Chapter VII: Mortars

444. TITLES OF MORTAR CREW.

(See Diagram 1.)

No. 1. First Captain.
No. 2. Second Captain.
No. 3. First Loader and Trainer.
No. 4. First Sponger and Trainer.
No. 5. Second Loader, Front Eccentric Trainer.
No. 6. Second Sponger, Front Eccentric Trainer.
No. 7. Left Circle Eccentric Trainer and Shell-carrier.
No. 8. Right Circle Eccentric Trainer and Shell-carrier.
No. 9. Left Circle Eccentric Trainer and Shell-hoister.
No. 10. Right Circle Eccentric Trainer and Shell-hoister.
No. 11. Rear Circle Eccentric Trainer and Shell-hoister.
No. 12. Rear Circle Eccentric Trainer and Shell-hoister.
No. 13. Powder-man.

During exercise or action, Nos. 9, 10, 11, and 12, in addition to their other duties, will hoist up shell from below.

445. IMPLEMENTS AND EQUIPMENTS.

-----------------+--------------------------------------------------------- ARTICLES. | WHERE THEY ARE PLACED. -----------------+--------------------------------------------------------- Handspikes. | Two on each side of the bed against the cheeks, leaning | upon the manoeuvring-bolts, the ends towards the | vessel's sides, and those of the front handspikes even | with the front of the cheeks. | Haversack. | Containing fuzes, and a pair of sleeves, attached to | the tompion. | Tube-pouch. | Containing the priming-wire, friction-tubes, and | lanyard, attached to the tompion, and lying on the | mortar. | Gunner's Pouch. | Containing gunner's level, gimlet, vent-punch and | chalk, attached to tompion. | Quadrant. |} Plummet. |} Scraper. |} In a basket between the cheeks of the mortar-bed. Wiper. |} Shell-hooks. |} | Tompion. | In the muzzle. | Quoin. | Under the mortar upon the bolster, with handle to | the left. | Maul. |} Wrench. |} With the basket. Pincers. |} Broom. |} -----------------+-------------------------------------------------------

Directly over each mortar must be rigged a gun-tackle purchase-whip, with seven-inch block, to whip up and lower the bomb into the mortar.

One empty bomb and one empty cartridge-bag must be ready for drill.

D. Van Nostrand Publisher. Julius Bien, pr.]

MANUAL EXERCISE.

XIII-IN. MORTAR.

446. WORDS OF COMMAND.

I. "SILENCE!"
II. "CAST LOOSE AND PROVIDE!"
III. "TRAIN!" (RIGHT OR LEFT).
IV. "SERVE VENT AND SPONGE!"
V. "LOAD!"
VI. "ELEVATE!"
VII. "PRIME!"
VIII. "READY--FIRE!"
IX. "MORTAR FRONT!"
X. "SECURE!"

The exercise commences with the supposition that the Mortar is secured fore and aft, but not loaded.

I. "SILENCE!"

(Diagram 1.)

447. At this preparatory order the strictest silence is to be observed.

The Captain faces the breech, the men on the right and left stand facing the mortar; all fix their eyes on the Captain, and attentively wait for orders.

II. "CAST LOOSE AND PROVIDE!"

(Diagram 2.)

448. 1st Captain commands; sees his mortar cleared and cast loose; canvas covers taken off; Eccentric Bars in their place; Train-Tackles overhauled and placed fore and aft on deck; Shell-whip hooked into mast-head span; small shell-hooks moused on lower block of shell-whip; Shell-tongs ready for use; Grommet for resting shell on deck at hand; basket of implements on deck to the rear of mortar; Tompion taken out and placed to the rear; sees that there is a Gunner's Quadrant and plumb-line in the basket; a boring-bit between beckets; a breeching and tackle, if it should be wanted; buckles on his waist-belt, furnished with a primer-box; equips himself with a priming-wire and lanyard; places elevating lever on the right side of mortar ready for use.

2d Captain gets basket of implements and spirit-level from the Gunner; places basket on deck to the rear of the mortar; screws spirit-level to trunnion, and adjusts it to an angle of 45 deg. with the axis of the bore.

