[Note 1] UB-16 spent her entire career in the Flanders Flotilla and sank 24 merchant ships, about half of them British fishing vessels.

[4][Note 2] UB-16 and sister boat UB-17 comprised an order of two submarines placed on 25 November from AG Weser of Bremen, a little more than three months after planning for the class began.

[8][Note 3] On 1 June, UB-16 joined the Flanders Flotilla (German: U-boote des Marinekorps U-Flotille Flandern),[1] which had been organized on 29 March.

During this campaign, enemy vessels in the German-defined war zone (German: Kriegsgebiet), which encompassed all waters around the United Kingdom, were to be sunk.

[13] On 12 June, UB-16 torpedoed and sank the 3,027 GRT British cargo ship Leuctra 1.5 nautical miles (2.8 km; 1.7 mi) from the Shipwash Lightship.

On the 27th, Westward Ho!, a 47 GRT smack was boarded and sunk by UB-16's crew 25 nautical miles (46 km; 29 mi) southeast of Lowestoft.

[13][19] The following day, the 1,821 GRT Mangara was torpedoed without warning one-quarter nautical mile (500 m) from the Sizewell Buoy at Aldeburgh.

Holtzendorff's directive from ordered all U-boats out of the English Channel and the South-Western Approaches and required that all submarine activity in the North Sea be conducted strictly along prize regulations.

[27] UB-16's first successes in the new offensive came on 6 March when she sank the smacks Springflower and Young Harry about 30 nautical miles (56 km; 35 mi) east of Lowestoft.

[33] Robert Adamson was sunk 3 nautical miles (5.6 km; 3.5 mi) from the Shipwash Lightship while en route from Dundee to Le Havre with a cargo of props.

[32] Tregantle had sailed from Galveston, Texas, via Norfolk, Virginia, with a load of wheat for Hull, but was sunk off Lowestoft.

[35] In support of the operation, UB-16 and five other Flanders boats set out at midnight 30/31 May to form a line 18 nautical miles (33 km; 21 mi) east of Lowestoft.

[36][Note 6] This group was to intercept and attack the British light forces from Harwich, should they sortie north to join the battle.

[37] UB-16's activities over the next two months are not reported, but on 2 August the submarine was patrolling off the Mass Lightship and torpedoed the Norwegian steamer John Wilson, sending her cargo of food destined for London to the bottom.

The German fleet planned to depart late in the day on 18 August and shell military targets the next morning.

Although U-boats to the north sank two British light cruisers,[Note 8] UB-16 and her group played no part in the action.

[40] Later, on 24 August, UB-16 was again patrolling off the Mass Lightship when Hundius stopped Velox, another Norwegian steamer headed for London.

[46] With the blockade having such dire consequences, Kaiser Wilhelm II personally approved a resumption of unrestricted submarine warfare to begin on 1 February 1917 to help force the British to make peace.

[10] The 107 GRT Dutch motor vessel Arie was sunk in the Hoofden area on 20 April; there were no reports of casualties.

[52] [Note 9] On 9 August, UB-16 torpedoed and sank the British destroyer HMS Recruit 3 nautical miles (5.6 km; 3.5 mi) from the North Hinder Lightship.

In the raid, the British succeeded in sinking two obsolete cruisers, Iphigenia and Intrepid, in the narrowest part of the canal.

[60] British admiral Roger Keyes, who had planned the raid, believed that the Flanders Flotilla ships were bottled up for a long period of time.

Although E34's commanding officer Lieutenant Pulleyne initially believed that UB-16 was a British submarine, he submerged out of caution because of UB-16's proximity to Harwich.

Von der Lühe was imprisoned in a British prisoner of war camp, where he died of influenza on 1 March 1919.

[64] British divers dispatched to the site of UB-16's demise a week later could only find some plating and a few pipes and concluded that UB-16 had disintegrated after the torpedo hit.