[@Ceta de Cloyes]
I would say that you can take some creative liberties, if you really need to. I would much rather you play the character your heart is set on and that you put so much work into. This RP is inspired by the Waterworld movie, and an anime called, [url=https://www.google.com/search?tbm=isch&source=hp&biw=1600&bih=789&ei=1XMZXvehEJez0PEPhdaooAo&q=Gargantia+on+the+Verdurous+Planet+ship&oq=Gargantia+on+the+Verdurous+Planet+ship&gs_l=img.3..0.2291.2291..3603...0.0..0.82.82.1......0....2j1..gws-wiz-img.CJ7tuBJJkaw&ved=0ahUKEwi34OP9_frmAhWXGTQIHQUrCqQQ4dUDCAY&uact=5]Gargantia[/url] on the Verdurous Planet that has more advance tech. Technologies are not completely lost, for instance the Dominus Ship Jackal is a ship that specializes in buildings/smithing/metal kind of stuff so they would have a forage of sorts. I don't know much about modern black smithing so bare with me. 

Also the great flood happened in 2055, and people prepped a bit in advance for it. So 2020 tech + 30ish years means there would have been advancements. So like a solar powered saw and welding gear or something for tools. It would be rare to have this tech off the Jackal ship or Drevni cities, but it is around. Other tools like knifes, wrenches, and nails could be made from carved bone or stone. Whale oil can be used for flames, and blow torches if fuel is an issue. 

As for wood harvested from the ocean floor, I googled and this is what I [url=https://answers.yahoo.com/question/index?qid=20120620105605AA2PwqB]got[/url], so hopefully that helps. It's only been 350 years since the flood, and this site is saying wooden ships from 1500 years ago are still found in the black sea. And yes metal is the primary thing scavenged from the bottom of the ocean, from sunken cities and other ships.