The Veluwemeer Aqueduct, also known as the Drontermeeraqueduct, is a unique structure in the Netherlands that carries a canal over a large lake.This impressive water bridge spans the Veluwemeer lake, connecting the provinces of Flevoland and Gelderland
Tall sail boats.
But it’s only 3m deep. How long are keels on tall sailboats?
A lot of the sail ships used on inland waters here have flat bottoms, like for instance the skûtsje. So they can sail in quite shallow waters.
[edit] I’ve looked it up and for instance a tjalk (historic freight ship) can have a mast height of around 20-25 meters, but has a sailing depth of only 80-200 cm. Due to their flat bottoms, they can easily move around the inland lakes and canals, which are often only a few meters deep.