So you are traveling around the world in your through satellite connected sailing yacht. To finance your trip you blog and develop websites. Where is this work taxed? Is it tax free, or am I obliged to pay taxes in the country where my yacht is registered?
There is no legally binding body that collects taxes on international waters, as they are not actually under the jurisdiction of any state.
As it happens, a great many yachts sail under the flag of ominous countries such as Puerto Rico or the Bermudas where there is no income tax for non-residents, i.e. if you are not actually setting foot on the territory.
The list of these tax havens is shrinking, though.
If you actually meant to ask where you could have a share of your income properly confiscated, it depends on the non-tax-haven-country where the yacht is registered. It's my understanding that there are almost as many tax codes as there are actual countries. Some jurisdictions will require tax statements from the moment you are registering any property, others will only ask you for tax statements if you actually spend time on their territory for at least 6 months plus 1 day per year. Within that range there are many divergent opinions what exactly constitutes fair taxation.
Your income could be taxed by the country where your yacht is registered but also by a country where most of your clients/income come from, where you own a house and left other properties, or by the country of your citizenship, etc. There is no overarching definition of tax residence, it's up to each country to define, within the bound of the treaties they negotiate with each other.
In practice, you will also need contracts with your clients (I am assuming you are freelancing) and a bank account somewhere to receive payment and use the money easily. That could also have tax consequences.