No. 3, First Loader, removes mortar-cover; takes out tompion and places it to the rear of mortar-circle, out of the way; provides grommet for resting shell on deck; gets scrapers and spatulas out of basket.

No. 4, First Sponger, assists in removing mortar-cover; gets his sleeves out of basket and puts them on; provides an empty cartridge-bag for wiping shell.

Nos. 5 and 6, Second Loader and Second Sponger, hook shell-whip into mast-head span, and bring it perpendicular over the bore; mouse small shell-hooks on to lower block; get breechings and tackles ready for hooking; ship front eccentric bars.

Nos. 7 and 8, Shell-carriers, get shell-tongs for carrying shell; assist in shipping eccentric bars on their respective sides of circle.

Nos. 9 and 11 overhaul left train-tackle to its full length, and place it on deck fore and aft, near the ship's side; ship left circle eccentric bar, and place lever for carriage-eccentric on the circle, butt to the front, and close to the side of carriage.

Nos. 10 and 12 execute the same duties on the right side of the mortar.

Nos. 11 and 12 also ship rear eccentrics.

Nos. 9, 10, 11, 12, hook tackles for hoisting shell from below.

No. 13, Powder-man, repairs to the proper scuttle for his passing-box, returns, and stands a little to the left and in rear of the circle.

III. "TRAIN!" (RIGHT OR LEFT).

(Diagram 3.)

449. Nos. 5, 6, 7, 8, 9, 10, 11, and 12, throw circle eccentric into gear, and pin eccentric bars down. Nos. 5 and 6 then hook double blocks of train-tackles into circle on their respective sides. All the crew, except Nos. 1 and 2, will bowse on train-tackles, until the mortar is in the desired direction, when the order "Well!" will be given by No. 2, who attends spirit-level and trunnion-sight.

At the command "Well!" Nos. 5 and 6, 11 and 12 will unhook their respective blocks and lay the train-tackle fore and aft on deck, near the ship's side; Nos. 5 and 6, 7 and 9, 8 and 10, 11 and 12, throw the circle eccentrics out of gear.

IV. "SERVE VENT AND SPONGE!"

450. 1st Captain inserts his priming-wire and clears the vent. No. 3 scrapes the chamber and bore, removes scrapings with the spoon. No. 4 takes the empty cartridge-bag and wipes out the mortar, then uses the sponge to thoroughly cleanse the chamber and bore; as soon as this operation is performed, the Captain again serves the vent. Should there be any fire or dirt pushed down, the sponging will be repeated.

D. Van Nostrand Publisher. Julius Bien, pr.]

D. Van Nostrand Publisher. Julius Bien, pr.]

V. "LOAD!"

451. The Powder-man, No. 13, goes to the scuttle for a cartridge, and brings it to No. 3 (always passing on the side not engaged), who empties it carefully into the chamber, keeping the cartridge-bag in his hand, to be used in wiping the shell before it is lowered into the bore. No. 4 takes spatulas, levels off the powder, and calls out "Shell!" which is brought to the front of the mortar by Nos. 7 and 8, Shell-carriers, and landed in the grommet, which has been put in its proper place by No. 5. Nos. 5 and 6 hook shell on and whip it up; when high enough, No. 3 calls out, "High!" wipes it clean with empty cartridge-bag, and, assisted by No. 4, steadies it over the bore; it is then lowered carefully upon the charge, keeping the fuze exactly in the axis of the bore. No. 4 then removes the paper covering and exposes the priming of the fuze, handing the covering to No. 2, as an evidence that it has been removed. After an exercise or an action, these paper coverings will be compared with the account kept by the Officer having charge of the Powder Division. Nos. 3 and 4 now step down on deck, ready to assist in training, should any be required.

VI. "ELEVATE!"

452. The 2d Captain, having adjusted the trunnion-sight[44] to a given angle with the axis of the bore (usually 45 deg.), orders "Raise" or "Lower;" and at the same time the 1st Captain inserts the elevating lever through elevating loop, on to ratchet, and raises or lowers according to direction from 2d Captain, who will give the word "Well!" when the mortar has its proper elevation.

