▁mist ress ▁Hed wig ▁Pot th ast . ▁ ▁The ▁lake ▁is ▁noted ▁for ▁its ▁clear ▁water ▁and ▁is ▁advert ised ▁as ▁the ▁clean est ▁lake ▁in ▁Germany . ▁For ▁this ▁reason , ▁only ▁electric - power ed ▁passenger ▁ships , ▁row ing , ▁and ▁ped al ▁boats ▁have ▁been ▁permitted ▁on ▁the ▁lake ▁since ▁ 1 9 0 9 . ▁Pass enger ▁services ▁along ▁the ▁length ▁of ▁the ▁lake ▁are ▁operated ▁by ▁the ▁Bayer ische ▁Se ensch if ff ah rt ▁company ▁and ▁call ▁at ▁Se el ände ▁( Sch ön au ), ▁St . ▁Bar th ol om ä , ▁S alet ▁( mid - A pril ▁to ▁mid - Oct ober ), ▁and ▁K essel ▁( on ▁request ). ▁In ▁ideal ▁conditions , ▁the ▁longest ▁tour ▁takes ▁two ▁hours ▁from ▁Se el ände ▁to ▁S alet . ▁Sw imming ▁is ▁permitted ▁except ▁in ▁the ▁lock ▁area ▁at ▁Se el ände . ▁ ▁Due ▁to ▁its ▁pictures que ▁setting , ▁the ▁lake ▁and ▁surrounding ▁park lands ▁are ▁very ▁popular ▁with ▁tour ists ▁and ▁h ik ers . ▁In ▁addition , ▁the ▁surrounding ▁she er ▁rock ▁walls ▁create ▁an ▁echo ▁known ▁for ▁its ▁clar ity . ▁On ▁boat ▁t ours , ▁it ▁has ▁become ▁traditional ▁to ▁stop ▁and ▁play ▁a ▁fl ugel horn ▁or ▁tr ump et ▁to ▁demonstrate ▁the ▁echo . ▁Pre viously ▁demonstrated ▁by ▁shooting ▁a ▁can non , ▁the ▁echo ▁can ▁be ▁heard ▁to ▁rever ber ate ▁up ▁to ▁seven ▁times . ▁The ▁tr ump eter ▁plays ▁along ▁with