Damn I wanted surfing mech pirate battles.

As one who has taken an interest in this, but probably won't be able to join due to other commitments, I would like to present some elements that might be worth thinking about. These are my opinions after looking at the visual reference gallery and reading the posts of others in this thread. I hope that they help with further fleshing out a world that all involved can enjoy.

Cloth as we know it would be almost impossible to acquire without farmland to grow plants for fiber, rope also would be very difficult to make. Hides of various larger aquatic mammals and fish would be far more available and durable for clothing. It is also possible to braid strips of leather into cords of a sort, though their uses would be more limited than twine or rope.

Metals would only rarely be used for weapons as they would be needed for ship repairs and such, provided that the ships in use are metal or use metal components. It would also be a very valuable trade good, comparable to gold.

For those settlements that lack electricity, illumination would likely be provided by lamps rather than torches or fires. Fluid fuels would be more available. However, the most likely candidates would be blubber based oils or fish oils. Alcohol would be needed for both drinking and medical applications. Using it as a fuel would be ridiculously wasteful... though some might resort to it if they have the need.

As a final note, shellfish would be rather difficult to find unless you were in quite shallow water. With such an elevated sea level, the available habitats for many species of shellfish would have dwindled drastically. However, they could be cultivated on sub-surface platforms or towed rafts that are attached to ships or other floating settlements.

I hope these thoughts are helpful... I also hope that things in both my rp schedule and my daily life get sorted out enough for me to actually apply to this. I just can't promise anything right now.

Totally down for anyting fantasy/medival I can help with plot and setting. I have a few ideas if you are interested