Across the Indian Ocean and its enclosed seas, straits and bays, the ocean floor is littered with traces of its human past from previous centuries. Every year new shipwrecks or excavated boats in Sri Lanka, Indonesia, India, and Qatar (to name but a few!) add to a growing body of evidence for an interconnected, deep, cosmopolitan past for this oceanic arena. Taking the ship as object, in this talk I trace the disciplinary histories of these subfields between the natural and human sciences in the high imperial period. Using two figures who worked across the Indian and Pacific Oceans (James Hornell and Alfred Cort Haddon) between 1900 and 1940, I ask how boat design, maritime craft, and other seafaring techniques related to civilizational and racial orders were born in an era of high imperialism. In closing, I explore what it might mean for the contemporary fate of these disciplines  to grapple with these disciplinary histories.