RECONNOISSANCE NEAR FORT MORGAN, AND EXPEDITION IN LAKE PONTCHARTRAIN AND PEARL RIVER, BY THE MORTAR FLOTILLA OF CAPTAIN D. D. PORTER, U. S. N.

In a former article, on the surrender of Forts Jackson and St. Philip, which appeared in the May number of The Continental Monthly, allusion was made to the efficiency of the mortar flotilla, to which the Coast Survey party, under charge of Assistant F. H. Gerdes, was attached, by special direction of Flag-officer D. G. Farragut. This party rendered hydrographic and also naval service, where such was required, their steamer, the Sachem, being used by the commander of the flotilla like any other vessel under his command. Captain Porter, in his letters to the Superintendent of the Coast Survey, writes, under date of April 29, 1862: "Mr. Gerdes no doubt has written to you and sent you plans. I keep him pretty hard at work. The times require it," &c.

May 16th.—"I have not spared the Sachem, but treated her like the rest of the vessels, putting her under fire when it was necessary. I look upon the Sachem in the same light as I would upon a topographical party in the army, and if I lose her in such employment, she will have paid well for herself."

After the surrender of the Mississippi forts, the mortar fleet met at Ship Island, and the Sachem being directed to join it, arrived there on the 7th of May. Under instructions from the commander, the steamer division of the flotilla stood out for Mobile bar on the 8th, and came to anchor the same evening under the lee of Sand Key, viz.:

Harriet Lane, Com. J. M. Wainwright, flagship
Westfield, Commander W. B. Renshaw.
Owasco, Commander John Guest.
Clifton, Lieut. Com. Charles Baldwin.
Jackson, Lieut. Com. S. Woodworth.
Sachem, As't U.S. Coast Survey, F. H. Gerdes.

It was Captain Porter's design to assemble his mortar vessels, which had started the day previous from Ship Island, at the outer bar of Mobile Bay. He intended then to cross the bar on their arrival, and to come to anchor inside at given distances, for the bombardment of Forts Morgan and Gaines. Those distances were to be ascertained and minutely determined by the Coast Survey party. Unfortunately a very severe northeast storm had been raging for a day or two, which made all headway for sailing vessels impossible, sweeping most of them far out to sea. The commander directed the Coast Survey party to sound the bar, and to plant buoys at the extreme points of the shoals. Messrs. Oltmanns and Harris, each in a separate boat, were sent to perform this duty, and accomplished it by 10 o'clock A. M. The steamer Clifton accompanied the Coast Survey boats for protection, and was running up and down while the spar buoys were planted on the east and west spit, but, caught by the current, she drifted too close to the east bank inside the bar, and grounded hard and fast, just when the attempt was made to bring her round. The tide at that time was ebbing. All efforts to clear her were unsuccessful, and even the powerful steamer Jackson, which was sent to her relief by the commander, had to give up the attempt and leave her exposed to the fire of Fort Morgan. The enemy opened on her directly after she grounded, and some of the shot and shell from the fort struck within twenty yards of her bows. Captain Porter then suggested her relief by the Sachem, which, on account of her light draft, might approach nearer than the Jackson. After clearing her screw, which had got entangled by some hanging gear, the Sachem got under way, and was anchored alongside and to the southward of the Clifton just before dusk. She let go both her heavy anchors, to prevent any dragging from the great strain that must naturally result from an effort to haul off the grounded steamer. A nine-inch hawser was sent to her, one end of the hawser being made fast to the Sachem. The tide had begun to rise by this time, and fortunately at the first strain on the hawser the Clifton floated, and was quickly drawn alongside of the Sachem. There was no time to spare, as the shell and shot from the fort fell very thick; the Clifton therefore got up steam at once, and moved out of range. The Sachem remained to get up her anchors which had been slipped, and was so engaged until 10 o'clock P. M., when she came to alongside of the Harriet Lane. Captain Porter, as well as Captain Baldwin, expressed great satisfaction with the cheerful readiness and seamanship which were shown by the party on the Sachem.

