Boat and shipbuilder seeks business solution

I am looking for software to manage my North German company. My work is very project-oriented. There is a certain amount of "background noise" that serves to maintain the company. In addition, there are projects that are worked on over a period of 4 weeks to 3 years with up to 15 employees. To give you an idea of the scale: in 2019/20, 25,000 working hours were recorded, with a turnover of €1.8 million. "Background noise" in 2021 is approx. 2,000 hours with a turnover of €100,000 so far. I work in the boat and shipbuilding industry. Most of the projects are individual prototypes and one-offs. Currently, Windows laptops with a small network and mobile devices are used. Accounting is done by the tax advisor using DATEV Online.

Specifically, I am looking for a solution to improve my controlling that meets the following requirements:

• Quotation preparation (individual calculation must be possible, not just m² price for tiles!)
• It must be possible to change quotations
• Order generation
• Change of current order (change order, construction freeze, on-hold costs)
• Query tool performance levels, project controlling
• Invoice generation
• Open items
• Liquidity planning
• Hourly billing rate
• Time recording (also from mobile devices!)
• DATEV Online interface possible?!
• DMS
• Web-based solution (with the option of working offline)

Three fixed (one of which is a “chief admin”) and two mobile software workstations are planned.