The Zerstörer 1936 class were slightly bigger and improved to their predecessors, the Zerstörer 1934 and Zerstörer 1934A.
While these ships were under construction, none of the earlier ships was commissioned and therefore none of their design flaws got obvious.
It's interesting that most of the problems - especially those of the engines - were solved in this class of ships. The engines were much more reliable, the structural integrity was improved and they were much better seagoing ships. This was caused by the reduction of the top weight, the funnels were shortened and the height of the superstructure was reduced and the improved bow shape of the three last build ships.
Although 26 of this ships were ordered, only 6 were completed, while the other orders were modified to other designs. All but one ships were sunk at Narvik and formed the destroyer graveyard in the Norwegian fjord.