鈴谷「輸送作戦順調だねぇ。やっぱ鈴谷達が5-4で熟練度上げまくったドラム缶積んでるからだね！」

Suzuya: The transport operation is looking good isn't it. It's definitely because Suzuya and the others keep on increasing our skill level by going on a drum run at 5-4!

Carrying drums on your fleet at World 5-4 is an easy level grinding method, especially for heavier ships like CA and BB.