Mr C Patrick Hreachmack
Report on Iron Clad Vessels
Navy Department - Bureau of Yards and Docks, September 16, 1861
The undersigned, constituting a board appointed by your order of the 8th ultimo, proceeded to the duty assigned to them, in accordance with the first section of an act of Congress, approved 3d of August 1861, directing the Secretary of the Navy "to appoint a board of three skillful naval officers to investigate the plans and specifications that may be submitted for the construction or completing of iron-clad steamships or steam batteries to be built; and there is hereby appropriated, out of any money in the treasury not otherwise appropriated, the sum of one million five hundred thousand dollars."
Distrustful of our ability to discharge this duty, which the law requires should be performed by three skillful naval officers, we approach the subject with diffidence, having no experience and but scanty knowledge in this branch of naval architecture.
Application was made to the department for a naval constructor, to be placed under our orders, with whom we might consult; but it appears that they are all so employed on The construction of iron-clad steamships of war is now zealously claiming the attention of foreign naval powers. France led off; England followed, and is now somewhat extensively engaged in the system; and other powers seem to emulate their example, though on a smaller scale.
Opinions differ amongst naval and scientific men as to the policy of adopting iron armature for ships-of-war. For coast and harbor defense they are undoubtedly formidable adjuncts to fortifications on land. As cruising vessels, however, we are sceptical as to their advantages and ultimate adoption. But whilst other nations are endeavoring to perfect them, we must not remain idle.
The enormous load of iron, as so much additional weight to the vessel; the great breadth of beam necessary to give her stability; the short supply of coal she will be able to stow in bunkers; the greater power required to propel her and the largely increased cost of construction, are objections to this class of vessels as cruisers which we believe it is difficult successfully to overcome. For river and harbor service we consider iron-clad vessels of light draught, or floating batteries thus shielded as very important; and we feel at this moment the necessity of them on some or our rivers and inlets to enforce obedience to the laws. We, however, do not hesitate to express the opinion, notwithstanding all we have heard or seen written on the subject, that no ship or floating battery, however heavily she may be plated, can cope successfully with a properly constructed fortification of masonry. The one is fixed and immovable, and though constructed of a material which may be battered by shot, can be covered, if need be, by the same or much heavier armor than a floating vessel can bear, whilst the other is subject to disturbances by winds and waves, and to the powerful effects of tides and currents.
Armored ships or batteries may be employed advantageously to pass fortifications on land for ulterior objects of attack, or run a blockade, or to reduce temporary batteries on the shores of rivers and the approaches to our harbors.
From what we know of the comparative advantages and disadvantages of ships constructed of wood over those of iron, we are clearly of opinion that no iron-clad vessel of equal displacement can be made to obtain the same speed as one not thus encumbered, because her form would be better adapted to speed. Her form and dimensions, the unyielding nature of the shield, detract materially in a heavy sea from the life, buoyancy, and spring which a ship built of wood possesses.
Wooden ships may be said to be but coffins for their crews when brought in conflict with iron-clad vessels; but the speed of the former, we take for granted, being greater than that of the latter, they can readily choose their position, and keep out of harm's way entirely.
Recent improvements in the form and preparation of projectiles, and their increased capacity for destruction, have elicited a large amount of ingenuity and skill to devise means for resisting them in their construction of ships-of-war. As yet we know of nothing superior to the large and heavy spherical shot in its destructive effects on vessels, whether plated or not.
Rifled guns have greater range, but the conical shot does not produce the crushing effect of spherical shot.
It is assumed that 4 inch plates are the heaviest armor a sea going vessel can safely carry. These plates should be of tough iron, and rolled in large long pieces. This thickness of armor, it is believed, will resist all projectiles now in general use at a distance of 500 yards, especially if the ship's sides are angular.
Plates hammered in large masses are less fibrous and tough than when rolled. The question whether wooden backing, or any elastic substance behind the iron plating will tend to relieve at all the frame of the ships from the crushing effect of a heavy projectile, is not yet decided. Major Barnard says "to put an elastic material behind iron is to insure its destruction." With all difference to such elastic substance (soft wood, perhaps, is best) might relieve the frame of the ship somewhat from the terrible shock of a heavy projectile, though the plate should be fractured.
With respect to a comparison between ships of iron and those of wood, without plating, high authorities in England differ as to which is best. The tops of ships built of iron, we are told, wear out three bottoms; whilst the bottoms of those built of wood will outwear three tops. In deciding upon the relative merits of iron and wooden-framed vessels, for each of which we have offers, the board is of opinion that it would be well to try a specimen of each as both have distinguished advocates. One strong objection to iron vessels which, so far as we know, has not yet been overcome, is the oxidation or rust in salt water, and their liability of becoming foul under water by the attachment of sea grass and animalcules to their bottoms. The best preventative we know of is a coating of pure zinc paint, which, so long as it lasts, is believed to be an antidote to this cause of evil.