On the 10th of May, at sunrise, it blew a gale from the east, and as there appeared no chance whatever for the mortar schooners to reach Mobile bar, Captain Porter signalled the steam division to return to Ship Island. The Sachem was the second vessel under way, and although comparatively slow, she had now the advantage of a full suit of sails. Early in the evening all the steamers were at anchor again at Ship Island Spit. In the night, between the 11th and 12th of May, the Harriet Lane returned with the commander, who had been in the mean time to Pensacola, and had there taken possession of Fort McRea, the navy yard, and the city, all of which were evacuated a few days previous. Captain Porter at first intended to send Assistant Gerdes, with the Sachem, to Pensacola, to replace the buoys and beacons which had been destroyed by the enemy. It was afterward decided that the party should accompany several of the steamers on an expedition in Lake Pontchartrain and the Pearl river, and in consideration of the light draft of the Coast Survey steamer, and the local information possessed by her officers, he directed that the Sachem should take the lead, and be closely followed by the Westfield, the Clifton, and the Jackson. Early in the morning of the 13th of May, he made signal from the flag ship for the division to start, and at 6 A. M. the steamers were abreast of Cat Island. The Sachem took them safely over the extensive flats, and although there were at times not more than six inches of water to spare, neither of the vessels ever touched the bottom. In the vicinity of Grand Island, a vessel was seen by the lookout, and on reporting to the senior officer of the expedition, Captain W. B. Renshaw, he directed the Sachem to give chase. A gun soon brought her to, and Mr. Harris was sent on board of her, where, on examination, he found no name, no ensign, no papers, in short, nothing but several men. The vessel was taken in tow, and delivered to Captain Renshaw, who despatched her to Ship Island. The steamers got under way again and steamed through the Rigolets, passing Fort Pike, which was then garrisoned by national troops. After entering Lake Pontchartrain in the evening, a steamer was seen some five or six miles distant, and the commanding officer, having ascertained from the Coast Survey party the sufficient depth thereabout in the lake, ordered the Clifton to follow the Sachem. At half past six P. M. a schooner was brought to by the leading vessel, and fifteen minutes later, another. Both were boarded by Messrs. Oltmanns and Harris, and found to be trading vessels with passports from General Butler. When the steamers passed the town of Mandeville, the inhabitants hoisted a large white flag high above the trees; having, probably, no American ensign. After communicating with the United States gunboat New London, all four vessels came to anchor at the Chifuncte river. It was ascertained that the New London was engaged in ferreting out the enemy's vessels in that river, and therefore Captain Renshaw determined to start next morning for the Pearl river, which he intended to examine. At five o'clock A. M. on the 14th of May, the division got under way, led as on the day before by the Sachem. At ten o'clock, the Jackson, getting out of range, grounded and signalized for assistance. The Sachem was ordered to her relief; but in the mean time, the Coast Survey party had furnished information such as would bring the other steamers safely to the mouth of Pearl river, by keeping along the southern bank in the Rigolets. When the Sachem came up with the Jackson, her captain informed Mr. Gerdes that as the transport boat Whiteman (a prize) was expected to pass soon, she would be expected to lighten and tow the steamer off. The Sachem therefore moved on, and reached the Westfield and Clifton at ten o'clock, at anchor near the mouth of Pearl river.

A row of stockades had been set by the enemy quite across that river, leaving only an opening for vessels to pass up and down. This obstruction consisted of heavy pieces of timber inserted vertically in the mud bed, and joined by cross pieces, to which were chained a number of logs so as to float off at right angles. The length extended about three quarters of a mile, and vessels could pass only through the opening, and under the fire of the guns, when Fort Pike was held by the enemy. The expediency of this device is somewhat questionable, as it plainly designated the otherwise intricate channel, and might have enabled a swift steamer to run the batteries without danger of being detained on the extensive mud flats.

At eight o'clock on the morning of the 15th of May, the three steamers weighed anchor, and stood up Pearl river, the Westfield and the Clifton following in the wake of the Sachem. At eleven o'clock, Pearlington was reached, a straggling village. Here two schooners and a small steamer (the William Hancock) were found, and boarded by Mr. Harris of the Sachem; but when it was proved that they had not been engaged in aiding the rebel cause, they were not further molested. The steamers of the mortar flotilla ascended the river about thirteen miles above Pearlington, when the stream became quite narrow, and the turns so abrupt, that further progress for the larger boats seemed to be impracticable. Captains Renshaw and Baldwin therefore anchored their vessels, and went on board of the Sachem, which, on account of her lighter draught and less beam, could ascend higher, and was besides easier to manage. While pushing on with her, it was frequently necessary to fasten her stern to the trees, and to tow her bow around at the very abrupt turns in the river. Within three miles of Gainesville, where the stream became extremely narrow and crooked, with the shores on both sides thickly wooded, the Sachem encountered a very sudden ambuscade, and received a heavy fire of musketry from the eastern bank. This was immediately returned from the vessel by some sixty rifle and musket shots, and discharges of small arms were continued in rapid succession from both sides for some time. The executive officer of the Sachem, Mr. J. G. Oltmanns, of the United States Coast Survey, while on the forecastle directing the crew, was dangerously wounded by a rifle ball in the breast, and fell. He was at once removed to the cabin, and Acting Assistant Harris directed to take his place. This he did instantly, and remained in that position during the whole of the subsequent cruise. As soon as the long guns of the Sachem and the Parrott rifle 20-pounder could be brought to bear, the thicket was cleared by discharges of canister and grape, and the fire of the enemy was silenced. No other casualties occurred on board of the steamer, but many of the crew narrowly escaped harm, particularly those who were near the wheel house. The sailing master and the steersman had their clothes pierced by bullets, and the sides and decks of the steamer were similarly marked in many places. The river, becoming still narrower and more crooked above Gainesville, it was found entirely impossible to force the Sachem higher up. Captain Renshaw therefore directed her to be turned down stream. In this man[oe]uvre, much difficulty was encountered. It succeeded only by cutting the overhanging trees on shore, then backing her into the bank, fastening her stern, and towing her bow around with the boats. While turning thus, one of the Sachem's boats and the Clifton's gig were smashed in the floating logs, and the flagstaff was carried away by hanging branches of the forest. The national ensign, however, was set on the main, and the steamer got finally clear, and stood down the river to rejoin the Westfield and the Clifton. On coming alongside, Mr. Oltmanns was at once transferred, by the kind suggestion of Captain Baldwin, to the Clifton, and being made as comfortable as circumstances admitted, was put under care of Dr. Nestell, the surgeon of the boat. The warm-hearted commander of that vessel will always retain the sincere gratitude of every member of the Coast Survey party for his endeavors in behalf of their brave associate. The doctor probed the wound of Mr. Oltmanns, but was unable to discover the ball, which, by the by, was extracted six months later, by Dr. Lieberman, in Washington City, after it had gradually moved from the breast to the right shoulder blade. Dr. Nestell had no great hopes at the time he took charge of the wounded officer, but thought that with proper care and attention, it might be possible for him to recover. At eight o'clock P. M. the vessels anchored in Lake Borgne, and the next morning, the 16th of May, the whole expedition returned to Ship Island. Captain (now Admiral) Porter visited Mr. Oltmanns, and made suitable arrangements at once for his removal to his friends in New York in the spacious and comfortable steamer Baltic, Captain Comstock.

