"We simply don't know and really hope for more tips, " Shields said.

CNN: Missing teen's parents help other families cope

On a busy and successful charter yacht you can hope to make tips of around 5 to 15% of the cost of the charter per week divided amongst the crew.

CNN: Confessions of a superyacht worker

And in the true spirit of Foursquare, we hope you'll add your own tips to the venues we've chosen.

CNN: teams up with Foursquare for World Cup

In general, a slightly higher salary is offered if the yacht is private with the hope if you work on a charter that you will make up your salary with tips.

CNN: Confessions of a superyacht worker