Raising a canal's water level using anchored tug boats? You've all read about the enormous container ship stuck in the Suez Canal:
 source
They're planning to attempt to unstick it today when the tide is high, as the 50cm rise in the water level should help significantly.
That, plus all the tugboats running around the scene of the stranding, led me to wonder if anchored tugboats could be used to significantly raise the water level in the canal. If you anchor two tugboats in a canal, facing away from each other and pulling as hard as they can against their rodes, it should raise the water level in between them. But by how much?
Assumptions:

*

*We are in the Suez Canal, which is 313m wide at the surface, 121m wide at the bottom, and 24m deep


*Typical tugboats have a bollard pull capacity of about 450 kilonewtons


*The tugboats are far enough apart that we don't have to worry about local flow effects


*The water level on either side of the pair of tugs is constant
 A: If there was only one tugboat, then the effect would be to pump water along the canal. But the opposing tug prevents that; the force of the pushed water from one balances against the push of the water from the other.
Since the tugs are isolated, we can treat the push of each tug as a generalized push against the water. Model this as a surface spanning the canal and pushing against the water with the force of the tug. The pressure applied to the surface will be balanced by the higher water level on the pushed side.
The cross-section of the canal is 5200 square meters, so a 450 kn-capacity tug would be equivalent to a pressure across the surface of 87 newtons per square meter. This is balanced by the additional weight of the higher water level on the other side of the surface. 87 newtons is the force applied by 8.8 kg of water, so there's an additional 8.8kg of water on top of each square meter of surface, which corresponds to 0.88cm of water. So, the pair of tugs would raise the water between them by 0.88cm.
To achieve the 50cm rise that is expected to come from the high tide, we'd need 114 typical tug boats, 57 on either side, steaming away. The world's strongest tug has a bollard pull of 4,680 kN, so we'd only need 12 of them, six on either side. Easy peasy.
