De Vriendschap (The Friendship) is a seasonal passenger ship that organizes various tours and trips on the Wadden Sea, including day trips to Vlieland.
They also provide the only Robb trips in a special and unique area on the Wadden Sea, the Eijerlandse Gat. In this quiet area, many seals lie on the sandbanks, nowhere on Texel you can see as many as there!