountered heavy flak and continuous fighter attacks . Owing to the delay , the ten @-@ ship convoy that they were sent to attack had departed two hours earlier , but there were still plenty of targets . Forty 500 @-@ pound ( 230 kg ) and twenty four 1 @,@ 000 @-@ pound ( 450 kg ) bombs were dropped from 8 @,@ 500 feet ( 2 @,@ 600 m ) . The mission claimed hits on nine ships , totaling 50 @,@ 000 tons . After the war , JANAC confirmed the sinking of only one Japanese merchant ship , the 5 @,@ 833 @-@ ton Keifuku Maru . Two other ships were damaged , as was the destroyer Tachikaze . Two B @-@ 17s were shot down , including Walker 's . 
