Epoxy paints are not good barrier coatings. Proper barrier coatings like International's Interprotect are not paints but coatings with a specific design purpose. 5 coats are required for proper protection, and the hull must be dry which takes several months to achieve.
To my knowledge neither Benjamin Moore or Sherwin Williams make marine barrier coatings - I don't think they make marine paints at all.
When barrier coating you want the best protection available, not the least expensive. You are trying to seal the inner layers of the hull structure from moisture which the gelcoat and polyester resin cannot do.
Living aboard in Victoria Harbour