▁unit ▁training , ▁which ▁last ed ▁until ▁ 1 3 ▁March . ▁Following ▁their ▁return ▁to ▁the ▁North ▁Sea , ▁the ▁ships ▁participated ▁in ▁a ▁series ▁of ▁une vent ful ▁fleet ▁sort ies ▁on ▁ 2 9 – 3 0 ▁March , ▁ 1 7 – 1 8 ▁April , ▁ 2 1 – 2 2 ▁April , ▁ 1 7 – 1 8 ▁May , ▁and ▁ 2 9 – 3 0 ▁May . ▁Ost f ries land ▁and ▁the ▁rest ▁of ▁the ▁fleet ▁remained ▁in ▁port ▁until ▁ 4 ▁August , ▁when ▁I   S quad ron ▁returned ▁to ▁the ▁Balt ic ▁for ▁another ▁round ▁of ▁training ▁man eu vers . ▁That ▁month , ▁K z S ▁Ernst - Old wig ▁von ▁N atz mer ▁replaced ▁Engel hardt ▁as ▁the ▁ship ' s ▁command ing ▁officer . ▁From ▁the ▁Balt ic , ▁the ▁squad ron ▁was ▁attached ▁to ▁the ▁naval ▁force ▁that ▁attempted ▁to ▁swe ep ▁the ▁G ulf ▁of ▁R iga ▁of ▁Russian ▁naval ▁forces ▁in ▁August ▁ 1 9 1 5 . ▁The ▁assault ▁force ▁included ▁the ▁eight ▁I   S quad ron ▁batt les hips , ▁the ▁battle c ru is ers ▁, ▁, ▁and ▁Se yd l itz , ▁several ▁light ▁cru is ers , ▁ 3 2 ▁destroy ers ▁and ▁ 1 3 ▁mines we ep ers . ▁The ▁plan ▁called ▁for ▁channels ▁in ▁Russian ▁mine fields ▁to ▁be ▁swe pt ▁so ▁that ▁the ▁Russian ▁naval ▁presence , ▁which ▁included ▁the ▁pre - d read n