Why no modern craft exactly reproduces the E-boat

What is the modern equivalent of an E-boat?

There is no exact match. A modern German candidate is far larger, while Iranian fast attack craft approach the role without fully reproducing it.

One modern German candidate is too large at roughly 1,840 tons. Iranian fast attack boats come closer to the small, aggressive coastal role without becoming direct equivalents. Mission resemblance does not erase changes in sensors, weapons, survivability, and displacement. The comparison is therefore cautious rather than a misleading one-for-one lineage.