[3] Around 1904 John Isaac Thornycroft set up the Hampton Launch Works on the island, an offshoot of the Chiswick boatyard that he had established in the 1860s.

This boatbuilding works concentrated on cabin cruisers and speedboats, but the success of Thornycroft's operations on Platt's Eyot led to the award of contracts from the Admiralty.

During the First World War, in 1916 the Admiralty commissioned a new type of fast torpedo-carrying motor launch which Thornycroft constructed secretly in its Platt's Eyot facility.

Four new boat sheds were constructed on the island, probably in the same year (though the date is disputed by some), to a design by Augustine Alban Hamilton Scott.

They were built using the Belfast truss system, developed during the First World War to roof wide structures such as aircraft hangars.