Not going to write your paper for you, but you should look up Joseph Inikori's critique of Curtin and also look at the work of David Eltis and others to update Curtin's work and construct a database of all known voyages during the slave trade. Much of that work is collected at the website www.slavevorages.org, which includes fine-grained data on the slave trade and also has a number of essays describing the project and the methodological issues involved. There is also an edited volume, entitled Extending the Frontiers, edited by Eltis and David Richardson, on the uses of the new database. Paul Lovejoy has been a major critic of the accuracy of the database project, including in this article: http://mwbdvjh.muse.jhu.edu/journals/journal_of_interdisciplinary_history/v040/40.1.lovejoy.pdf

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