How (or where) would large, medieval or even ancient/roman ships have been assembled? I'm asking of ships the size of dutch galleons and of the 13/1400's possibly
Did they have the concept of dry docks? Were they assembled on ship cradles? or simply on land, propped up?
If they were assembled on land was it in the open or sheltered and how would they roll it into the sea? Would this have been at an open point on the coast, or inside a harbour/dock?
When searching how ships were built, you can find lots of information about techniques like wood bending, but not where it was all put together
Dutch galleon's aren't really medieval/ancient but 17th century, but I am glad you mentioned them as there as there is this wonderful contemporary collection of artwork showing the entire process of building a 17th century Dutch ship. Now, in general the process actually wasn't that much different in medieval ages then in 17th century, although plenty changed in terms of design of ships and techniques. A lot of the actual process of the way the ship was built, and that varied a lot on time and locations. E.g. if the ship was shell-first, or skeleton-first built. How the planks would be joined, and the general shape. Lot of it influenced the shipbuilding technique. Although the shipyard would look mostly the same.
Did they have the concept of dry docks? Were they assembled on ship cradles? or simply on land, propped up? If they were assembled on land was it in the open or sheltered and how would they roll it into the sea? Would this have been at an open point on the coast, or inside a harbour/dock?
You can probably find examples of each of these lists of ways to build ships. Likely the most common was the simplest: on land/beach right next to water, propped up with supporting beams. At certain stage the not-yet-finished ship would be put into the sea and then completed. Masts would bu places, final construction of upperworks would be done. Yards, rigging and sails would be hoisted and finally all the miscellaneous items and supplies and would be brought on.
Most of these shipyards right in the open but occasionally designated galley shipyards were roofed (as the galleys were low enough for it to be possible) as we can see in these images of Venetian arsenal and you will find similar structures for galley docks across the Mediterranean.
To help visualize I've collected various images of mostly Renaissance and Early Modern era harbors and ports. Plenty have some sort of shipyard facility included. Here are the collections:
