What are some mechanical ways to help propel a ship through a canal?
there is as a system of canals that connects a country, these canals are about 10 meters wide 15 meters deep, i am designing a ship that was built specifically to travel the canals, its main purpose is maximum weight while maintaining a speed of 8 miles per hour or about 7 knots. the ship size should be enough for heavy transport so no small boats.
the question is what are some ways that I can achieve a 7 knots speed?, some points to consider:
1. the material that the ship is made of is wood and whatever metals used in building a ship, keep in mind that i can invent wood with some different properties if that would help.
2. the ship transports people or animals or sometimes just cargo.
3. winds cant be considered because these ships need to move when needed and people can't just wait for the winds.
4. there isn't a significant current or stream to use for the ship movement.
5. 308
there are a series of outposts all along the canals something like every 5 miles, i made these to serve as posts where Profesional rowers await in case if an urgent message needed to be delivered so that they can keep a fresh crew. these outposts can be developed further if needed to accommodate the cargo ships.
6. there exist animals that naturally dig canals that were domesticated and then used to dig the canals.
i know an obvious answer would be an engine of some sort but that would results in my world industrialization ( i need it to remain medieval-like). rowing teams are also not ideal, some idea that I had were to use animals on both banks of the canal to pull the ship and replenish them at the outposts. that would work but i am looking for more of a mechanical solution.
i thought of using a rope that can be reeled at each outpost but I can't just have a five-mile rope. i thought about using some form of stored power ( other than a steam engine) something like compressed gas that can be used to move the ship but, i doubt there was technology in medieval time that could compress large amounts of gas.
now a steam engine would work but i would need a reason that those people don't just look at it and think of using it to build trains and cars ( ruining the time period I'm looking for) 658