I take the helm off a captain with a tide table

Nine metres of pilot ladder, rope and wooden steps, hanging down the side of a bulk carrier still making six knots. First thing about the job: the ship does not stop for me to climb. If it stops, it stops steering, and a ship that is not steering in a swell is a far bigger problem than me hanging off a rope.

The job is called harbour pilot and I have been one for eleven years. It consists of this: climbing aboard a ship you do not know, with a crew that does not know you, and taking it through a channel where there is no room for a mistake. Forty minutes of work. On the radio they call me by the call sign; the name, Maider Zarraluqui, gets used by two people a month.

That morning, at 05:40, the ship was called the Kestrel Anna and she was loaded with clinker. There was a north-westerly swell, a metre and a half, the kind that does not break but lifts the launch exactly when you put your foot down. I went up the nine metres without looking down, which is the only thing they really teach you, and at the rail the third officer, Marek Suchy, met me with a torch. "Careful, the fifth step," he said. The fifth step was snapped in half.

The captain was up top. Vasyl Omelchuk, forty-something, twenty-two years on bulk carriers. He did not give me the helm.

He was very polite. He offered me coffee, asked me about the swell, and did not move from the starboard side of the bridge, which is where the captain commands from. He showed me his phone with a message from the charterer. If the ship was alongside before seven, they collected a bonus; from one minute past seven, nothing.

I was asking him to come down to four knots to enter the channel. He was telling me, without telling me, that at four knots we would arrive at ten past seven.

I did not argue about speed. I took out the printed tide table, which I always carry on paper because paper does not run out of battery, and I put my finger on it.

"Captain, your draught is eleven metres twenty. At 06:20, at the mouth of the channel, you have ninety centimetres of water under your keel. At 06:50 you have a metre forty."

"Ninety centimetres is water."

"With a metre-and-a-half swell, the bottom rises and falls seventy-five centimetres under your keel. You do the subtraction."

"I know my own draught."

"You know your draught. I know the height of the water at the mouth at twenty past six."

"Two thousand two hundred dollars."

"Sorry?"

"The bonus. Two thousand two hundred dollars, and I am the one who loses them. You go home either way."

He stood looking at the table longer than he needed to. Then he took out his phone, photographed the tide page and sent it to the charterer with nothing written underneath. Then he took two steps to the left and gave me the place.

"Pilot has the conn," he said, loudly and facing the wheel.

"Pilot has the conn, aye," repeated the helmsman, Ruel Caraig, who had been four hours on watch and needed to hear out loud who was in command from that second on.

"If we are late, you write the email to the charterer," the captain told me.

"I write it."

We came in at four knots. We were alongside at 07:11.

The captain lost the bonus. I went down the same ladder two hours later, with the ship still this time, and before I left I gave him a photocopy of the tide tables for the next fourteen days, with the good hours marked in red.