Lighthouse-keeper stays, since the lighthouses are there and empty

A first step

Find out which body manages the lighthouse you have in mind by writing to the district office, and ask on what terms a building could be leased for guest stays. While you wait, post a mock listing for a lighthouse-keeper's night with a price in a travel group abroad and count the enquiries. A written answer on lease terms and a list of people asking to book are the two pieces of proof.

Who pays first

A couple from Europe or the Gulf looking for one unusual night to anchor a coastal trip, who will pay above a hotel rate.

What leaves today

The lighthouses stand empty and earn nothing, while unusual heritage stays sell at high nightly prices on other coasts.

The idea and the mechanism are from the book. The first step was written for this site as a suggestion; if you know a better one, say so.

The test

Does it keep value that now leaves the island, or build the proof that lets somebody else do so?

The only test any idea on this site has to pass. The four rules that go with it are here.

In the book

• Ch. TwoAn Island Nobody Has Counted
  An ocean eight times the size of the land

More from cluster 13

• 251Sailing charters and a yacht marina at Galle or Trincomalee, with the crew trained here
• 252Diving schools at the wrecks of Trincomalee and the reefs of the east, certified to international standard
• 253Sport fishing charters with catch-and-release, sold to the Gulf and Europe
• 254Sea-cucumber and seaweed farming in the northern lagoons, which Japan and Korea buy
• 255Tuna graded, loined and vacuum-packed at the harbour for the sashimi market, not sold whole
• 256Crab and prawn from the lagoons as a branded chilled export, with the lagoon's name

All 20 ideas in this cluster