Between the 16th and 22d of May, the boilers of the Sachem were cleaned, and some repairs made in her machinery, at the end of which time Mr. Gerdes was directed by the commander to repair to the Southwest Pass of the Mississippi, and there to replace the missing buoys and stakes, and to survey the entrance.

Leaving Ship Island on the 22d of May, the Sachem entered the Pass À l'Outre mouth of the Mississippi, and reached Fort Jackson on the 23d in the evening. Here the can buoys and five or six anchors and chains which had been removed by the confederates were found, and brought down and replaced by the Sachem in their original locations at the Southwest Pass. This important inlet of the Mississippi, at present the most accessible and best, was surveyed, a manuscript chart was made by the officers of the Coast Survey, and copies of the same were sent at once to Flag-officer Farragut, Captain Porter, Major-General Butler, and to the Coast Survey office in Washington; at the latter place the chart was lithographed immediately, and extensively distributed in New York and New Orleans.

When Flag-officer Farragut directed Captain Porter to ascend the Mississippi with his mortar flotilla as far up as Vicksburg, the party in the Sachem was again called for. The vessel got under way on the 8th of June, in charge of Acting Assistant Joseph E. Harris, to whom Mr. Gerdes had transferred the command, but unfortunately a few hours after starting she broke her shaft by striking a snag, and was entirely disabled, until extensively repaired. She was towed from Baton Rouge, where the accident happened, to New Orleans, and there turned over to Captain Morris, of the U. S. Navy, commanding the sloop of war Pensacola. The officers and the crew of the Sachem were returned to New York in a U. S. transport steamer. Thus ended the expedition of the Coast Survey party attached in 1862 to the mortar flotilla.

The intercourse and association of the navy officers with the officers of the Coast Survey during the eventful days of the siege of Fort Jackson, the reconnoissance to Mobile, the expedition in Lake Pontchartrain and Pearl river, up to the time the Sachem was disabled from further participation in the operations of that campaign, had cemented warm feelings of attachment and sincere friendship, and it was with a heavy heart the writer of these lines bade farewell to his honored commander and friend of twenty years standing, and to his other associates in the dangers and triumphs of that ever memorable campaign.

Porter now pursues his glorious career as rear admiral of the national navy, and his name has been since, and will be forever identified with Vicksburg, Arkansas Post, Red river, and Grand Gulf. Commanders Richard Wainwright, of the Hartford; Jonathan Wainwright, of the Harriet Lane; W. B. Renshaw, of the Westfield, and Lieutenant Lee, also of the Harriet Lane, have passed away from their friends and associates, consecrating their lives gloriously in our country's cause, but deplored and lamented by their friends. Mr. Oltmanns recovered slowly from his wound, and has served since on topographical duty for the Army of the Potomac. He is now with the Engineer Department of General Banks in Louisiana, where he has proved very useful, and so far eminently successful. Mr. Harris, who is esteemed and appreciated by the officers of the navy and of the Coast Survey, has gone back to his legitimate occupation in the office of the Northwestern Boundary. Messrs. Halter and Bowie remain in the Coast Survey, and are now employed in its duties.

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