calc general boat cat (#436)

Reviewed-on: Ruderverein-Donau-Linz/rowt#436

src/model/logbook.rs

@@ -126,6 +126,7 @@ pub enum LogbookCreateError {
     NotYourEntry,
     ArrivalSetButNotRemainingTwo,
     OnlyAllowedToEndTripsEndingToday,
+    CantChangeHandoperatableStatusForThisBoat,
 }
 
 impl From<LogbookUpdateError> for LogbookCreateError {
@@ -302,6 +303,12 @@ ORDER BY departure DESC
             return Err(LogbookCreateError::BoatNotFound);
         };
 
+        if log.shipmaster_only_steering != boat.default_shipmaster_only_steering {
+            if !boat.convert_handoperated_possible {
+                return Err(LogbookCreateError::CantChangeHandoperatableStatusForThisBoat);
+            }
+        }
+
         if boat.amount_seats == 1 && log.rowers.is_empty() {
             log.rowers = vec![created_by_user.id];
         }