Lovely. And, er… what was it striking?
At a guess a Tanker, but it's hard to see in an image of that resolution. I imagine ships get hit quite often by lightning, so I'd be suprised if tankers aren't designed to deal with it. After all, they're essentially made of metal with a very good earth connection, which is why they get hit, and why it'll likely all dissipate directly into the sea.
Good lucky shot though. Were you using a long exposure to catch that, or just very very lucky?