Yeah, if topped up the cargo tanks, the Nordwind is just plain to heavy, for hydro foil mode. If you run on 80% load, it should still be possible to run on hydrofoils. If you wan't to transport more, then you just have to use her like any ordinary tanker.

You can als try to redistribute your cargo. By moving it aft (and overloading the aft compartment), a little bit try and error, with the foil controls (it's important that the bow lifts first out of the water, to reduce drag), and a full battery, it could still be possible to lift her fully up. But I never tried it out.

yes

Calm weather?

when fully loaded this thing does not want to hydro foil even with the booster