Wilhelm Krag Wreck

Descend onto sand around 28 metres off Lagos, onto a hull that has spent more than a century breaking apart underwater. The superstructure is gone; what remains are the boilers, the bow and the stern, spaced along the wreck like stations on a route rather than one continuous structure. The wreck's depth shifts depending on who is reporting it: the operator running regular trips here logs an average of 28 metres with a 34-metre maximum, a travel writer clocks the accessible section at 29 metres and the deepest point at 36, and the site's own database entry rounds it to a flat 30. None of those numbers lines up with another, so treat the shallow end as the plan and anything past 30 metres as the day's bonus depth. Large seabream and wrasse move over the plates, and conger eels and moray eels hold inside the collapsed boilers themselves, close enough that a slow pass finds several without searching. Octopus and spider crabs work the same crevices. Portugal Dive, which runs both recreational and technical trips to the wreck, calls it one of the biggest in the area.

Wilhelm Krag Wreck is the only wreck in the Lagos-Portimao sector: the Algarve's other named wrecks, including the purpose-built four-ship park at Ocean Revival, sit well to the east near Portimao and Faro. Reaching it means a straightforward boat run from Lagos itself, not the longer trip out to Portimao. On 24 April 1917 the German submarine U-35, commanded by Lothar von Arnauld de la Perière, credited with the largest tonnage sunk by any submarine commander of the war, shelled and sank four Allied ships off the western Algarve in a single day: this steamer, the Norwegian SS Torvore, the Danish SS Nordsoen, and the Italian sailing ship Bienaime Prof. Luigi. That attack, later the subject of a dedicated naval-archaeology survey, is what draws divers to this particular wreck rather than the area's other sites.

Built in 1899 on the Tyne as the steamer Nordpol, she changed names five times over two decades under Norwegian and Danish ownership before her final registration in December 1916 as Vilhelm Krag, owned by D/S A/S Vilhelm Krag of Bergen.1 Four months later, on 24 April 1917, U-35 captured and shelled her roughly five nautical miles west-by-south of the Ponta da Piedade lighthouse near Lagos, while she sailed in ballast from Genoa to Barry.1 The Portuguese Navy's only local defence, the steam tug Galgo, was in Lagos harbour when the attack began and could not intervene in time;2 it later rescued the surviving crew and brought them into Lagos port.

A century after the sinking, a joint team from the Naval Research Center and the Naval School, led by commander Augusto Salgado and historian Jorge Russo, surveyed the cluster of ships lost that day between 2014 and 2017. The project won the Nautical Archaeology Society's Adopt a Wreck Award in 2015, and the centenary was marked with a commemorative dive and a plaque at Sagres in April 2017.2

Working the lower sections of this wreck means diving past 30 metres, at or beyond recreational no-decompression territory, so a deep specialty or equivalent belongs on the checklist alongside a properly planned gas supply. Loose fishing net reportedly clings to parts of the debris; carry a cutting tool and give net-draped structure a wide berth. Access is boat-only from Lagos port. Bring a 7mm wetsuit in summer and a drysuit or semi-drysuit in winter, the standard the area's wreck sites call for. June to October is named as the calmer, warmer window to dive it. No marine reserve, permit or diver quota applies to this wreck specifically.