Early September 2011 two 40-ton Landy Archimedes hydropower screw turbines were transported from Sneek, The Netherlands to the royal Windsor Castle, UK. Both screws are installed at Romney weir on the River Thames and power both the Royal Castle as well as 400 – 500 local households. The Landy screws dimension 4 meter diameter, 6 meter long and capacity 150 kW. Unique feature of each screw is the number of flights; here being 5 instead of usually 2 or 3. As the screws are of fishfriendly design, fish migration upstream and downstream is still possible.