"Foreign flagged", I am interpreting that as non-US/Canadian as opposed to a US flagged boat in Antigua.
You may find US based insurance more expensive than non-US based polices. As a non-North American boat you will qualify for coverage from Pantaenius Europe (UK?). This is different from Pantaenius America.
You might also want to consider United Insurance out of Barbados - Anjo Insurance in Antigua is an agent (agents on most islands).
You may find some resistance to the Caribbean agents covering a trawler as there are so few trawlers here that the companies are cautious.
There are of course benefits in having a US based insurance company. You can make that decision.