Estimating his position at about fifteen and a half leagues inside the Bank, which, according to his calculations, he entered at 45°30´ north latitude, Jean Marin Le Roy began looking for suitable fishing grounds. He sounded to determine at what depth the surface of the Bank was located, looking for the plateau that lies at a depth of 25 to 50 fathoms. In the mid-eighteenth century, pilots still located the Bank empirically: "The Bank measures at least 150 leagues from the northeast to the southwest, lying between 41° and 52° latitude, and about 60 leagues from the northwest to the southeast. Pilots estimate its longitude in relation to their ship's wake, supposing that there are 600 to 700 leagues in a straight line from the coast of France to the Bank, depending on where they are according to their charts." ⁶⁹

The ships that arrived at the Bank early, from January to March, fished between 43°30´ and 45° latitude. Those that arrived from May to August drifted between 45° and 47°30´.

Once the ship arrived at the Bank, and the winds and seas were favourable, the pilot's job was simplified. The daily manoeuvres became routine. The ship lay to, ⁷⁰ drifting slowly, trying to follow the schools of cod.

Following the recommendations of the Nouveau traité de navigation (New treatise on navigation) published in 1753, ⁷¹ Jean Marin Le Roy formatted his log as a roster, on which coordinates and other information are indicated clearly and methodically, sometimes accompanied by diagrams, to make it easier to consult. In fact, his charts go beyond the recommendations of the King's Hydrographer, Pierre Bouguer, who required twelve columns. They usually have fourteen columns. A record of the activities essential to the proper operation of the vessel and the fishery, the charts helped the pilot calculate the position and movement of the ship. They indicate the day of the week; the date; the number of hours the sails were set to starboard or port, furled or unfurled; the latitude observed at noon; the estimated latitude at 8 p.m.; the distance (in leagues) travelled in the 24 hours (also calculated at 8 p.m.); the nature and depth of the bottom of the sea; the weather; the direction (rhumbs), quality and force of the winds; and the number of cod caught each day. The last column of the charts contains notes on the ships encountered. Le Roy included the name of the captain to whom he spoke, the ship's home port, the number of cod caught and the date of the ship's arrival at the Bank. The number of ships that came into contact with each other on the vast triangular plateau ⁷² and the relations between the Norman captains are surprising. Le Roy mentions 42 captains (Table 1). The ships' mates often exchanged a few words, information and services, ⁷³ sometimes even dinner invitations!

From the day it got to the Bank to the last day of the fishery, the Saint-André drifted mainly between 44° and 46° north latitude, west of Jacquet Bank, remaining within 53 leagues of the entrance of the Bank.

The captain managed the activities on the Bank. He had to be well acquainted with the Bank fishery, know all the shoals and their position, be hardworking and patient, and not get discouraged if the cod was scarce. His ship had to be fully equipped for a six- to eight-month expedition, and the crew had to fish as much as possible. If the fishermen did not find cod in one area, the captain looked elsewhere, moving several times depending on the circumstances. When he found a good spot, he took advantage of it and required a maximum effort from the crew, both day and night. If a storm moved in, he had the yards lowered, the ship firmly anchored with two or three cables spliced together, and the hatches closed. The tiller was secured, and the crew waited for the weather to clear, sheltered inside the ship. ⁷⁴