the Littoral Combat Ship might be used in unanticipated ways, its initial mission is likely to be control of the waters of the Guinea Coast of Africa. There's a strong chance that over the next one to two decades, the Guinea Coast region will replace the Persian Gulf as America's third-leading supplier of petroleum. (Canada and Mexico, not Saudi Arabia, are our first- and second-ranked foreign suppliers of oil

All petroleum departing the Persian Gulf must pass through the Strait of Hormuz, just 12 miles wide at its narrowest point; in military terms, the Strait of Hormuz is very vulnerable. Oil tankers transiting from the Guinea Coast to the United States would simply sail toward the setting sun and directly into the "blue water," where the U.S. Navy rules.

New York Times, Washington Post and Wall Street Journal haven't reported on the plan for this new class of vessel

see this Wikipedia entry