WSV Op 't End is the water sports association of Uithuizen, founded in 1972, with a marina situated at the end of the Boterdiep — a location that inspired the association's name. It is one of the northernmost inland harbours in the province of Groningen.

The marina welcomes both permanent members and visiting boaters.

Arriving guests receive a bag at the last bridge before the harbour containing tourist information and a key to the harbour building, which is equipped with shower, toilet, and washbasin facilities. Water and electricity connections are available at the quay.

The harbourmaster makes a daily round to collect fees and answer questions. The approach to the harbour passes through the picturesque hamlet of Doodstil, voted the most beautiful place name in the Netherlands in 2005.

Nearby attractions include the Menkemaborg estate with its gardens and moats, and shops and restaurants are within walking distance of the harbour.