Foreign tourists in veils seen on a passenger boat with the Iranian flag amass in the waters of the Strait of Hormuz on May 2, 2017 near Hormuz Island, Iran. An oil tanker is seen on the move in the background.

If Iran closes the crucial Strait of Hormuz one former U.S. admiral with in-depth knowledge of the challenge says the Navy is prepared to unblock it, quickly.

“In the event Iran choose to militarily close the Strait of Hormuz the U.S. and our Arabian Gulf allies would be able to open it in a matter of days,” said former Adm. James Stavridis in a telephone interview with CNBC on Monday.

Beyond his time commanding ships and sailors at sea, Stavridis also served as NATO's supreme allied commander and as a top Pentagon planner during the early years of the war on terror after the Sept. 11th attacks on the United States before becoming a security analyst for NBC News.

While most military planners acknowledge that Iran could temporarily close the straits which serve as a waterway for an estimated 30 percent of the world’s oil supply, most also agree the U.S. Navy is capable of unblocking the strait.

Iran’s navy is vastly inferior to the U.S. however it possesses hundreds of small but very fast attack boats. Military planners warn Iran is capable of using these vessels to swarm larger and less maneuverable American ships. There’s also fear those boats would be used in waves of “suicide attacks at sea.”

Stavridis’ confidence the U.S. could reopen the Strait of Hormuz is tempered by the possibility of those “small boat attacks” saying that even once the waterway is reopened “there is the possibility of ongoing use of mines and diesel submarines and the use of other surreptitious methods by Iran that would likely close the Strait on and off again, but the U.S. Navy would be prepared for those eventualities.”

Programming note: For more from former Admiral James Stavridis, tune into "Power Lunch" on Monday at 1 p.m. ET.