The Signal Tower was completed in 1813, three years after the Bell Rock Lighthouse itself, as the lighthouse's shore station. Identical signalling apparatus was installed on top of both buildings: a vertical pole, a heavy black ball that ran up and down it on a rope, and a fixed routine for raising it. In foggy weather, when nothing could be seen at 9 a.m., the watch was postponed to 1 p.m. in the hope that conditions might clear. The Signal Tower also housed the families of the keepers who served their long shifts on the rock. While their husbands or fathers were off at sea, the wives and children lived here on the harbour, watching the same horizon. At night any flicker in the lighthouse beam would send the tender out before dawn.

Arbroath fishing vessels, returning to harbour, would routinely carry small comforts out to the rock. Newspapers. Fresh bread rolls. Tobacco. A letter from home. They would relay messages back to the shore station too, either officially for the Master of the Tender or unofficially as favours to friends. In an age before radio, this informal communication mattered. The keepers depended on it for sanity as much as for supplies. The system held until 1955, when helicopters and faster boats made it obsolete. Staffing was transferred to Leith, home of the Northern Lighthouse Board. The tower's job, after 142 years of silent dialogue with a light eleven miles away, was finally over.

What do you do with a stone building you no longer need? Arbroath Town Council took it over and, for about fifteen unlikely years, used it as council housing. People lived in the keepers' old quarters, raised children where the master of the tender had once kept his telescope, hung washing where signals had been hoisted. In the 1970s the building was converted into a museum. The transformation revealed the depth of stories Arbroath had to tell. The town had once been a major jute processor, home to Shanks Lawnmowers, Giddings + Lewis-Fraser, and Keith & Blackman, all world-known firms. The museum kept the records and the machinery.

Today the Signal Tower Museum houses an unlikely combination of subjects: Bell Rock Lighthouse exhibits and a scale model of the Inchcape Rock alongside vintage Shanks lawnmowers and fishing gear. One of the original light mechanisms from the lighthouse is on display - the brass and glass apparatus that turned night into a warning across the North Sea. Scale models of fishing vessels from Arbroath's harbour show the ships that once carried bread rolls out to the rock. The museum is run by ANGUSalive, the local culture trust. It is small. It is free. It is the kind of place where you can spend an hour and come out understanding more about a particular eleven-mile stretch of water than you ever expected to.