Passage: Derfflinger also took part in the bombardment of Yarmouth and Lowestoft on 24–25 April 1916. Hipper was away on sick leave, so the German ships were under the command of Konteradmiral Friedrich Boedicker. Derfflinger, her newly commissioned sister ship Lützow, and the veterans Moltke, Seydlitz and Von der Tann left the Jade Estuary at 10:55 on 24 April. They were supported by a screening force of 6 light cruisers and two torpedo boat flotillas. The heavy units of the High Seas Fleet, under the command of Admiral Reinhard Scheer, sailed at 13:40, with the objective to provide distant support for Boedicker's ships. The British Admiralty was made aware of the German sortie through the interception of German wireless signals, and deployed the Grand Fleet at 15:50.By 14:00, Boedicker's ships had reached a position off Norderney, at which point he turned his ships northward to avoid the Dutch observers on the island of Terschelling. At 15:38, Seydlitz struck a naval mine, which tore a 50-foot (15 m) hole in her hull, just abaft of the starboard broadside torpedo tube, allowing 1,400 short tons (1,250 long tons) of water to enter the ship. Seydlitz turned back, with the screen of light cruisers, at a speed of 15 knots (28 km/h; 17 mph). The four remaining battlecruisers turned south immediately in the direction of Norderney to avoid further mine damage. By 16:00, Seydlitz was clear of imminent danger, so the ship stopped to allow Boedicker to disembark. The torpedo boat V28 brought Boedicker to Lützow.At 04:50 on 25 April, the German battlecruisers were approaching Lowestoft when the light cruisers Rostock and Elbing, which had been covering the southern flank, spotted the light cruisers and destroyers of Commodore Tyrwhitt's Harwich Force. Boedicker refused to be distracted by the British ships, and instead trained his ships' guns on Lowestoft. At a range of approximately 14,000 yd (13,000 m), the German battlecruisers destroyed two 6 in (15 cm) shore batteries and inflicted other damage to the town, including the...

Question: A V28 is what kind of boat?
torpedo boat