A recent consultation document from the RYA draws attention to the possibility that renewable energy facilities at sea may give rise to two unexpected dangers. The presence of large quantities of steel, cabling and electricity may cause local magnetic anomalies that can upset a compass severely. There is also a concern that interference from such developments will cause radar users to turn down their gain control to clean up the picture. They’ll still be able to see the supertankers, but the likes of us may disappear altogether. Forewarned is forearmed!