VII. "PRIME!"

453. 1st Captain inserts his priming-wire to ascertain that the vent is clear; takes a friction-primer, raises the loop nearly in line with the spur, hooks it on his lanyard and inserts the primer into the vent, being careful that the lanyard has been led through the loop at the rear of mortar-carriage for that purpose; then retires to the rear of mortar to the full length of the lanyard, and gives the word.

Officer in charge takes station to watch the effect of the bomb, which shall be recorded in a suitably ruled note-book.

VIII. "READY--FIRE!"

454. At the word "Fire!" the Captain pulls the lanyard with a quick draw: there should be a pause of about two seconds between the words "Ready" and "Fire," in order to allow every one time to retire to the rear.[45]

IX. "MORTAR--FRONT!"

455. Nos. 1 and 5, on the left side, Nos. 2 and 6, on the right side, step on the circle; take carriage eccentric levers and throw eccentrics into gear; withdraw the lever from the sockets, and insert them into holes in the wheel, and heave the mortar-carriage up against the front hurter; throw eccentric out of gear; place levers on the circle close to Brackets, butts forward, and retire to their stations.

X. "SECURE!"

(Diagram 1.)

456. Train fore and aft, face of mortar forward, throw circle out of gear; 1st Captain stops vent; 2d Captain unscrews spirit-level. Nos. 3 and 4 put in tompion, put on mortar-cover, put scrapers, spoons, sleeves, and empty cartridge-bags into basket. Nos. 5 and 6 unhook shell-whip and coil it up on the lower step of carriage; put small shell-hooks into basket; put grommet between brackets of carriage; coil up breeching-tackle, and put it on the lower step of carriage; secure the mast-head span to the rigging; unship front circle eccentric. Nos. 7 and 9 coil left train-tackle on the circle, left side of carriage, unship left circle eccentric bar. Nos. 8 and 10 coil right train-tackle on the circle, right side of carriage, unship right circle eccentric bar. Nos. 11 and 12 coil shell-tackle on the circle in rear of carriage; unship rear circle eccentric bar. Eccentric bars to be placed on the circle in the following manner: left and front bars, on left side of brackets; right and rear bars on the right side of brackets. Nos. 7 and 8 put shell-tongs on circle to the rear of carriage. 1st Captain puts his lanyard and priming-wire into the basket, which, together with the spirit-level, is carried to the Gunner by 2d Captain; the crew then resume their stations as at "SILENCE."

MAGAZINE AND SHELL-ROOM.

457. Vessels specially constructed for mortar purposes have regularly-built shell-rooms, while others, fitted for temporary service, have merely spaces set apart, which should be protected by screens fitting tightly to the beams and deck, with tubs of water always at hand during practice, and likewise wet swabs laid to cut off trains of powder.

458. Before the vessels leave port, every thing must be arranged in the magazines for the rapid and safe transmission of ammunition to the mortars, and any deficiencies should be promptly reported to the Officer commanding the division, and by him to the Officer in charge of ordnance.

459. The Officer in command of each vessel is to be present at the embarkation of the ordnance, to stow and check the lists.

460. All the implements accompanying the mortars are to be kept in lockers used solely for that purpose, and under the charge of the Gunner or his mate.

461. The full service-charges for the mortars will be sent on board ready filled in white cotton bags, and their transmission from the magazines will be in leather passing-boxes.

462. The powder is to be emptied into the mortar, the bag well shaken and beaten over the lee-side to remove dust and fine grains of powder, and the bag placed in the rear to wipe out the mortar-chamber after every round.

None of these bags should be returned to the magazine during the action, as the loose powder would be likely to form trains.

463. Large tubs of water are to be kept near the magazines, with buckets at hand to drown the cartridges, or to extinguish fire; and every precaution taken to cut off trains of powder with wet swabs.

464. The forward part of the vessel above decks will be used as the most convenient place for cutting or preparing fuzes, and a heavy screen, spread tent-fashion, should be rigged to protect the fuzes from fire from the mortars, or rain.

In filling shells, the Gunner and two assistants will be detailed for this purpose, besides the men stationed to pass powder from the magazines.

All fire and lights must be put out when the magazine is opened for action.

