Ian, are you translating directly from the Japanese version? I´m asking because your translation is quite different from the Portuguese, Brazilian-Portuguese and French versions (they don´t say anything about the "I had gotten hold of" part)
Yup, here is literally what the Japanese says:
I had gotten into my hands (i.e. had managed to find) a bottle, I stuffed (i.e. with a little effort, that's what the Japanese verb "tsumeru" means, like stuffing a teddy bear or a turkey) a message into it, and then gently put it into the sea and let it float away
Other language translations may have been done from the French, I suspect...
But I'd be happy to answer any questions about it...