I use a plastic tool box with a single, plastic tray and metal latches from Ace Hardware. It stows under the starboard settee. That locker does get some condensation, but my tools are not rusting, and stay dry inside the tool box.
I live in a humid area, on the Chespeake Bay. I'm not using any silica packs or preservation spray. I have an assortment of screwdrivers, sockets, ratchets, vise grips, pliers and hex keys. I don't carry power tools.
I've been into engine mechanics for years, and there is only one penetrant that I trust anymore: Kroil, or if you prefer, Aero-Kroil (spray form of Kroil). It's far superior to PBlaster, Liquid Wrench or WD-40.
Use the right snake-oil for the right problem-
Kroil- Blasting rusted fasteners and parts free from each other.
Electrical contact cleaner- Exactly what it says.
WD-40- Lubricating/cleaning slightly rusty, but still moveable fasteners and parts with tight clearances.
3-in-1 Oil- Heavily lubricating hinges, and engine parts that have looser clearances.
White lithium grease- For parts that require a sticky, heavy lubricant that is heavier than oil.
Sailkote/McLube- Lubricating blocks, sheaves, sail cloth, sail track slugs, travelers and other deck hardware.
S/V Old Shoes
1973 Pearson 30 #255