The ninth album from German instrumental experimentalists Anchor and Burden, Sunken Fleet backs off from the anger and aggression of Extinction Level and its adjunct mini-album Afterglow. But that doesn’t mean that the quartet has gone soft. As might be implied by the title, Sunken Fleet is an album about the ocean, a natural phenomenon that evokes both wonder and terror. Opener “Sunken Caravan” gives the first clue that this won’t be a smooth ride – the murky tapestry of keyboardist Bernard Wöstheinirich’s mysterious synth colors, Asaf Sirkis’ wandering polyrhythms, and touch guitarists Markus Reuter and Alexander Paul Dowerk’s discordant riffing could accompany an underwater camera exploring the beauty of the deep if not for the foreboding atmosphere. The way the steady grunge weighs down the busy drumming and tinkling electronics in “Pendulum” and “Abandoned Vessel” brings to mind hurricanes on the surface of the otherwise placid depths. As gorgeous as the water and the life within it can be, the danger inherent in the depths is never far away. There’s wreckage, possibly even skeletons, down there amongst the coral and sea anemones, and Anchor and Burden never lets you forget it.