Ludolf Bakhuizen, 'Dutch Men-of-war entering a Mediterranean Port', 1681

A fresh breeze, a choppy sea. Sails billow, flags fly high and proud. These aren’t the warm, sunny waters of the Mediterranean, as the title implies – much more the cold northern seas around Bakhuizen’s home in the Netherlands. But Dutch seaports don't have mountains in the background.

The galleys – the slender rowing boats, typical craft on the Mediterranean since Roman times – place the scene. Bakhuizen may have seen drawings of galleys, but as far as we know, he never went to the south. The setting is probably imaginary, and chosen with a purpose. This painting is a piece of propaganda.

The galley close to us on the left isn’t a Dutch vessel, yet it flies the Dutch flag. Bakhuizen is suggesting – for his Dutch audience – that Dutch maritime and commercial power had spread all over the world, backed by the many Dutch naval and commercial craft he shows approaching his Mediterranean port. Characters on board chat, a sailor gathers in the lowered sail – everyday events. The sun catches the white turban of the sailor and the characteristic shape of the galley’s keel under the transparent water, all under Dutch control.

The man-of-war (or battleship) at anchor in the harbour on the left flies the Dutch flag at the stern. Bakhuizen signed the painting on the white stripe in a flourish of gold paint. Below it, on the stern itself, are the arms of the city of Amsterdam: two golden lions and black St Andrew crosses. Only one sail is furled and the gun ports are open with the canons still protruding, so the great ship has just arrived in port but is still a force to be reckoned with.

It’s hard to tell if the ship on the right is sailing towards or away from us (although this would be backwards). The sails are swung round away from the line of travel and are flapping, a way of moving the ship forward but slowing it down. The bow wave gives us the answer: it is heading towards the harbour.

Bakhuizen often painted ships far out at sea less distinctly, making them hazy to emphasise their distance, and the landscape background is often simply sketched in. But his portrayal of each vessel in the foreground is always meticulous. He always painted real ships alive and responding to a real sea that has depth and power. Here, he shows the rigging (ropes that hoist and control the sails) with great accuracy.

In the bow, a row of sailors stand, arms raised, to tie down a furled sail. Others lean over the side, their backs to us, working in unison: a Dutch ship is a well-run ship, he implies. The men are busy and orderly. Even the little waves in the darkened foreground are in unison. They sweep in rhythm, setting the sense of movement, setting the vessels rolling with them.

Bakhuizen’s paintings are physical. You can almost feel the wind and the spray, hear the slap of the rigging and the flap of the flags.