Baltic submarine design had several national lineages

What should we make of prototype submarines associated with German designers, Finland, and the Netherlands after World War I?

German specialists contributed, but Finnish and Dutch naval architects had their own ideas and sometimes led in technologies they chose to develop and fund.

German submarine specialists offered consultations after World War I, while Finland and the Netherlands maintained strong naval architecture of their own. They assessed those proposals and developed their own ideas. Dutch, Finnish, and other Baltic work sometimes advanced beyond German work in particular technologies where local designers and funding concentrated. German involvement therefore does not establish sole authorship of these designs.