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SEAC: The Search for Battery Halleck


PRIMARY DOCUMENTS (Page 4)

Page 1, 2, 3, 4, 5

[Excerpts from] Report of Lieutenant T. B. Brooks
New York Volunteer Engineers
Camp of the Volunteer Engineers
Hilton Head, S.C., May 1st, 1862
To: Brig.-Gen. Q. A. Gillmore
Commanding on Tybee and Cockspur Islands, Ga.

General:

In accordance with your instructions, I have carefully examined, since the bombardment on the 10th and 11th ult., the condition of the batteries erected on Tybee Island, Ga., for the reduction of Fort Pulaski, and have the honor to respectfully submit the following report on the same, with remarks and deductions of my own, which you kindly gave me permission to add.

I. MORTAR PLATFORMS

For plans and dimensions see Plate IV [Figure 4, this volume].

The 13-inch mortar (1861 pattern) platforms used, may be described in general, as consisting, (1) of a flooring of three inch pitch pine plank, laid on ground well rammed and leveled; (2) on this flooring was placed a timber structure varying in the different platforms, but similar to the rail platforms....The chief difference was in the larger timbers used in our platforms, and in the fact that the center sleeper or cross piece was always omitted, except in some instances, blocks between the rails were used; also as our platforms were decked small outside rails or stringers, to support the ends of the deck, plank had to be introduced. [This is very unclear.] (3) On this framework a decking of "uniform stuff" furnished by the ordnance department, or common three-inch plank, was placed perpendicular to the line of fire, and fastened down in most cases, by side-rails, with four bolts in each.

Pickets three inches square and three and a half feet long, were freely used to stay the platform.

Plates of iron four and a half feet long, four inches wide by one-half inch thick, inches, [another unclear comment] were fastened on each platform, on which the eccentric wheels of the mortar-beds rested. How well this plan answered will appear from the following facts...

3. Burnside Battery (One 13-inch Mortar)

This platform is apparently in as good condition as the day it was put down.

Sergeant J.E. Wilson, U.S. Engineers, commanded this battery during the bombardment. He took care to fire the mortar in different parts of the platform, thus distributing the pressure and wear. The mortar was run forward nearly to the front of the platform, and then fired a number of times without being run in battery, until the recoil had carried it nearly to the rear of the platform, &c.

4. Sherman Battery (Three 13-inch Mortars)

...It is proper here to observe that in the Sherman and Burnside batteries, the platforms rest on a blue clay or mud mixed with sand and shells, while in the others fine pure sand only is found [implying this was the case for Battery Halleck as well].

5. Halleck Battery (Two 13-inch Mortars)

Both the platforms at this battery are like the Burnside, apparently uninjured....

The following summary embraces the most important facts relating to the mortar platforms constructed on Tybee Island:

1. The new pattern (1861) 13-inch mortar, and the 10-inch siege mortar, require platforms of about the same strength....

2. A platform built of plank alone, as above described and figured [Figure 3, this volume],...will not stand the fire of 10 or 13-inch mortars.

3. A "rail platform," decked over and resting on a plank-floor, was not in the least injured, except in its decking.

4. Pickets, three and a half feet long, and well driven [another archaeological test implication], will not prevent platforms, or their decking, from moving backward from the recoil.

5. That platform from which the mortar was fired in different positions, the Burnside, is least injured; although it was fired more than an average number of times....

6. Sand worked into, and tended to keep open horizontal joints in the platforms, e.g., the front and rear deck plank.

7. The wear on the deck plank of the 13-inch mortar platforms, where the eccentrics of the mortar-beds rested and rolled on the iron plates, is scarcely appreciable.

8. Three-inch pitch pine planks, twelve inches wide, make as good decking as uniform plank prepared especially by the ordnance department.

9. The injury to deck planks, from the square sharp corners of the iron-shod manoeuvring handspikes is great, and will soon destroy them.

10. Side rails, well bolted down, the bolts extending into the timbers of the substructure, can only be depended upon to secure the decking.

11. It is important that the different parts of a platform be well fastened together by lockjoints, pins, and bolts, so as to make a unit.

12. The earth on which the Sherman and Burnside platforms rest, is a blue clay, or mud, mixed with sand. All the others are built on pure, fine, quartz sand....

Mortar Platforms Described in "Ordnance Manual" and "Heavy Artillery"

1. A platform for "Siege Mortars" is described on page 51, "Ordnance Manual," as consisting of-"Wood: 6 sleepers, 18 deck planks, 72 dowels." "Iron: 12 eye-bolts" [possible archaeologically recoverable if left behind].

2. Another, or perhaps the same "Platform for a Mortar," is described and figured on page 105 and Plates 8 and 21, "Heavy Artillery," thus: "The mortar platform is composed of only half the number of sleepers and deck planks required for the gun or howitzer platform. It is laid level and the front and rear deck planks are connected by eye-bolts to every sleeper" [possibly archaeologically recoverable if left behind]....

