Visitors to the Vikingship Museum in Oslo, Norway, wonder why there is a notch extending from the holes that were used as oarlocks on Viking longboats. The notch allowed the blade of the oar to pass through the hull from inside the boat. If the Vikings had not cut the notch, they would have had to reach overboard with a long and heavy oar and struggle to pass the handle through the oarlock while leaning over the gunwale — not an easy task even in calm seas. With the notch they could slip the oars in and out without the risk of losing the oars — or themselves — overboard.