The commitment of the treasuries of Spain, France and England to their Navies was gradually increased as the eighteenth century progressed. The will of these three enlightened states to carry out the correct management of naval resources extended to the decks of the ships, where those in charge of the economy on board were also responsible for the accounting. The purpose of this paper is to understand how the work of the onboard accountants was carried out and how it affected the ship’s environment, how they attained the position, which tasks were entrusted to them, what records were made and how and to whom they rendered accounts. The study will be carried out through a comparative analysis of the main regulations. The conclusion is that although the onboard accountants have similar functions in all three cases, the way in which the roles were successfully carried out in each country was very different.