After these brief remarks on the subject generally, we proceed to notice the plans and offers referred to us for construction of plated vessels and floating batteries.
It has long been suggested that the most ready mode of obtaining an iron-clad ship-of-war would be to contract with responsible parties in England for its complete construction; and we are assured that parties there are ready to engage in such an enterprise on terms more reasonable, perhaps, than such a vessels could be built in this country, having greater experience and facilities than we possess. Indeed, we are informed there are no mills and machinery in this country capable of rolling iron 4 inches thick, though plates might be hammered to that thickness in many of our workshops. As before observed, rolled iron is considered much the best, and the difficulty of rolling it increases rapidly with the increase of thickness. It has, however, occurred to us that a difficulty might arise with the British government, in case we should undertake to construct ships-of-war in that country, which might complicate their delivery; and moreover, we are of opinion that every people or nation who can maintain a navy should be capable of constructing it themselves.
Our immediate demands seem to require, first, so far as practicable, vessels invulnerable to shot, of light draught of water, to penetrate our shoal harbors, rivers and bayous. We, therefore, favor the construction of this class of vessels before going into a more perfect system of large iron-clad sea-going vessels of war. We are here met with the difficulty of encumbering small vessels with armor, which, from their size, they are unable to bear. We, nevertheless, recommend that contracts be made with responsible parties for the construction of one or more iron-clad vessels or batteries of as light a draught of water as practicable consistent with their weight of armor. Meanwhile, availing of the experience thus obtained, and the improvements which we believe are yet to be made by other naval powers in building iron-clad ships, we would advise the construction, in our own dock-yards, of one or more of these vessels upon a large and more perfect scale, when Congress shall see fit to authorize it. The amount now appropriated is not sufficient to build both classes of vessels to any great extent.
We have made a synopsis of the propositions and specifications submitted, which we annex, and now proceed to state, in brief, the results of our decisions upon the offers presented to us.
J. Ericsson, New York, page 19 - This plan of a floating battery is novel, but seems to be based upon a plan which will render the battery shot and shell proof. We are somewhat apprehensive that her properties for sea are not such as a sea-going vessel should possess. But she may be moved from one place to another on the coast in smooth weather. We recommend that an experiment be made with one battery of this description on the terms proposed, with a guarantee and forfeiture in case of failure in any of the properties and points of the vessel as proposed.
Price, $275,000; length of vessel, 172 feet; breadth of beam, 41 feet; depth of hold, 11 feet; time, 100 days; draught of water, 10 feet; displacement 1,255 tons; speed per hour, nine statute miles.
John W. Nystrom, Philadelphia, 1216 Chestnut Street, page 1 - The plan of (quadruple) guns is not known, and cannot be considered. The dimensions would not float the vessel without guards, which we are not satisfied would repel shot. We do not recommend this plan.
Price, about $175,000; length of vessel, 175 feet; breadth of beam, 27 feet; depth of hold, 13 feet; time, four months; draught of water, 10 feet; displacement, 875 tons; speed per hour, 12 knots.
William Perine, New York, 2777 post office box, presents three plans. The specifications and drawings are not full. The last proposal (No. 3, page 2) for the heavy plating is the only one we have considered; but there is neither drawing nor model, and the capacity of the vessel, we think, will not bear the armor and armament proposed.
Price, $621,000; length of vessel, 225 feet; breadth of beam, 45 feet; depth of hold, 15 feet; time, 9 months, draught of water, 13 feet; displacement, 2,454 tons; speed per hour, 10 knots.
John C. Ferre, Boston, page 9 - Description deficient. Not recommended. Sent a model, but neither price, time, nor dimensions stated.
E. S. Renwick, New York, 335 Broadway, presents drawings, specification, and model of an iron-clad vessel of large capacity and powerful engines, with great speed, capable of carrying a heavy battery, and stated to be shotproof and a good sea-boat. The form and manner of construction and proportions of this vessel are novel, and will attract the attention of scientific and practical men. She is of very light draught of water, and on the question whether she will prove to be a safe and convertible sea-boat we do not express a decided opinion. Vessels of somewhat similar form, in that part of vessel which is immersed, of light draught of water on our western lakes, have, we believe, proved entirely satisfactory in all weathers. To contract the effect of waves, when disturbed by the winds, by producing a jerk, or sudden rolling motion of flat, shoal vessels, it is proposed to carry a sufficient weight above the center of gravity to counterpoise the heavy weight below, which is done in this ship by the immense iron armor. If, after a full discussion and examination by experts on this plan, it should be decided that she is a safe vessel for sea service, we would recommend the construction upon it of one ship at one of our dock yards.
The estimate cost of this ship, $1,500,000, precludes action upon the plan until further appropriations shall be made by Congress for such objects.
Time not stated; length of vessel, 400 feet; breadth of beam 60 feet; depth of hold, 33 feet; draught of water, 16 feet; displacement, 6,520 tons; speed per hour, at least 18 miles.
