Once the boat has navigated the helix, it makes a left turn before dropping a final time.
It is a small, winding river, tidal over its lower reaches, which large boats could not navigate.
He knew a boat couldn't navigate through the ice, and he wasn't sure a helicopter could make it through the storm.
Today the cove is so silted, a boat could not navigate there.
Visitors can rent boats to navigate the island's several ponds and canals.
The reeds made the marsh very difficult for enemies to travel through; only small boats that were driven by poles could navigate the area.
"Our Christmas market tours will not be affected because if boats cannot navigate the river then we will take people by coach," said a spokesman.
Few boats can navigate on the boulder flats where the carp like to spawn and feed.
The boat navigated inland another mile and a half.
Draft determines the minimum depth of water a ship or boat can safely navigate.