For the first 18 years of their collaboration, Heezen collected bathymetric data aboard the research ship, the Vema, while Tharp drew maps from that data since women were still excluded from working aboard ship at that time.
Durante os primeiros dezaoito anos da súa colaboración, Heezen recolleu datos a bordo do barco do observatorio, o Vema, e Tharp trazou mapas a partir deses datos, posto que as mulleres naquela época aínda estaban excluídas do traballo a bordo dos barcos.