Out recently is Roy Manstan's new book, The Listeners: U-boat Hunters During the Great War, covering the early history of submarine detection devices. If you have been following The Subchaser Archives Notes (or if you have seen my book on chasers), you know that the fleet of 110' submarine chasers used early listening devices to detect and hunt U-boats. Manstan's book covers the bigger picture of the science of listening: design, development, and testing of various different types of devices. 

I found the section on listening devices installed on aircraft to be particularly interesting, given both the similarities and the differences in the challenges, compared to listening on a subchaser. Sea planes were used to spot submerged submarines from the air, but as Manstan explains, they could also land on the surface, extend listening devices into the water, and serve a similar role to a subchaser, reporting the direction of a detected submarine relative to the sea plane's position.

Also covered are related tools used in tracking submarines, such as the Position Plotter used on subchasers, a device that allowed the unit leader quickly to calculate a rough bearing of a detected submarine by triangulating the bearing reports from each boat in a three-chaser unit.

Part of the scientific work was performed at a Submarine Signal Company facility on Nahant (Boston), but also at other locations including New London, where subchaser crews trained in the new science of ASW. 

Manstan covers a wide range of listening devices and tests, with excellent illustrations, including many photos of the devices. The Listeners: U-boat Hunters During the Great War, is available on the Wesleyan University Press website or on Amazon.

--Todd Woofenden, editor

Recently added to the Hull Numbers Collection:

SC 188, which was stationed at Norfolk, and served in the USS Patterson Group.