Hydrogen and oxygen tanks gave an error converting to ship, but did detach. Wind turbine will not because it can not be on a ship I guess.
Love the Scenario.

The bounding box of the wind turbine is much larger (3x3x3 Big Blocks) than the optical model. Try making the hole around it bigger. If you are unsure place large blocks around it to have a better understanding which part is still in the dirt. Also the thin frame which appears when you point at it with a welder can be helpful. Windturbines can be on ships, but they only work when the grid is locked via landing gear.

I've a solution for this:

- Attatch the large grid block with a magnetic plate coming out from your small grid rover
- Dig below being careful to not leave any small piece of terrain 'till the block is floating
- Add a few cubes to make it reach terrain again and grind those blocks
- Move it freely with the magnetic plate

*Note for windturbine.. sometimes dirt can stuck beneath the wings, to drill it out safely, repair the turbine as much as possible, hold drill close to the dirt even if it's damaging the turbine itself, after a longer while than expected, the AoE will take out the dirt and u can just repair again the turbine.

Stef's solution is close to what has worked for me.
I had a LG grid cargo container that would not detach. I had dug a significant amount around it so it was floating in air. I had attached my crane but still didn't come free.
What eventually worked was attaching 3 or 4 blocks to the cargo and then grinding off the cargo again. When I did that it successfully detached from all blocks.