Factorio Forums

Have you thought about adding a way to expand or explore the sea. There could oil in the water which you could pump and make oilrigs and build into sea.
To make it more balanced there could be aliens that live on water to bully the player and harass. Boats or/bridges could be a nice addon too for crossing water somehow!

It is an intersting idea. Did you search for this topic (sea, boats, bridges)? Often ideas have already been posted or similar ideas exist. The moderator ssilk compiles many ideas into groups with short descriptions. Boats have definitely been discussed before. Bridges maybe, too.

Right now, I think (don't know, haven't been to any internal meetings) that the devs deliberate do not add water stuff to the game because there are so many other areas more pressing to improve and develop right now. If you go through the posts on this topic and have ideas that have not yet been posted, then it is a good idea to develop them in your head a bit and post them here.

What problem is in the game right now? (E.g. can't cross oceans, not enough oil.)

How does your idea solve it? (E.g. boats, more oil wells in the ocean, how would the oil wells work in detail, how would they be built?)

How does your idea differ from existing solutions or already posted ideas? (e.g. boats have been posted, but maybe no oil platforms)

Why is your idea better than alternative solutions?

See also
viewtopic.php?f=80&t=14024 Travel over Water: Boats, Ships, Canus / Bridges / Tunnels
viewtopic.php?f=80&t=262 Water as limited ressource

The subjects about "water" are very wide, from fishery to salt water processing. From new types of natives to tsunamis.