465. In firing against the wind, the flame is thrown back in-board; therefore care should be taken beforehand to wet the sides, decks, and rigging of the vessel; the sails covered with tarpaulins; and men stationed with buckets to put out fire.

466. One hundred bombs are at all times to be kept ready filled in the shell-room.

A vessel properly organized ought to throw at least 20 bombs an hour; but should circumstances prevent, the mortar may be properly served if even one bomb can be filled before the previous one is fired.

467. A beech plug must be temporarily put in the fuze-hole of the bomb when filled; and the men who fill cartridges and charge the bombs are to wear flannel sleeves and magazine-shoes.

468. When ranges are desired to be obtained by reduced charges, the measuring and filling of the cartridges must always be done in the magazine, no matter how inconvenient it may be; and the utmost exactness is to be observed in filling the powder-measures and levelling off the top, as an ounce of powder makes an important variation in the range of the bomb.

469. Extra cotton bags are to be provided to receive the reduced charges, which are to be stowed in half barrels.

470. Every precaution that suggests itself to the officers in command to prevent accidents, should immediately be put in force, and a memorandum of the matter transmitted to the Ordnance Officer of the squadron.

GENERAL RULES AND OBSERVATIONS.

471. To estimate the distance by the bursting of a bomb, where the flash can be seen, multiply the number of seconds which elapse between it and the sound of the report by 1,100, and the product will be nearly the distance in feet.

472. The officer in charge of a mortar must always note the time of flight and distance, by the above rule, for every bomb that is fired, and likewise note when the report is not heard from the bursting charge.

473. When going into action for a bombardment, the fore-rigging must be come up on the side where the mortar is to be used, the fore-topmast sent down, foresail unbent, boom and gaff laid on deck, rigging lashed in close to the mast, head-sails to be thoroughly wetted, spring on the cable, boats lowered from the side davits, and all the hatches covered with tarpaulins.

474. The broadside-guns must be kept ready for action, and muskets loaded and at hand, in case the squadron should be attacked by the enemy's gunboats.

475. Besides bombs, various other projectiles are fired from mortars, such as carcasses, which are shells having three holes of similar dimensions to the fuze-hole, pierced at equal distances apart in the upper hemisphere, with their exterior openings touching the great circle which is perpendicular to the axis of the bore.

476. These carcasses are placed in the mortar in the same manner as the bomb, and are filled with inflammable mixtures, and should be transported in a vessel by themselves, as they are dangerous companions. Thirteen-inch carcasses weigh 194 pounds each.

477. Bombs are sometimes fired with a port fire stuck into the fuze-hole, which is an almost certain mode of igniting many kinds of buildings.

478. Mortars can also be fired with a bag of one-pound balls, or ordinary grape-shot, with very reduced charges, and a wad between the powder and the balls. One pound of powder will project a 200-lb. bomb 302 yards; the same weight of grape-shot thrown in among boats would prove destructive; and especially a lot of canister fired in this manner would cause great havoc.

479. It is not expected, however, that much execution could be done after the first discharge in a fleet of boats moving rapidly; but combined with the batteries of the Squadron, it is presumed that an enemy would be deterred from an attempt to capture a vessel by boarding.

TAKING THE DISTANCE.

480. An inexperienced officer will find difficulty in estimating distances by the eye alone, as it requires long practice and studied observation. The sextant, however, offers a surer method of approximately fixing a position by taking the angles between any three points, which are generally found to be accurately laid down on the Coast Survey charts; then plotting the angles with a horn protractor, or working them out by the three-point problem, which is given in all surveying books.

481. If the object to be assaulted is a large one, a practical man can, by the exercise of moderate judgment after two or three fires, throw the bombs near the work; but, at the same time, the sextant is the more certain means for determining the true distance, and the Officer in command should make himself acquainted with the simple manner of measuring horizontal angles.

482. If points are not visible in line, then measure a base on shore, angle on the object to be aimed at, and from the angles of the base-line, you can fix the position of the mortar-vessel.

483. When a vessel once gets her position accurately determined, and it becomes necessary after a bombardment to remove out of the line of battle, a small buoy with the vessel's name or number should be dropped under foot, so that the same position may, if necessary, be resumed.

