Galvanic potential

I have bought and used countless nails and bolts and nuts and washers in my lifetime. Whenever it comes time to buy such hardware, I find myself in that aisle of the hardware store (you know the one: it's lined with small drawers and tubs filled with fasteners), glossing over terms like "galvanized" and "cadmium plated" to make a purchase based on size and price. Oh, how things have changed. For the past week, I've been designing a frame to hold an underwater camera. The camera and frame will form a BRUV, or baited remote underwater video station. It's like its name says: it gets dropped into the ocean with bait and left to film all the creatures that are attracted to the mushed pilchards (mmm, mushed pilchards). The frame will be made out of aluminium (note the extra "i" and pronounce accordingly when speaking to men at the hardware shop) and bolted together with, um, well.... er. What was that about galvanized screws?

So, I've been learning about galvanic potential and oxidation and corrosion and which metals can be in contact with eachother given area ratios and the presence of salty water. It's all quite, uh, illuminating. I've also had to buy a protractor and graph paper; I'm amazed that anyone sells that stuff any more, but thank god they do. I've been using trigonometry (SOHCAHTOA anyone?), which I barely remember since it's been about 15 years since I last thought about it. And I've been trying to think and draw in 3D.

And what have I learned? I have learned that I am not an engineer. And I've had a helluva good time learning that. It's been a nice to pull out the pencils rather than the journals; to draw rather than to type; to think about aluminium fitting together rather than communities of fish species interacting. But at the end of the day, it's very clear that I'm an ecologist.