The Confederate iron-plated ship Merrimac destroyed two Union boats during the Civil War. The Union responded with the ironclad Monitor. Dedicating a statue to the Monitor's designer, John Ericsson, May 29, 1926, President Calvin Coolidge stated: "When the ironclad Merrimac went out on the morning of MARCH 9, 1862, to complete its work of destruction it was at once surprised by this new naval innovation...After a battle lasting four hours in which the Monitor suffered no material damage...the Merrimac...badly crippled, withdrew, never to venture out again...The London Times stated that the day before this battle England had 149 first-class warships. The day after she had but two, and they were iron-plated only amidships. Naval warfare had been revolutionized." When offered payment in 1882, John Ericsson replied: "Nothing could induce me to accept any remuneration for the Monitor...it was my contribution to the glorious Union cause...which freed 4 million bondsmen." John Ericsson wrote to President Lincoln: "Attachment to the Union alone impels me to offer my services at this frightful crisis -my life if need be- in the great cause which Providence has caused you to defend."