Friday, February 14, 2014

"There being every reason to expect a visit...": Dahlgren's countermeasures against torpedo-boats

Monday marks the 150th anniversary of the sinking of the USS Housatonic by the H.L. Hunley. Rightfully so, the event is mainly remembered as the first successful submarine attack, foreshadowing the weapon's wide spread and significant use in the 20th century. At the same time the Confederates were preparing the H.L. Hunley alongside "David" torpedo boats, the Federal South Atlantic Blockading Squadron prepared and employed some of the first submarine and torpedo-boat countermeasures.

Many of those countermeasures were described in an order from Rear-Admiral John Dahlgren, issued on January 7, 1864:

I have reliable information that the rebels have two torpedo boats ready for service, which may be expected on the first night when the water is suitable for their movement. One of these is the "David," which attacked the Ironsides in October: the other is similar to it.

There is also one of another kind, which is nearly submerged and can be entirely so. It is intended to go under the bottoms of vessels and there operate.

This is believed by my informant to be sure of well working, though from bad management it has hitherto met with accidents, and was laying off Mount Pleasant two nights since.

There being every reason to expect a visit from or all of these torpedoes, the greatest vigilance will be needed to guard against them.

The ironclads must have their fenders rigged out and their own boats in motion about them.

A netting must also be dropped overboard from the ends of the fenders, kept down with shot, and extending along the whole length of the sides; howitzers loaded with canister on the decks and a calcium [light] for each monitor. The tugs and picket boats must be incessantly upon the lookout, when the water is not rough, whether the weather be clear or rainy.

 I observe the ironclads are not anchored so as to be entirely clear of each other's fire if opened suddenly in the dark. This must be corrected, and Captain [Stephen C.] Rowan will assign the monitors suitable positions for this purpose, particularly with reference to his own vessel [USS Ironsides].

It is also advisable not to anchor in the deepest part of the channel, for by not leaving much space between the bottom of the vessel and the bottom of the channel it will be impossible for the diving torpedo to operate except on the sides, and there will be less difficulty in raising a vessel if sunk. 

Nets, patrolling boats, close-range guns, and spotlights - all components used to counter submarines in later conflicts. While convoy formations were not applicable to station-keeping off Charleston, the orders specified a defensive formation designed to repel attacks. In short, a respectable list of anti-submarine measures. Everything save perhaps some depth charges.

Clearly directed to the skippers of the ironclad vessels, which primarily operated in the main ship channel off Morris Island, the orders did not address those ships operating further out from the harbor mouth on blockade duty. This was a miscalculation. One way to look at the sinking of the USS Housatonic, as the Hunley scored the first submarine victory in history, the Federals suffered the first failure to defend against that weapon.  In that light, Dahglren's orders of January 7, 1864 are among the first pages in a long story about countermeasures taken to defeat the submarine.

(Citation from Official records of the Union and Confederate Navies in the War of the Rebellion. ; Series I - Volume 15: South Atlantic Blockading Squadron (October 1, 1863 - September 30, 1864), pages 226-7.)

1 comment:

  1. That the Federal vessels outside the bar were apprised of the operations of the Confederate torpedo boats is documented. See the OR of the Navies, Series I, vol. 15, page 241: Admiral Dahlgren sends an order to Captain Green of the USS Canandaigua, the vessel which would come to the assistance of the Housatonic a month later, when sunk by the H.L. Hunley.

    "Sir: The Navy Department has received information that the rebels have a plan to blow up this fleet, and considers it of sufficient importance to inform me thereof.

    I can hardly think that the design would extend beyond the ironclads that constitute the inner blockade, for the outer vessels are distant and difficult of access.

    Still, it would be unwise to omit any proper precautions, and I therefore advise that you will take such measures as may suffice to defeat any attempt of the kind.

    I enclose for your information the directions prescribed to the ironclads. You can use these or whatever else may seem more adaptable to the purpose.

    Let this be circulated among the commanders of the vessels outside for their guidance."

    The vessels outside of the bar did, indeed, heed the warnings. The Housatonic was on high alert the night that the Hunley approached, and had Mr. Cornthwaite at the bow heeded the alarm of lookout Robert Flemming, may have had enough time to back away from the submarine. By the time the sub was independently sighted by officer Crosby, valuable time was lost before his orders were promptly obeyed. The general quarters rattle was sounded; the anchor chain was slipped through a contrivance to make it immediately unfastened, the boilers had a full head of steam per orders, and the large naval guns were loaded and ready to fire, Unfortunately for the Housatonic, the Hunley was by then too close to depress the guns sufficiently, and down went the Housatonic when the sub placed her torpedo.

    The outer blockade ships were ready, but the Hunley's stealth technology was superior to their preparations.