Tuna's report exposes the insertion problem

Preliminary trials showed that assembling and disembarking the kayaks could expose Tuna on the surface for close to an hour. Rees therefore balanced submarine safety against the raiders' need for an accurate position and a favorable tide into the Gironde. Aircraft, a patrol trawler, coastal searchlights, and RAF mines laid in awkward positions forced him to abandon the original approach and surface closer to shore. Tuna's upper-deck party still put five assembled boats into the water in about forty-three minutes, giving the raid a precise operational record as well as a successful launch.