Power at Sea: Insights from a Naval Power Dataset, 1865-2011

Brian Benjamin Crisher and Mark Souva, Florida State University

Naval power is a crucial element of state power, yet existing naval datasets are limited to a small number of states and ship types. Here we present 147 years of naval data on all the world’s navies from 1865 to 2011. This country-year dataset, which we will publish in a forthcoming article in International Interactions, focuses on warships with ship-based weapons capable of using kinetic force to inflict damage on other structures or peoples. After identifying a country’s active naval forces, we create a measure of naval power based on the aggregate tonnage of the active ships. Additionally, we create count variables for ship types such as aircraft carriers or battleships. This summary paper introduces the country-year data, describes variables of interests and suggests potential questions of interest scholars could explore using the naval power dataset.

Despite the prominence of naval power and its importance for understanding foreign policy and international interactions, the academic community lacks a dataset on each state’s naval capabilities. Modelski and Thompson (1988) is the most commonly used naval data set, yet their data is limited to the great powers, only includes one or two ship types in a given period, and ends in 1993.(While the data presented by Modelski and Thompson (1988) ends in 1993, the last five years of data are actually estimates based on knowledge of construction plans in 1988, see Modelski and Thompson 1988, 90).Here we present a much larger dataset of naval power for the years 1865-2011. We present data on all of the world’s navies, not just the great powers. For these years we code data on 73 countries. In addition, our dataset includes information on a larger number of ship types, including but not limited to dreadnoughts, battleships, aircraft carriers, diesel submarines, nuclear attack submarines, and nuclear ballistic missile submarines. Armed with such expansive data we are able to construct a much clearer picture of the world’s navies and changes in naval power over time. Furthermore, this new data allows us to create a new annual measure of state naval strength, which we believe will be of interest to many researchers.

To create an annual measure of state naval strength, we focus on ship tonnage. Ideally, a measure of state naval power would count all ships and have a perfect assessment of each ship’s ability to inflict damage on an adversary’s territory or weapons systems as well as operate in conjunction with other ships for these purposes. Such an assessment would consider a ship’s displacement, weapons systems, total firepower, speed, armor, maneuverability, communication systems, etc. Unfortunately, such an assessment is not possible. The variation among the many warships traversing the world’s waterways both past and present is too great and the multidimensionality of this ideal power measure is too great for an analyst to reduce it to a single number.

Notwithstanding the multidimensionality of naval power and the complexity of large-scale naval operations, we propose that a useful approach to gauging state naval power is to calculate the total tonnage of a country’s primary warships. Such a focus is not without precedent. The Washington Naval Treaty of 1922 uses displacement tonnage as its primary criterion for limiting the size of each state’s navy. Additionally, in the conflict literature, Lemke (2002, 149) uses warship tonnage in order to define the military reach of countries – countries with ten ships of 10,000 tons are considered to have global reach and countries with ten ships of 1,000 tons are considered to have regional reach.

Scholars should however be mindful of the limitations of such a decision when using this data in future research. The aggregate tonnage of a state’s navy may tell us about its overall strength, but it will not tell us how well their navy will perform in a combat capacity or whether their navy is qualitatively better than a navy of comparable tonnage. An alternative approach could focus on weapons systems. To this end, one might sum the number of guns on all ships in a state’s inventory. However, basing a measure solely on the number of guns fails to acknowledge that not all guns are equal. Around the turn of the twentieth century, one would find some ships with 12-inch guns while others with 8-inch guns. The introduction of the submarine (with torpedoes), aircraft carriers (with aircraft), and missile technology make an exclusive focus on weapons systems less useful. As such, we focus on tonnage.

While deciding on what characteristic of warships to focus on is crucial for determining a country’s naval power, also crucial is deciding what ships to include in the dataset. Should we follow the path of Modelski and Thompson (1988) by only focusing on the largest of warships, generally referred to as capital ships? Or, should we include every naval vessel in a country’s inventory from the largest aircraft carriers down to the smallest patrol boats? We believe the answer lies between these two extremes.

We argue that a valid measure of state naval power, particularly for smaller countries, will include more than just capital ships. At the same time, it is not practical, and probably not helpful for most research questions, to record every single naval vessel. Choices have to be made. We chose to focus on ships that can utilize ship-based weapons to destroy land, sea, or air targets outside of their own littoral waters. To this end, we code ships and/or ship types based upon minimum tonnage and weapons criteria that change as the prevailing naval technologies of the time change. In other words, we examine the last one hundred and forty-seven years of naval history to identify qualitative changes in naval technology affecting a minimum threshold for inclusion in the data.

