Worldwide Insurance

[LazySail]

Hello,
I recently own a Lagoon 400 and want to sail around the world.
All (not much) contacts I made until now for an insurance, returned much expensive.
As I can only be at one place at one time, I thought that the price for a Worldwide insurance was around the price for the more expensive country.
But doesn't seem to be the case...
Can someone recommend me a company that could make this kind of insurance?
Or Should I contract insurances locally as I go to the places?

Thanks in advance
Pedro