Building a self-hosted “boat management system” Baserow or something else? Looking for an architecture sanity check.

My wife and I are preparing to live aboard and cruise full-time on a sailing catamaran, and I'm planning a self-hosted system to help us manage the boat.

I'm reasonably comfortable with IT, networking, Docker, and running services on my Synology NAS, but I have very little experience with database design or application development. Before I start building something I'll regret maintaining, I'd love some feedback from people who have done similar projects.

**The concept**

I want one central database that supports several interconnected functions:

* **Crew/guest management:** Reusable profiles, arrival/departure dates, travel arrangements, dietary preferences, etc. Guests will join and leave at irregular intervals throughout the year.
* **Provisioning:** Grocery lists, inventory, resupply planning, and historical consumption tracking.
* **Maintenance:** Equipment records, scheduled maintenance, service history, repair requests (squawks), and associated spare parts.
* **Spare parts/equipment:** Inventory, storage locations, part numbers, and relationships to onboard equipment.
* **Cruising/calendar:** Longer cruising seasons, individual offshore passages, watch schedules, guest movements, and recurring administrative deadlines.
* **Documents:** Manuals, procedures, checklists, and other boat information.
* **Analytics:** Eventually use historical data to predict consumption, plan resupply, estimate maintenance needs, and feed information into AI or another analytics tool.

The goal isn't to build an elaborate ERP system. It's to make everyday boat management easier while gradually accumulating useful historical data.

**An example of the workflow I'm envisioning**

We're sailing and realize we've used the last box of pasta. Someone adds pasta to the grocery list through a simple web interface.

When we reach port, I open the list on my iPhone. It shows a suggested purchase quantity, which I can adjust based on what I actually find. I check items off, add unexpected purchases, and leave unavailable items on the list for our next stop.

Completing the shopping trip updates our estimated onboard inventory automatically.

Products need to be flexible: different brands, package sizes, and units should all map to the same underlying inventory item. Eventually, barcode scanning would be great, but it shouldn't be required.

Over time, occasional physical inventory counts, purchase history, and the number of people aboard should help us estimate actual consumption rates and improve future provisioning recommendations.

**The technical environment**

* Synology DS925+ NAS with 32 GB RAM, already running Docker containers.
* Existing locally hosted crew portal for accessing onboard services.
* iPhones will be the primary mobile interface.
* Internet via Starlink, but connectivity may be intermittent or expensive offshore.
* Google Calendar and Microsoft Excel/Word are tools we already use and would like to integrate where practical.
* Two primary administrators (my wife and me), with rotating guests/crew who need simple forms or limited temporary access.

**Important design requirements**

1. Self-hosted, preferably open source. I'm willing to pay for software if it meaningfully reduces development and maintenance or provides the right functionality.
2. Offline-first, at least while connected to the boat's local network. Ideally, some mobile workflows (especially shopping lists) would work away from the boat without connectivity and synchronize afterward.
3. Low-code/no-code where possible. I don't want to become a full-time software developer to maintain this.
4. One authoritative source of operational data, with relationships between crew, dates, equipment, inventory, and maintenance.
5. Good APIs and export options so the data isn't locked into a proprietary system.
6. Simple, mobile-friendly interfaces for everyday tasks.
7. Sensible authentication and permissions, particularly for sensitive crew