Archaeologists had 12 days to excavate a 400-year-old wreck before gas-pipeline dredging

The schedule comes to fewer than two dives a day ^[1]. The site lay about 7.5 metres down on a soft, silty seabed, and the slightest movement by a diver clouded the water ^[4]. The team documented each find on deck and put it straight into temporary water storage nearby to prevent further damage ^[5].

Michał Grabowski, an underwater archaeologist at the University of Warsaw, recognised the wreck from the first objects. "When I saw the collection of artifacts in the photograph, it occurred to me that they must have come from a wreck," he said ^[18]. Much of that wreck had not survived ^[6]. The hull is one patch of outer planking about 7.5 metres long, plus loose frames and timbers scattered across the seabed ^[6]. The planks overlap like roof shingles. They were hammered in with iron nails and the gaps sealed with tar and animal hair, a method known as clinker construction ^[7].

The tree-ring window falls 384 to 397 years before the 2023 discovery ^[2]. That window is the basis for calling the ship roughly 400 years old ^[2][8]. A felling date records when the wood was cut ^[8]. The ship was built some time after that and sank later still, and the rings cannot say when.

Alongside the working gear, the team found carpentry tools. One is a hand-drill handle similar to those recovered from the Tudor warship Mary Rose, and the authors take the tools as a sign that the ship carried a workshop for long voyages ^[10]. There were few personal belongings: two shoe soles and a stitched leather strap. Bones show the crew ate pigs and either sheep or goat ^[11]. One object has no known parallel. It is a flat clay brick with a series of holes, lodged in a block of oak, and the report suggests it may have been an improvised aid for sharpening blunt chisels and drill bits ^[12]. "I had no idea what it was, but I really wanted to solve the mystery," Grabowski said. "And I still very much want to." ^[13]

How the ship was lost is even less clear. Some timbers were burnt, perhaps in a fire ^[14]. Two anchors, and a type of buoy used when an anchor was out, suggest the ship was lying at anchor when it went down ^[14]. Grabowski is cautious about reading much into this. "I try not to speculate," he said. "Otherwise, we risk creating an alternative history." ^[15]

Dozens of wrecks have now been found in the bay, as offshore gas, oil and renewable energy projects turn up seabed anomalies that prove to be wrecks ^[17]. According to the phys.org account, many of those were found early enough in project planning for proper excavations ^[17]. This one came up while divers were clearing anomalies, with dredging about to begin ^[1][3]. The account does not say how many of the bay's wrecks were found late. Without that number, one rushed excavation cannot show how much underwater heritage these projects put at risk ^[17].