Interesting Letter from Com. Porter

WASHINGTON, May 24, 1862.

The following interesting letter from Com. Porter to Senator Grimes of Iowa furnishes valuable information concerning the rebel marine monsters in process of construction at and below New Orleans when the city was captured by our forces.  Writing from Ship Island under date of May 6^th, Com. Porter says:

Four rams and floating batteries, such as the world never before saw, have been destroyed in the late attack.  The Louisiana, and invincible steam battery, was set on fire and sent down on the vessels while I was engaged in drawing up a capitulation for the surrender of the forts – a flag of truce flying at the time.  She exploded within three hundred yards of us and sank in one minute, her splendid battery of riffled guns being lost to us.  Her fragments fairly covered Fort St. Philip, and killed a man of theirs in the fort.  There was Southern honor for you.  That vessel was 4,000 tons, 270 feet long, and had sixteen heavy rifled guns, all made in “Secessia.”  She intended to take position that night where she would have driven off all our fleet, for as proof of her invulnerability, one of our heaviest ships laid within ten feet of her, and delivered her whole broadside, making no more impression on her than if she was firing peas.  The Louisiana’s shot, on the contrary, went through and through the above mentioned sloop of war as if she was glass.

The iron ram Manassas hit three vessels before her commander ran her ashore and abandoned her. She has been a troublesome customer all through.

In New Orleans our naval officers found the most splendid specimen of a floating battery the world has ever seen, (a sea going affair,) and had she been finished and succeeded in getting to sea, the whole American navy would have been destroyed.  She was 6,000 tons, 270 feet long, sixty foot beam, had four engines, three propellers, four inches, (and in some places more) of iron and would steam eleven knots an hour.  She cost “Mr. Mallory & Co.” two millions of dollars.  The last one I saw floating by me was a dry dock turned into a floating battery, mounting sixteen guns, and the entire engine was to propel it, hermetically sealed by a thick iron turret against shot.  She was sunk but floated down to Southwest Pass and is now aground on the bar and can easily be raised.

Besides these monsters, the naval part of the enemy’s defenses at the forts consisted of six or seven iron clad gunboats almost impervious to shot, and certainly so against vessels coming bow on.  We had nothing there on our side but twenty frail mortar boats, five sloops of war, nine or ten poor gunboats (in all a little over 140 guns), to contend against two of the most impregnable forts in this or any other country, mounting 127 heavy guns, (many of them rifled) three iron-plated batteries, mounting thirty-one guns, six or seven iron-plated gunboats, and nine or ten things got up for the occasion, soon destroyed and their power never to be known.

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Allow me to send you a perfectly correct tracing of Fort Jackson, made by the coast survey party attached to the mortar fleet.  They acted in the same capacity as the topographical party hold in the army.  Without them our work would have been tedious.  They triangulated every position occupied by the mortar vessels, and it is safe to say that we know to a yard the exact distance of the mouth of the mortars from the center of the fort.  The enemy never saw us except for one day, when one of the divisions of six vessels was placed in sight; getting pretty roughly handled, I moved them under a point of woods, where their masts covered with green bushes, and their rigging with vines, they were invisible to the best glasses. – Our firing was a matter of calculation, and you may judge how accurate it was when I tell you that 1,313 bombs struck the center and solid parts of the works; 3,330 struck in the moat near the foundation, shaking the whole fort to its base; nearly 1,500 in and over the works; and 1,355 struck about the levees, in the marsh close around, and in the paths and near the water’s edge where the steamers attempted to come.  All small boats, scows, and armed barges were sunk, and if the garrison had desired to get away they could not have done so easily.  I never saw so perfect a scene of desolation and ruin, nor do I believe there was ever such perfect mortar practice.  We could clear the batteries whenever the soldiers appeared on the ramparts.  In fact no guns there could be worked.

This sketch may interest your friends in the far West.  It will remind them that the influence of the navy is felt everywhere over this great country, and when the vast riches of the Western states are floating securely and peacefully to the seaboard on the swift waters of the Mississippi, let them remember that it was the navy which opened the doors to a commerce that might have been shut up for a quarter of a century, and that they can dictate free trade now where they might  have been obliged to pay tribute.

With my best wishes, I remain, dear sir,

Yours very truly,

DAVID D. PORTER,

Commanding Flotilla,

Hon. J. W. GRIMES, U. S. Senate

– Published in The Burlington Weekly Hawk-Eye, Burlington, Iowa, Saturday, May 31, 1862, p. 2