(click photo to visit Altrec page - this model is about $52)
Ah, Pelican cases. I don't know how I would live without these. They are marketed primarily for heavy duty protection of expensive gear like cameras, video, and computers... but they make excellent substrates for integrated equipment packaging. In the brutal environment of a kayak or other boatlet, protection on this scale is essential.
To take a look at some of the things I've done with these, check out the systems on board Bubba, my geeked-out inflatable kayak. The black Pelican case lashed to the bow carries a 2-meter amateur radio transceiver, a packet TNC for data communication, headless GPS receiver, USB-serial interface, solar power management system, 2 sealed lead-acid batteries, AC charger, inverter, charging station for AA NiMH batteries, a custom bicolor navlight made with Luxeon high-brightness LEDs and a constant current source, and mounting for a radar reflector. And that's just one of the three Pelicans on board!
(And for a truly hard-core Pelican-based packaging project, check out our WANDER box, an embedded Linux-based data collection system.)
This plastic is robust but easy to mill and drill, and it accepts silicone sealants. I've mounted waterproof connectors and switches, added external and internal mounting fixtures, and even used them as substrates for control panels. I have yet to find another product line that is this accessible and useful for harsh-environment equipment packaging.
(click photo to buy from West Marine - about $9)
I am so glad to see these finally available through reasonably accessible channels, rather than just industrial supply! Vapor-Phase Corrosion Inhibitors (VpCI or VCI, depending on whom you listen to) are extremely useful inside enclosures that live in a salt-water environment, as they slowly outgas a substance that creates a molecular film on all exposed metal surfaces. This gives you a level of protection that is hard to achieve with manual methods like sprays, and it's cheap and easy as well.
This brand comes in three sizes, good for enclosed spaces of 1, 11, or 400 cubic feet. I use the strips inside the Pelican Case aboard Bubba, referenced above. Think of it as very cheap insurance for your electronics... not as robust as a conformal coating, but easy to retrofit to any electronics packaging job.
(click photo to buy from West Marine)
Ah, Boeshield. There's a mystique about this stuff that sets it way apart from the standard sprays from your local hardware store: developed by Boeing and used in boatshops all over the world, it has the amazing ability to attach itself and cling tenaciously to exposed metal surfaces... without being oily. It leaves a subtle waxy film that lasts for months, and, well, it just works. Get some and use it on your boat hardware; you won't regret it.
You can also use Boeshield as a penetrant and general lubricant, and it's not a bad idea to coat stainless hardware (as you may have discovered, the term "stainless steel" has dozens of meanings due to the wide range of alloys out there, some of which interact quite unpleasantly with each other in the presence of the universal electrolyte in which we like to sail and paddle). This doesn't replace a tenacious anti-seize compound on the threads, of course, but for everything else in the corrosion-prevention domain it is wonderful.