When the guest harbour of Nagu was being developed, the concept of an illuminated sea channel between Kyrkbacken in Nagu and the island of Själö was considered. Thanks to the hard work of Chief Pilot Osmo Myllymaa, the project was implemented and several new beacons were erected in a 4.3-metre deep channel between the islands of Kuddarholmarna, Utterberg, Taslot and Svingrundet. One more beacon was needed to indicate the entrance to the harbour of Nagu. A beacon was erected at the tip of the island of Ernholm, close to the mouth of the entrance to the harbour. The beacon was a replica of the Sander lighthouse at the northern tip of Enskär at the entrance to the harbour of Utö.