(h) Cimrman konstruoval zvláštní vzducholoď. Za tuto vzducholoď mu poděkoval Zeppelin

First step: identify the common entity: vzducholoď.

Second step: který must take the gender and number of vzducholoď: fem. sg. (loď is a feminine noun like píseň)

Third step: který must take the case from the second clause: acc. (in the prepositional phrase with "za" in the sense of "in exchange for")

Fourth step: Be sure to start the který-clause with the preposition za; do not leave it behind somewhere. The preposition must precede the který form because který belongs to the prepositional phrase.