So, in the Ghosts of Saltmarsh adventure book, it gives more in depth information on sea adventuring and ship information. I am running a campaign and my players are located on a large salt water lake (think Lake Erie/Ontario size) that is attached to the sea through an inlet that allows larger sea vessels access to the lake.
They have just recently got access to a folding boat. My question is whether the folding boat can really be thought of as a seaworthy vessel. It folds out to a 24 ft. long boat with a single sail and 5 rows of oars. In the Ghosts of Saltmarsh supplement, the smallest "sailing ship" they note is the Keelboat, which is more than twice the size of the folding boat's largest size (60ft vs 24 ft).
This makes me think that the folding boat would not be seaworthy. And possibly not even good to take too far from shore on the lake if the weather is particularly bad.
As the DM, should I rule that the folding boat will be fine for travel on the lake but that, if they want to go out to sea, they should either charter or even purchase a larger vessel?