Kammala jumla mai zuwa: De Neumann ya fara haɓaka tunani game da yuwuwar tsarin kula da tashar jiragen ruwa yayin da yake kyaftin din HMRC "Vigilant". Waɗannan ra'ayoyin sun biyo bayan la'akari da irin waɗannan abubuwan da suka faru kamar haɗarin haɗari na jirgin ruwa na HMS "Divina" a 1950, jirgin ruwa na Norwegian "Baalbek" ya haɗu da sansanin soja na Nore a 1953, da kuma bala'in
Ambaliyar Tekun Arewa wanda ya haifar da ambaliyar tsibirin Canvey, Foulness da Gabashin Gabas a 1953. A cikin waɗannan da sauran yanayi, ceto da kuma tattara bayanan sirri sun kasance da matukar damuwa ta hanyar rashin kulawa da kulawa, wanda ya haifar da rashin fahimtar halin da ake ciki.