Freelancer:
andreible
underwater blueprint
For the background I combined two of your suggestions (water & blueprint) in a cool, unique and suggesting picture for your company. Besides that, I kept the design simple, with the elements you requested and some basic extra info for the people who are interested. All the important elements are on the top half so they are all visible all the time. I could also add some contact info if you think it would be useful and you provide it for me. Hope you enjoy it and if you have any suggestions please let me know. Thank you !