Need to make a full Surface from split surface

I have created the hull with network curve but the hull surface is not join/merged. I wanted to make a full surface which turn into one surface and wanted to calculate Hydrostatic & Stability.

Thank you.

Screenshot_2

Upload a .3dm file with the geometry.

Build proper vertical sections with the same amount of control points each, then use “Loft” with the “Loose” option. You can also use points instead of initial and end curves.