III. REVETTING.

Four methods were used at Tybee:

1. A stake and brush revetting, made by driving stakes eight feet long and three inches in diameter, two feet into the ground, stakes being placed one foot apart and sloping three on one. This row of stakes was anchored at the top by a rail in front, extending into the bank at each end, and well fastened by pickets. Behind these stakes, small brush of different kinds of wood, having leaves on them, was packed, the earth of the parapet being built up at the same time. A fascine was placed on top and picketed.

This revetting allowed the dry sand to run through, and failed chiefly on this account. If mud or clay had been laid up with the brush, this plan would probably have worked well for four or five feet in height....

2. A rough hurdle work like the above in every particular, except, in most cases, no anchoring at the top was used, and the brush was rudely woven between the stakes.

This plan also allowed the sand to run through, and in every instance where no anchoring was used at the top-the support depended upon, to hold up the revetting, being the hold of the upright stakes in the ground below-the revetting failed, by being more or less pushed over.

3. A sod revetting was used in the Lyon battery, made of rough sods-wall one foot thick, six feet high, and sloping 2 on 1....

4. Fascines put up in the usual manner were used in the Totten battery, the fascines being made and anchored with withes. It leaked the sand very little, but did not sustain the earth. Part of it came down the first day, and the whole was in very bad condition at the end of the fight....

From the above I believe the following rules should be observed in revetting under similar circumstances:

1. All revetting for mortar or gun batteries should have a slope of 2 on 1.

2. For sustaining sand, the revetting must be almost watertight.

3. Anchoring at the top is absolutely necessary, to secure revetting, whatever be the material.

4. Anchoring pickets for fascines must be driven at least as far back into the bank, as the fascine is above the foot of the revetting, and the same rule observed in anchoring any revetting.

5. Tarred rope or wire should be used in this region, to make and anchor fascines.

6. Of the materials used, sod was found best, fascine properly anchored would be next, and the stake and brush put up with mud, last....

VI. MAGAZINES

The timber used for the frames, was four by eight inch scantling. The bents (frames) were usually eight feet wide, and five or three feet high, resting on mudsills of the same stuff, one under each post. The bents were placed three feet apart horizontally, and were framed at the corners....

The sheathing and flooring were made of one and a quarter inch plank; two thicknesses being used on the top and one elsewhere. On this shell, seven feet of earth was placed, its sides sloping one on one and a half.

Entrances, with one and two doorways, were used, all so placed that if a shell burst outside, its fragments, moving in straight lines, could not reach the interior. Adjoining the magazine, the entrance [anteroom or antechamber?] was made five feet wide, to be used as a filling room for cartridges, and was arranged with shelves for cartridge bags.

The frames above described were not found strong enough, giving indications that they would fail by the breakage of the beams supporting the roof, and by the splitting of the shoulders of the posts on which the cross-timbers rested. Both difficulties were, in part, remedied, by placing an upright post in the centre of each bent, reducing the bearing of the cross-pieces supporting the roof to four feet, and relieving the vertical pressure on the side posts.

With this addition, none of the magazines failed, but there was evidently not surplus strength enough....

What effect a heavy mortar shell falling on such a structure, might have, was not experienced at Tybee.

The same difficulty was experienced in the magazines as in all structures where fine dry sand is exposed to the wind. It blew off very rapidly, thus not only diminishing the cover on the magazine, but filling up the covered ways, &c., &c. No permanency can be obtained except by sodding, or spreading over the surface a heavy coating of manure, which will cause grass and grain to grow.

VII. SPLINTER PROOFS

Splinter proofs, in which the men forming the reliefs off duty might repose in comparative safety from the effects of shot and shell fired from guns, were built of pine logs, mud, and sand. Posts, four and a half feet long, were set in the ground, three feet apart, and of such slope as to be perpendicular to the rafters. On the top of these posts a longitudinal cap or plate was spiked. The rear revetting, about one foot high, was sustained by strong pickets, driven in the ground two feet, and standing two feet apart....

The rafters were laid in juxtaposition, the most prominent inequalities being hewn off to make better joints. Mud was plastered over the cracks, which made them completely sand-tight. Over this roof of timber three feet or more of sand was piled.

The longitudinal stick on top at the front edge of the rafters, to prevent the sand from running down in front, might advantageously be replaced by fascines or sand-bags.

Cross-traverses, of a double thickness of this uniform pine stuff, were placed at equal distances along one of the splinter proofs, intended to intercept fragments of shell, should one from a mortar fall through the roof and explode in one of the compartments. These would also serve to divide the space equitably among the occupants or reliefs....

These structures should evidently be erected so high that the floors may be dry at all times, and should be placed out of the line of fire of the enemy's batteries; hence midway between our own batteries would be the safest place, if the batteries are near together, as at Goat's Point, Tybee Island. For cross-section of splinter-proof shelter, see Plate III (Figure 3 in this volume).

I am, with great respect, your most obedient servant,

T. B. Brooks
1st Lieut. N. Y. Vol. Eng'rs.
(Gillmore 1988:81-95 [1862])

Appendix 1 (Page 5).

Appendix 1: Primary Documents (Page 5)

Page 1, 2, 3, 4, 5

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