St Kilda mailboat. A crudely made, boat-shaped block of wood with hollowed out interior, closed by a swing lid. In poker work on the lid 'St Kilda MAIL BOAT LETTERS INSIDE'. The container is attached to a float made from a sheep's bladder. This and similar mailboats were used by the inhabitants of the island of St Kilda to send messages to the Scottish mainland until the population was evacuated in 1930. The mail usually reached the mainland within a day or two but on occasions was picked up in Iceland and even Denmark.