In general, no. Despite the fact that you are not "running a constant charter
business" most countries will still consider it to be a business when you charge people to come on your boat with you. And they will require you to follow all of the same regulations
as someone who is operating their boat for hire every day of every week.
Most countries will require you to be licensed. Most will require your boat to be inspected to a certain standard. Some will have insurance
requirements that you must meet. They may require you to have a business license
. And so on.
Of course, there are a lot of people out there who try to circumvent these laws by claiming that they are only "sharing costs" with their passengers. While the odds of getting caught, if you try this, are relatively low, most countries are onto this particular dodge and if you DO get caught they will not be sympathetic. You may end up being fined, having your boat confiscated, spending time in jail, none of the above, or all of the above. It just depends.
If you do, in fact, only share direct costs for the particular voyage with your passengers, that is usually legal
. But obviously you cannot make any money
doing that--not even pocket money
for future maintenance