A cheap way
How much winter do you have left up there? First is the triage- what doesn't need to be on the boat, what should go some where else (heavy stuff), and what's left. When you know what you have to store, you'll know what you have to build, size and number of compartments. My goal would be reversibility. Your needs may change after a season and resale will suffer, people think they want double berths. Consider a two level approach. I would make hanging storage from the ceiling by placing hooks at the top of the hull and bulkhead that would support the ends of angle iron (the kind with multiple holes in it and is painted) running parallel to the centerline of the boat about 20-30 cm apart. I would hang different size mesh bags from those bars with the light stuff like it was a meat locker. Tie some off higher, some lower. You’ll find what you are looking for pretty quickly. If you need more storage and can't imagine needing the v-berth for romance (just imagine flinging all the mesh bags out into the salon), I would lash plastic crates together to separate the heavier stuff (see link). Cover or remove the mattress, and use a rope from the door jam to the anchor locker wall to keep the stuff from shifting. The crates can stack, if you need more than one level (the bottom level crates lashed to each other will stabilize, but you may want to rope off each level), and use different colors for different items to find them easier. If you would rather build custom teak cabinetry, be sure to post a picture. Dan
