Importing Parts & Materials to EU without Paying VAT

[Silver Moon]

Hello Fair Community:
I am purchasing a newly built boat in France and could use your community input:

I'm considering hiring an important agent, and sending a container from the United States. Many of the upgrades we want including Solar Panels, 48 Volt Lithium batteries, an OC tender, US made tools and parts are not available in France or the manufacturer isn't available in France.
Our understanding is that since our boat is a "Vessel in Transit". We plan on being out of the EU within the 18 months. Any parts and materials for the boat are NOT subject to the VAT.
Now my question.
Do you or anyone you know have experience with using an importing agent to help with customs in the EU?
Did the exclusion of the VAT apply to parts and materials for a Vessel in Transit?

Thanks for any input and FAIR WINDS!