Seems like there is nothing preventing one from building a bridge across the ocean.
This seems to apply to bridges which have no limit to their span such as
Masonry viaduct and
Brick arch viaduct. As long as there are no major obstructions between, eg an island, then nothing stops one from bridging across the deep water of the oceans. It is clearly not intended that companies can build such multi hundred kilometer bridges, especially in the 1830s.
Now the problem is that one is meant to be able to bridge over deep water, after all nothing stops a hanging bridge from doing so as it does not even touch the water. However bridges that require regular supports do touch the water and technically run down to the bottom of the ocean.
My suggestion is the following.
- Bridges with a finite span, suggesting hanging/suspended design, ignore water height. As long as their span is respected they will bridge across everything.
- Bridges with an infinite span, suggesting periodic supports, are restricted to the same deep water height restrictions as elevated ways.
- Feature Extension: Bridge types can define a maximum pillar height. When bridging over water this height is measured from the ground beneath the water. This would allow hanging/suspended bridges to have infinite pillar height while elevated infinite span bridges can only be built a maximum height above the surroundings including deep water. Maybe a separate field for in water compared with out.
In the mean time I would suggest making a make shift rule preventing people from building such bridges on the server game. It would entirely defeat the point of ships when one could replace everything with across the ocean rail transport. Ships would not be able to compete at all since they move considerably slower than trains.
Thank you for the report. The (basic version of) the feature that you suggest had been coded some years ago, but, having checked, it appears that this was removed when another contributor added a different feature in 2014. I have now restored this feature and this should be available in to-morrow's nightly build.