The signal SSS signaled attacked by submarines , whilst RRR warned of an attack by a surface raider , QQQ warned of an unknown raider ( usually an auxiliary cruiser ) , and AAA indicated an attack by aircraft .
The signal SSS signalled attacked by submarines , whilst RRR warned of an attack by a surface raider , QQQ warned of an unknown raider ( usually an auxiliary cruiser ) , and AAA indicated an attack by aircraft .