To mark changes in naval technologies, we break down the years included in our dataset into naval periods. A new naval period occurs with the emergence of a new war fighting technology that gives the actor with the technology a significant military advantage in head-to-head combat. In other words, a new naval period occurs when the most dominant type of warship in the previous year is no longer dominant in the current year. For example, a pre-Dreadnought battleship is not the most capable ship type in 1910 (the super-Dreadnaught class battleships are the most capable) but compared to the premier warships twenty years earlier, it is at least as capable. Drawing on the ‘Conway’s All the World’s Fighting Ships’ (Chesnau and Kolesnik 1979; Chesnau, 1980; Gardiner and Gray, 1985; Gardiner, Chumbley, and Budzbon, 1995), and Modelski and Thompson (1988), we identify four naval periods.

Our first period extends from 1865 to 1879. Because of the great variation in ship designs in this period, we record all ships that displace at least 1,000 tons. Around 1880, the pre-Dreadnought emerges as the dominant warship. This begins our second period that extends through 1905. Here we increase our minimum criteria to at least 2,000 tons displacement and a primary gun of 5-inches or greater for a ship to be recorded. Period three covers the years 1906 to 1946 and is a period of new naval technologies such as the aircraft carrier and submarines. As such, we record all aircraft carriers and all submarines. Additionally, we record all non-carrier surface warships with at least 2,000 tons displacement and 5-inch guns, or ships with 1,000 tons of displacement and at least 3 torpedo tubes. Period four covers 1947 to the present and we record information for submarines that displace more than 1,000 tons submerged (nuclear and non-nuclear alike), frigates, destroyers, cruisers, assault ships, and aircraft carriers.

Finally, to create an annual measure of state naval strength we sum together the tonnage of the individual ships identified throughout the various naval periods. With the measure of state naval strength we are able to create another variable of interest. Specifically, we adopt a procedure similar to how the Correlates of War Composite Indicator of National Capability (COWCINC) is calculated (Singer, Bremer, and Suckey, 1972). First, we sum the total naval tonnage for all states in the system for each year. Then, we calculate each state’s proportion of tonnage in the system.

As we move deeper into the twenty-first century, naval power will continue as a key topic in the international community. This article introduces a new dataset on naval power that can help us understand the relationship between naval power and numerous political phenomena. The naval power dataset we present here includes six variables – state naval tonnage (continuous), state tonnage proportion (continuous), aircraft carriers (count), battleships (count), diesel submarines (count), and non-ballistic nuclear submarines (count) – measured annually from 1865-2011. The expansive spatial domain of our dataset allows scholars to apply naval power to studying the actions of major and minor powers alike. Additionally, the temporal domain of the dataset allows for studying contemporary issues as well as historical ones. We believe scholars will find this data helpful as they seek insights into numerous topics in international relations and foreign policy.

Literature and Further Reading

Crisher, Brian and Mark Souva. Forthcoming. Power at Sea: A Naval Power Data Set, 1865 – 2011. International Interactions.

Chesneau, Roger, and Eugene M. Kolesnik. 1979. Conway’s All the World’s Fighting Ships,1860-1905. London: Conway Maritime Press.

Chesneau, Roger. 1980. Conway’s All the World’s Fighting Ships, 1922-1946. London: Conway Maritime Press.

Gardiner, Robert, Randal Gray. 1985. Conway’s All the World’s Fighting Ships, 1906-1921. London: Conway Maritime Press.

Gardiner, Robert, Stephen Chumbley, and Przemysaw Budzbon. 1995. Conway’s All the World’s

Fighting Ships, 1947-1995. Annapolis: Naval Institute Press.

Lemke, Douglas. 2002. Regions of War and Peace. Cambridge: Cambridge University Press.

Modelski, George and William R. Thompson. 1988. Seapower in Global Politics, 1494-1993. Seattle: University of Washington Press.

Singer, J. David, Stuart Bremer, and John Stuckey. 1972. “Capability Distribution,

Uncertainty, and Major Power War, 1820-1965.” in Bruce Russett (ed) Peace, War, and Numbers, Beverly Hills: Sage, 19-48.

About the Authors

Brian Benjamin Crisher is PhD candidate at Florida State University. His research examines the influence of military power on conflict processes. His current research examines how military capabilities create uncertainty about the cost of military conflict and lead to bargaining failures.  Email: bcrisher@fsu.edu.

Mark Souva is an Associate Professor of Political Science at Florida State University. His research examines how domestic political institutions influence international interactions, particularly crisis bargaining, the use of and responses to military force and economic sanctions. His current research analyzes why some arms races but not others contribute to the outbreak of war. Email: msouva@fsu.edu.