Malizia has a single-skin hull bottom full length. For reference, this is a thin single-skin carbon shell supported by many stringers, like an aluminium/steel boat. Many other boats have single-skin from stem to midships, or just aft of this. Topsides, deck, bulkheads etc will be a honeycomb sandwich panel. Also, the latest imoca rule does not allow honeycomb in the hull bottom.It’s possible there are more areas of solid laminate, but that boat is absolutely cored. You could not make the boat stiff enough with solid laminates everywhere, unless you were cool with it weighing 10x what it should. It’s also possible that he opted for foam in areas where other boats went with nomex. A lot of boats (not just imocas) have had to scrape out delaminated nomex and replace with foam like Guyot Environment over the years. You can engineer honeycomb laminates to be pretty bombproof, but more often than not, when there is core shear failure in a bottom panel it’s a honeycomb laminate. I definitely subscribe to the Boris approach as far as making the structure a bit heavier to avoid having to make structural repairs. It’s interesting to see these repairs be done with crews aboard vs when skippers are on the Vendee. They can push much harder and still affect repairs, in contrast to the complete clusterfuck that occurs when someone is all alone. Not only is it slow on the course, but even with the crewed boats, it’s clearly exhausting to the crews.
The whole single-skin bottom concept has been around for a wee while now, with heaps of images and videos that show it. You can not have hull shell core failure if there is no core..
The stringers that then support the single skin however become critical..