Whitney & Rowland, Brooklyn, Greenpoint, page 13, propose an iron gunboat, armor of bars of iron and thin plate over it. No price stated. Dimensions of vessel, we think, will not bear the weight and possess stability. Time, 5 months. Not recommended.
Length of vessel, 140 feet; breadth of beam, 28 feet; depth of hold, 13 feet; draught of water, 8 feet.
Donald McKay, Boston, page 16 - Vessel, in general dimensions and armor, approved. The speed estimated slow. The cost precludes the consideration of construction by the board.
Price, k$1,000,000; length of vessel, 227 feet; breadth of beam, 50 feet; depth of hold, 26 feet; time, 9 to 10 months; draught of water, 13 feet; displacement, 1,215 tons; speed, not stated.
William H. Wood, Jersey City, N.J., page 14 - Dimensions will not float the guns high enough; not recommended.
Price, $225,000; length of vessel, 160 feet; breadth, 34 feet; depth of hold, 22 feet; time, 4 months; draught of water, 13 feet; displacement, 1,215 tons; speed, not stated.
Merrick and Sons, Philadelphia, pages 7 and 8. - Vessel of wood and iron combined. This proposition we consider the most practicable one for heavy armor. We recommend that a contract be made with that party, under the guarantee, with forfeiture in case of failure to comply with specifications; and that the contract require the plates to be 15 feet long and 36 inches wide, with a reservation of some modifications, which may occur as the work progresses, not to affect the cost.
Price, $225,000; length of vessel, 220 feet; breadth of beam, 60 feet; depth of hold 23 feet; time, 9 months; draught of water, 13 feet; displacement, 3,296 tons; speed per hour, 9 knots.
Benjamin Rathburn,_____________, page 20. We do not recommend the plan for adoption.
Price not stated; length of vessel not stated; breadth of beam, 80 feet; depth of hold, 74 feet; time not stated; draught of water, 25 feet; displacement, 15,000 tons; speed not stated. Specifications incomplete.
Henry R. Dunham, New York, page 11. - Vessel too costly for the appropriation; no drawings or specifications; not recommended.
Price, $1,200,000; length of vessel, 325 feet; breadth of beam 60 feet; depth of hold not stated; time, 15 to 18 months; draught of water, 16 feet; displacement not stated; speed per hour, 12 miles.
C.S. Bushnell, & Co., New Haven, Conn., page 121, propose a vessel to be iron-clad, on the rail and plate principal, and to obtain high speed. The objection to this vessel is the fear that she will not float her armor and load sufficiently high, and have stability enough for a sea vessel. With a guarantee that she shall do these, we recommend on that basis a contract.
Price, $235,250; length of vessel, 180 feet; breadth of beam,_____feet; depth of hold, 12 2/3 feet; time, 4 months; draught of water, 10 feet; displacement,________tons; speed per hour, 12 knots.
John Westwood, Cincinnati, Ohio, page 17. - Vessel of wood, with iron armor; plan good enough, but the breath not enough to bear armor. No detailed specification; no price or time stated; only a general drawing. Not recommended.
Neafie & Levy, Philadelphia, page 5. - No plans or drawings, therefore not considered. Neither price nor time stated. Length of vessel, 200 feet; breadth of beam, 40 feet; depth of hold, 15 feet; draught of water, 13 feet; displacement, 1,748 tons; speed per hour, 10 knots.
Wm. Norris, New York, 26 Cedar Street, page 6. - Iron boat without armor. Too small, and not received.
Price, $32,000; length of vessel, 83 feet; breadth of beam, 25 feet; depth of hold, 14 feet; time, 60 to 75 days; draught of water, 3 feet; displacement, 90 tons; speed not stated.
Wm. Kingsley, Washington, D.C., page 10. - proposes a rubber-clad vessel, which we cannot recommend. No price or dimension stated.
A. Beebe, New York, 82 Broadway, page 18. - Specification and sketch defective. Plan not approved.
Price, $50,000; length of vessel, 120 feet; breadth of beam, 55 feet; depth not stated; time, 100 days; draught of water, 6 feet; displacement, 1,000 tons; speed per hour, 8 knots.
These three propositions recommended, viz: Bushnell & Co., New Haven, Connecticut; Merrick & Sons, Philadelphia; and J. Ericsson, New York, will absorb $1,290,250 of the appropriation of $1,500,00, leaving $209,750 yet unexpended.
The board recommends that armor with heavy guns be placed on one of our river craft, or, if none will bear it, to construct a scow, which will answer to plate and shield the guns, for the river service on the Potomac, to be constructed or prepared by the government at the navy yard here for immediate use.
We would further recommend that the department ask of Congress, at its next session, an appropriation, for experimenting on iron plates of different kinds, of $10,000.
All of which is respectfully submitted.
I. H. DAVIS
Hon. Gideon Welles,
Secretary of the Navy Ironsides
Mr C Patrick Hreachmack
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