Pedalos can be hired by the hour, but you should always allow yourself plenty of time to return to shore before your rental period has expired.
It takes a long time to get back to shore by pedalo. 
mnli hypothesis: It takes a long time to get back to shore by pedalo.  premise: Pedalos can be hired by the hour, but you should always allow yourself plenty of time to return to shore before your rental period has expired.