In discussing their situation, Charlie mentions to Rose that the Germans have a gunboat, the Queen Louisa (actually Königin Luise in German), which patrols a large lake downriver, effectively blocking any British counter-attacks. Rose comes up with a plan to convert the African Queen into a torpedo boat, and sink the Queen Louisa. Charlie points out that navigating the river would be suicidal: to reach the lake they would have to pass a German fort and negotiate several dangerous rapids. But Rose is insistent and eventually persuades him to go along with the plan.