LOADING MORTARS.

484. After the powder has been emptied through the funnel out of the cotton bag into the chamber, the bomb, loaded and fuzed, is to be carefully lowered into the bore by the hooks, and allowed to rest upon the charge.

485. The friction-tube is not put into the vent until the piece is about to be fired.

FUZES.

486. The wooden fuzes used at present for the 13-inch bombs are in sections, and marked according to the estimated distance in practice, viz.:

Seven inches extreme length; and each section one inch, giving a flight for every section of seven seconds, and a total of forty-nine seconds.

487. The plugs are of the proper size for the fuze-hole; the axis bored cylindrically from the large end down, to within a short distance of the small end, which is left solid; the orifice is filled with composition pressed hard and evenly as possible. At the large end a cup is hollowed out and filled with mealed powder moistened with alcohol.

488. The rate of burning is ascertained by experiment, and marked on a water-proof cap, which is tied over the cup.

489. A fuze-saw must be at hand during practice to cut the fuze the required length.

490. Fuzes for sea-coast mortars are also driven in a conical paper case, which is inserted in a metal or wooden plug previously driven in the fuze-hole and accurately reamed out.

491. The paper-case fuze is marked with the number of seconds it burns per inch, and it may be cut, where no danger from ignition can take place, with a sharp knife.

PROCESS OF FILLING BOMBS.

492. Having been inspected to see that they are clean and dry, place the bombs on a block made for the purpose, or on grommets of rope, or on the ground, with the eyes up. The charge, having been carefully measured, is then poured into the chamber through a funnel, while, at the same time, the fuze is cut to the proper length by resting it on a groove made in the block, and sawing it across. The fuze is then tried in the hole, and should enter 3/4ths of its length; if it does not, it must be reduced by rasping.

493. The head of the fuze having been covered with tow to prevent breaking the composition, the fuze-setter is placed on it, and the fuze driven with the mallet until the head is about 2/10ths of an inch above the surface of the bomb.

POINTING MORTARS.

494. First give the elevation by applying the quadrant to the face of the piece, and adjusting the quoin or ratchet until the required number of degrees is obtained.

495. In pointing mortars on shore, it is an easy matter to get the direction, because the mortar is stationary; but on shipboard, owing to the motion, it is attended with difficulty, especially when the vessel is rolling and the line of fire can only be approximate.

496. On shore, the plan of giving the direction is to determine practically two fixed points, which shall be in a line with the piece and the object, and sufficiently near to be readily distinguished by the eye. These points being covered by a plummet, is the vertical plane including the line of metal, which becomes the plane of fire.

497. In mortar-vessels other expedients are resorted to, such as trunnion-sights, or a white line painted on the mortar-bed parallel to the axis of the bore when level; but the first plan is preferable.

498. The circles on which the mortars stand being fitted with eccentrics, are made to revolve so as to point the mortar at the object without the trouble of swinging the vessel or moving the mortar round with handspikes.

499. Before firing, care must be taken that the eccentrics are thrown out of gear, and the circle flat upon the platform on which it revolves.

TABLES OF CHARGES, ELEVATIONS, AND RANGES FOR 13-INCH MORTARS.

500. CHARGES FOR 13-INCH MORTAR-BOMBS.

---------------------------------------------+-------------+ Charge. | 13-Inch. | ---------------------------------------------+-------------+ | lbs. oz. | Of shell filled | 11 0 | To burst shell | 6 0 | To blow out fuze | 0 6 | Ordinary service-charge | 7 0 | Incendiary, match, or other composition | 0 8 | ---------------------------------------------+-------------+

501. RANGES WITH SEA-COAST 13-INCH MORTARS, 20 deg. ELEVATION.

-----------------------------------------------------------+
Charge. | Mean Time of | Least | Greatest | Mean |
| Flight. | Range. | Range. | Range. |
---------+--------------+------------+----------+----------+
Lbs. | Seconds. | Yards. | Yards. | Yards. |
4 | 8. | 840 | 877 | 869 |
6 | 9.5 | 1209 | 1317 | 1263 |
8 | 11.66 | 1653 | 1840 | 1744 |
10 | 12.50 | 2010 | 2128 | 2066 |
12 | 14.25 | 2369 | 2688 | 2528 |
14 | 15.25 | 2664 | 2780 | 2722 |
---------+--------------+------------+----------+----------+

502. RANGES WITH 13-INCH MORTARS, AT 45 deg. ELEVATION.

Weight of Shell, 200 lbs.

