Should fleet tankers use civilian standards?

What are the risks of Germany procuring fleet tankers built to civilian standards?

They may be economical, but existing naval designs are available and the new ships still need suitable defensive features.

Germany's choice of civilian construction is questionable when cost-effective naval auxiliary designs already exist. Domestic construction may explain part of the decision, but ships supporting combat forces still need credible protection and survivability provisions. Fleet oilers operate inside a military logistics system even when their basic cargo resembles commercial shipping. The procurement question is therefore about the standards and defensive fit required for contested support, rather than merely the cheapest hull.