A tour in a rubber dinghy is one of the most relaxed afternoon activities for a stag or hen party in Cologne. You can paddle comfortably past the old town and Cologne Cathedral up to the Rheinpark. You make a stop at the Hohenzollern bridge to fasten a lock to it according to old custom and sink the key into the Rhine river.
At the well-known boat restaurant "Alte Liebe" you can enjoy a round of Kölsch and after the tour you can even book a barbecue for a small extra charge. Bachelor heart, what more do you want?