I know it’s a bad idea, but what do you think of Watergate?

Cost: 40 wood 15 stone

Can be placed over two tiles of water. Building requires at least one villager on either side to construct. Can be locked/unlocked. Can not be converted by enemy monks.

Stats: 500HP, Pierce Armour 3, LOS 5, Build time 45sec

I can see how problematic this might be so if this idea has been talked about before I would love to hear about it