The Tide Table’s Small Print

The ferry was due at ten past nine. At twelve past nine, it was still sitting on the mud.

This was not, strictly speaking, the ferry’s fault.

It was a square little vessel with peeling blue rails and the practical expression of something accustomed to carrying bicycles, shopping and one regrettable goat. A narrow channel ran from its berth towards open water. Most of the channel presently looked like wet slate.

The operator, Len, stood beside a chalkboard that said NEXT CROSSING 9:10. He added a question mark.

“Very official,” I said.

“It’s maritime punctuation.”

There were five of us waiting: a woman with two sacks of flour; an elderly man holding a violin case; a father named Owen; his daughter Beth, who was nine and had made a paper boat from the ferry leaflet. I had no urgent reason to cross. This placed me in the unusual position of being the calmest person there.

Beth set her boat in a puddle. The wind turned it around and sent it back to her shoe.

“It knows something,” she said.

Len had expected enough water over the sill by nine. The tide table agreed with him. The harbour did not. An offshore wind had been blowing since before dawn, pushing surface water away from the inlet. The predicted tide had arrived as an astronomical event. The useful water had not arrived as a transport service.

Owen checked his watch. “But high tide’s at nine fourteen.”

“At the gauge outside the harbour,” Len said. “And that’s a prediction.”

He said prediction the way cooks say serving suggestion.

Beth looked at me. “Can the Moon be late?”

“The Moon is extremely reliable,” I said. “It’s the coast that improvises.”

That required some explaining.

Tides begin with the gravitational effects of the Moon and Sun, but a tide table is not a diary kept by either of them. At a measured location, years of water-level observations can be separated into repeating components called harmonic constituents. Each has its own amplitude and timing. Add the curves together and you get a useful prediction of the astronomical tide.

The largest lunar constituent in many places is called M2. Because Earth turns while the Moon moves along its orbit in the same direction, a place on Earth takes roughly twenty-four hours and fifty minutes to face the Moon in the same way again. M2 produces two peaks in that interval. The largest solar constituent, S2, has two peaks in twenty-four hours. There are more curves, naturally. The universe dislikes giving a straight answer when thirty-seven cosines will do.

Beth considered this.

“So the table is lots of waves added together?”

“Yes.”

“And the wind didn’t sign it?”

“Exactly.”

Len tapped the chalkboard. “I’m stealing that.”

Official predictions can account beautifully for the repeating astronomical parts and still be defeated locally by wind, air pressure, rain, river flow and the shape of a shallow harbour. A narrow inlet can delay water. A funnel-shaped bay can enlarge a tide. A hard wind can pile water against a coast or move it away. The Moon may keep its appointment while the sea gets caught in traffic.

The flour woman, whose name was Priya, lowered her sacks onto the bench.

“How long?”

Len crouched at the edge of the berth and read the water against a row of painted marks. “Could be twenty minutes. Could be forty.”

The elderly man opened his violin case, which made everyone look alarmed. It contained no violin. Inside were three loaves of bread, a jar of screws and a red woollen hat.

“Better insulation than a shopping bag,” he said.

His name was Tomas. I decided not to ask where the violin was. Some questions deserve the dignity of remaining decorative.

Beth’s paper boat left the puddle in a gust and skated across the concrete towards the channel. I put out a boot. It struck the toe, changed course and vanished under the ticket hut.

“I saved it,” I said.

“You made it worse.”

“That is a more exact description.”

The gap under the hut was too narrow for my hand. Len produced a boathook far too large for the task. Priya contributed a wooden flour scoop. Tomas offered a screwdriver from the violin case. Within a minute we had assembled a rescue operation whose equipment outweighed the casualty by several thousand to one.

I lay on the boards and looked underneath. The boat had lodged against a cable. Beside it, the wind had collected two leaves, a bottle cap and what appeared to be every receipt issued by the harbour since Tuesday.

“Can you reach?” Beth asked.

“Yes,” I said, which was optimistic.

I extended the flour scoop with the screwdriver taped to its handle. The tape came from Len. The first attempt pushed the boat farther away. Beth made a small sound of professional disappointment.

“Perhaps less confidence,” she suggested.

I tried again with less confidence. It worked.

The boat emerged slightly crushed and carrying a dead leaf as cargo. Beth accepted it without ceremony, repaired the bow with a strip of tape and wrote WIND on the leaf.

While we had been occupied, the water had crept over the first painted mark. It did not arrive as a wave. It appeared in seams between stones, around the ferry’s hull and along the black ribs of the channel. The offshore wind still worried the surface, but the rising tide had begun to win by persistence.

Len measured twice more. Priya bought tea for everyone from the kiosk. Tomas removed the red hat from the violin case and put it on, thereby resolving one mystery and improving the harbour by several degrees.

At nine forty-one, the ferry floated free.

Len erased the question mark and changed the board to 9:45. He let Beth carry her paper boat aboard, provided it travelled in her pocket. Priya’s flour went under cover. Tomas’s bread retained first-class accommodation. Owen stopped checking his watch.

I stood at the stern as we moved through the channel. On the rocks, the wet line rose and fell with every small wave, untidy around the larger, slower rise. Prediction and weather were both present. Neither had cancelled the other.

Halfway across, Beth stood beside me and unfolded the leaflet. Her boat had become a page again, though a wrinkled one.

“Will it be late tomorrow?”

“The tide will be later,” I said. “The ferry may surprise us.”

She wrote that beneath the timetable.

On the far side, Len tied up and gave me back the flour scoop, which I had somehow carried across the harbour.

“That belongs to Priya,” he said.

Priya was already walking up the hill with both sacks.

I ran after her.

The Moon had done its work. The wind had done its work. I had done mine and stolen a kitchen utensil.

Of the three, I was the only one required to apologise.