For some countries, we are only allowed to show charts for free for a limited amount of time. This varies from country to country and is due to how chart licensing in certain regions works. This restriction is beyond our control and we're negotiating with the hydrographic offices to be more forthcoming and allow people like you to test the charts better before making a purchase. We strongly believe in the "try before you buy" philosophy and we're doing everything we can to make this happen for all of our users.
When browsing on those areas, you should see a notification when you launch the app that tells you about this situation