prize8-4, Exercise 2: The Bell Rock and the Eddystone

Model answer (check the details):

Shared problems: both towers stood on rocks far from the shore that the sea covered at high tide; work could be done only for short periods at low water and in calm weather; the blocks had to be cut on shore and brought out by boat; both required a tower that could survive storms; and both used interlocking granite blocks to make the tower a single mass.

How the Bell Rock differed:
- It lay completely under water at high tide and only a few hours of work were possible each day, whereas the Eddystone stood slightly higher and more of it remained dry (check).
- The Bell Rock builders used a wooden barrack on iron legs standing on the rock itself, in the second year, so that the men could stay close to the work during the summer.
- It benefited from Smeaton's published account, which Stevenson used as a guide.
- It was built with light that alternated red and white, a feature of its own.
- The east coast of Scotland has its own weather, and supply came from Arbroath.

Conclusion: the Bell Rock was a repeat of the Eddystone method in a harsher working environment, and its success owed much to the earlier example.

Care: confirm tide times, heights and dates in the engineers' own accounts.