loď can be any ship or boat of any size (a huge tanker, a single kayak,...)
člun is a boat (roughly)
loďka is a small boat, most likely human powered or with only a small motor (not used too much for kayaks and canoes)
lodička is probably just a toy ship or a type of a cap or a court shoe
Thanks for the oversight. But given your descriptions and the online dictionary I consulted for a confirmation on the translation of “člun” as a boat (German: Boot, Kahn; the latter which can be translated as a trawler, a commercial fishing boat), could I say that both are human-powered, could thus describe a rowboat? Or would “člun” be a motorised boat, whereas the “loďka” is a rowboat?
Thanks in advance!
It is broader, I tried to write it in the best way I could in my previous comment.
Člun can be motorized (motorový člun), or it can be a rowboat. It can be a larger military vessel (dělový člun - gunboat). It can be a safety boat stored on a large ship (záchranný člun). Less commonly, člun can also have sails (e.g., rybářský člun - fishing boat). Usually it is not covered.
Loďka is used much less often and if you search it in the google image search you will see what kind of boats they are.