Making a ship that works on land forces you to take the worst of both worlds.
Ships are designed/built to withstand different stresses than land vehicles. They also steer/work differently than land vehicles.
Trying to combine both traits together into a single vehicle is something that we can't/won't do even with modern technology. Therefore, less advanced technology isn't going to solve this problem
As brought up before, in order to steer, a ship needs resistance. Ships heel - they tip - as part of their normal steerage. In order to replicate this, you'd need an entire suspension system built - which would be heavy, ruin the sailing profile of the ship unless it's completely retractable, be well beyond the capabilities of the time period to produce, and be very easy to break even if you got it running.
Therefore, we need magic.
The core problem is that ships travel on water, and land is not water - so let's make the land act like water.
Your ship has a good working relationship with the
Your ship has a keel lined in lead, and a series of pipes/masts projecting forward from the hull. There are a number of simple pumps that push small amounts of liquid out of a series of tiny little holes at the front of these pipes. This does make your ship a little less agile in the water than it would otherwise be, but when you approach land, your crew starts in on the pumps, pushing a mixture of air and....
Yes, the universal solvent! Generally thought to be useful only to clean out those really stubborn stains, you've figured out a second use for it.
Projected with sufficient force, with a mixture of air, you create what is in effect a cavitation effect in soil
Which with the proper mix allows your ship to simply plow through soil as if it were water. Your turning radius isn't great, and if the pumps ever all fail you have some problems, and you want a relatively flat surface. But hey, you can sail on land!