+----------+----------+-----------------+--------+ | CHARGE. | FLIGHT. | FUZE. | RANGE. | +----------+----------+-----------------+--------+ | Lbs. oz. | Seconds. | Inches. 10ths. | Yards. | | 7 | 21.4 | 4 2-2/3 | 2190 | | 7 8 | 22.4 | 4 4 | 2346 | | 8 | 23.2 | 4 6 | 2480 | | 8 8 | 23.8 | 4 7-1/2 | 2600 | | 9 | 24.4 | 4 8-3/4 | 2734 | | 9 8 | 24.9 | 4 9-3/4 | 2853 | | 10 | 25.4 | 5 1 | 2958 | | 10 8 | 25.9 | 5 1-3/4 | 3026 | | 11 | 26.3 | 5 2-1/2 | 3150 | | 11 8 | 26.7 | 5 3-1/2 | 3246 | | 12 | 27.0 | 5 4 | 3327 | | 12 8 | 27.4 | 5 4-3/4 | 3404 | | 13 | 27.7 | 5 5-1/2 | 3470 | | 13 8 | 28.0 | 5 6 | 3552 | | 14 | 28.3 | 5 6-1/2 | 3617 | | 14 8 | 28.5 | 5 7 | 3681 | | 15 | 29.0 | 5 8 | 3739 | | 15 8 | 29.1 | 5 8-1/4 | 3797 | | 16 | 29.2 | 5 8-1/2 | 3849 | | 16 8 | 29.4 | 5 8-3/4 | 3901 | | 17 | 29.6 | 5 9 | 3949 | | 17 8 | 29.8 | 5 9-1/2 | 3997 | | 18 | 29.8 | 5 9-3/4 | 4040 | | 18 8 | 30.0 | 6 | 4085 | | 19 | 30.2 | 6 0-1/4 | 4123 | | 19 8 | 30.3 | 6 0-1/2 | 4160 | | 20 | 30.5 | 6 1 | 4200 | +----------+----------+-----------------+--------+

503. TABLE OF ALLOWANCES.

Subjoined is a list of articles which are indispensable for the service required, and must be kept in readiness at or near every mortar, in some secure position:

Tube-boxes 4
Straps for boxes 4
Quill-tubes 400
Friction-tubes 600
Fuze-composition for priming 12 lbs.
Powder-bags 250
Port-fires 100
Port fire-sticks 4
Rasps, half round 4
Cotton wick 4 lbs.
Hand-hatchets 2
Sheep-skins 6
Diagonal scale 1
Compasses 2
Copper funnel, 13 in. 1
Wood mallets 2
Fuze-extractor 1
Iron pincers 2
Augurs 2
Cutting-knives 2
Scissors 2
Thread 1 lb.
Brass quadrants 1
Sponges with staves, 13 in. 2
Handspikes 6
Claw-hammers 1
Lead plummets 3
Tallow 20 lbs.
Shell-hooks, 13 in. 2
Shell-hooks, with thimbles 2
Cotton quick-match 6
Punches for mortar-vents 2
Corkscrews 2
Blocks for driving fuzes 2
Drifts of iron tapped with copper 4
Copper ladles for fuzes 2
Leather buckets 3
Elm plugs 60
Brass pickers 2

SPARE ARTICLES.

Cap-squares
Eye-pins
Keys for pintles, large 2
Keys for pintles, small 2
Washers 2
Bolts, traversing 4
Bolts, dog 4

FOOTNOTES:

[44] If the Spirit-Level should be damaged, he will apply the Gunner's Quadrant to the face of the mortar.

[45] To lessen the shock of the discharge and the concussion on the ear, the crew should be instructed to stand on their toes at the moment of firing, keeping at the same time their mouths and ears open.