OSBM Bolt: Whirly   

NEW OSBM BOLT ROCK 13.0M NE SIDE RD 24.3M NW C CATTLE GRID (5.803m above Lerwick datum, 2nd order, new 1978).

Location
Grid reference: HU 4925 8051.
Landranger 1: Shetland, Yell, Unst & Fetlar.
Landranger 2: Shetland, Sullom Voe & Whalsay.
Landranger 3: Shetland, North Mainland.
Structure: Rock outcrop.
Waypoint: OS2620.
The nearest fundamental bench mark is Duncansby Head, 237.17km to the southwest.