Some boats : US zodiac but also all rubber boats, rescue/assault boats (rubber boat) can't move on river Vltava (Gabreta) (all vanilla + CSLA rubber boats), at any place on river. Neither water scooter (vanilla).
The engine is on, the propeller turns but no speed, no move.
Curiously, RHIB, amphibious APC, motorboat, speedboat minigun are ok at same places. Not a problem of room. Your can test in large area of Vltava, SE of the map.