History, my home discipline, has a reputation for relying less on robust theoretical constructs than its close relatives, such as anthropology. As the study of the past, it is free to study the past of any people, in any period, so long as there is language-based evidence to use as source material. That has been, traditionally, a defining limitation of the discipline. However, one of the major reading fields I undertook for my PhD in history was material culture studies. In earlier graduate training, I studied historical archaeology—the archaeology of people about whom we also have traditional historical—language—evidence. Some historians study art, some study medicine, some politics, language, etc.
Nevertheless, as with any academic discipline, history in practice does not tend to be as free as history in theory. A few strong fashions and foci rule most disciplinary territory at any given time. Funding follows fashion, and further encourages work in already-established areas of inquiry. Right now, for example, my discipline is preoccupied with the study of peoples historically marginalized from power relative to European males and their descendants: indigenous non-Europeans, Africans (especially enslaved Africans and their descendants), women, and those who were not strictly heterosexual and/or did not conform to widely- enforced gender norms. The table of contents of any major journal in the discipline will reflect this.
The discipline is also limited by the expertise of its practitioners. If a student pursues the humanities as an undergraduate, then undertakes and completes graduate training in history, that student has been rigorously-equipped to be a historian. But a historian of what? Certain areas of inquiry will prove challenging or even inaccessible to a historian without additional training and experience in areas of expertise outside the history department. For example, it would be difficult to be a historian of the development of cosmological precepts from Newton to quantum mechanics without a deep competence in physics. One would be hard-pressed to pursue the history of North African Bedouins without a strong command of their languages. History does, in fact, traditionally demand language competency from its practitioners, but it does not demand concomitant technical competence in other areas. I contend that technical extra-disciplinary competence is necessary to pursue promising avenues of intellectual inquiry in the humanities that are otherwise out of reach.
In the liminal zone between two fields in my discipline—the history of science and maritime history—is the history of navigation. In a survey of the state of scholarship in that field published in the International Journal of Maritime History, Willem Mörzer Bruyns observed that the subject would be well-served by more historians with technical competence in the subject. He could just as well have made the same point about economic historians writing about shipping: that they could pursue avenues of inquiry pertinent to their research questions if they possessed a sophisticated technical understanding of ships, without which such avenues would remain off-limits.
In my specialty of maritime history, as pursued within the parent academic discipline over the past three decades, the economic aspects of maritime activity have taken center stage; in fact, it was that very focus that brought the specialty into the academy in the first place. Older maritime history was generally non-academic and/or naval in focus. Maritime economic historians have pursued data-intensive research on the contributions of shipping to productivity and economic growth, from the early Middle Ages to the twentieth century. Such studies were part of a great flowering of econometric history, led by scholars just as competent in the economics department as on the history side, most famously Douglass North and Robert Fogel, who shared the 1993 Nobel Prize in Economic Sciences for their quantitative-history work on the early modern and modern western economies. Cliometrics, the use of formal economic theory, mathematical methods, and quantitative data to do historical research, contributed much to a more sophisticated understanding of the rise of modern economies. An important example was the work on “invisible earnings”—with shipping as a major component—in the British Atlantic economy of the seventeenth and eighteenth centuries. The work of North, his students James Shepherd and Gary Walton, as well as John McCusker and Russell Menard taught us that the economy of British America was largely based on its maritime commercial success, and thus could not be understood, as it had been, as a negative balance of payments vis-à-vis the British home islands. This in turn forced a re-evaluation of the economic contributors to the American Revolution.
That is where I work—but I am not an economic historian. I am a technological historian, and when we consider the technological aspects of shipping in maritime economic history, perhaps especially in the early modern period, we enter a liminal zone where there is still much to be done. It is here where the technical competencies of economic historians, technological historians, and ship archaeologists meet—and here where those competencies run out. It is also here where the considerable technical competencies of non-academics make a compelling case for relevance. These non-academics include experienced ship modelers, who base their work on careful, in-depth research; antiquarians, whose knowledge of a specific subject routinely exceeds that of academic historians in terms of technical detail; naval architects and marine engineers, who understand the principles of ship design as as no one else does; professional and volunteer mariners, who actually know how to operate replicas of early-modern vessels; and the shipwrights who know how to build and maintain those vessels.
It should be clear from that list that no one, no matter how dedicated or intelligent, can master all of those specialties in one lifetime—or even come close. Everyone who wants to work in that liminal zone will have a different set of competencies, but that set will by necessity cross disciplinary boundaries and will probably cross the street between the academy and the outside world as well. Everyone working in the zone who wants to make a contribution to scholarship must take advantage of what others in the zone have to offer. Collaborative effort, so central to scholarship in the natural sciences, must become much more common in history if the discipline is to exploit more areas of inquiry requiring technical expertise.
My work has two primary aims: first, to help answer questions about ship technology raised by the work of economic historians working on shipping productivity; and second, to contribute a more sophisticated understanding of period ship technology and of “pre-industrial” technology more broadly to the history of technology. Since I am not an economic historian, I am limited to the liminal zone of economic history in which period ship technology bears directly on their hypotheses and problems—which I am capable of understanding, thanks to my academic training. I did not read history of technology as a supervised field in graduate school. I began serious reading in it while researching my dissertation. Most of my subsequent study of it has been self-guided—but that’s self-guiding by someone with a doctorate in the discipline, so it’s not as though I’m not equipped to do that. With almost thirty years’ experience learning about sailing craft, the arts of navigation, and the nature of the sea—both inside and outside the academy, self-taught and formal—I have the technical understanding to interpret and present findings on ship technology to a historian or general audience. I do not, however, have the technical understanding of a naval architect, or of an archaeologist who has worked on ship design intensively. I work on acquiring as much as I can, but there is so much room in the liminal zone for naval architects, marine engineers, and technically-equipped archaeologists to contribute, ultimately, to economic and technological maritime history. I dream of an ongoing, productive, collaborative relationship with at least one such person. Meanwhile, a few of them have already contributed much to my work that I would not have had access to otherwise.
Maritime history is only one field in one discipline in which the liminal zone between traditional scholarship and extra-academic technical expertise promises so much to those who can bring both to bear. An accomplished musician has the potential to be the best historian of music. A trained architect has the potential to be the best historian of architecture. As more scholars come to doctoral study later in life, the potential may be there for us to benefit from more scholars like Jeff Bolster, who spent years running charter boats in the Caribbean before returning to the academy and putting out important work on life at sea.
It is also true, though, that some promising areas of the liminal zones will remain out of reach without a commitment to pursue collaborative relationships with those whose expertise overlaps but extends past one’s own in an important area. If we start seeing more scholarship published from work along the boundaries of fields and disciplines and vocations, we should expect to see more co-authors and multiple authors in the bylines. I hope we do.
 Willem F.J. Mörzer Bruyns, “Research in the History of Navigation: Its Role in Maritime History,” International Journal of Maritime History 21:2 (December 2009): 261—87.
 See W. Jeffrey Bolster, Black Jacks: African American Seamen in the Age of Sail (Harvard, 1997); and The Mortal Sea: Fishing the Atlantic in the Age of Sail (Belknap, 2012).