It would be very useful if the restriction 'can only use waterways' would also allow boats also to use open water fields adjacent to a coast field. This would facilitate interfacing with harbours and allow them to use estuaries.
I know there's a problem with horses walking on the water then.
Or maybe only water of the shallowest depth?
What is an "open water field" here? The way constraints system isn't really set up to interface with open water.
perhaps meaning "a water square bordered on at least one side by land" ...?
In other words, water squares so bordered would be treated as river tiles when checking for "use only waterways"... yes?
In other words, water squares so bordered would be treated as river tiles when checking for "use only waterways"... yes?
Yes, indeed.
Or maybe only water of the shallowest depth?
In most maps i've seen this would be almost equal to no restriction at all.
I don't think that there is an easy way of checking whether a water tile is bounded by land. And wouldn't that make the restrictions of limited effect, as (say) canal barges towed by horses could always skirt the coast from one canal/river to the next?