They can, the problem is that if you declare this as different parts then you will have to pay taxes accordingly to the chosen HSCode for each one in the declaration.
If you search for the HSCODE you will find that offshore oil and natural gas drilling and production platforms have their own, 8431434000, which means if you declare only this one you will pay no taxes.
If you search for the HSCODE you will find that offshore oil and natural gas drilling and production platforms have their own, 8431434000, which means if you declare only this one you will pay no taxes.