Considering you can provide as many details on HOW you got stranded there (flight numbers, cruise ship name etc.) as possible and add details about WHERE you got stranded, I think that would help search&rescue to at least narrow it down... or maybe you are very lucky and the place has some pretty unique characteristics?
I think the biggest problem would be actually getting the people who find your message to turn it in to the police or so and then you got to hope they won't just throw it away or wouldn't even know where to forward the message to.
I think the biggest problem would be actually getting the people who find your message to turn it in to the police or so and then you got to hope they won't just throw it away or wouldn't even know where to forward the message to.