US2791980A - Hull form and construction for metal vessels - Google Patents

Description

May 14, 1957 HULL FORM AND CONSTRUCTION FOR METAL. VESSELS Filed March 30, 1953 c. M. BEST, JR 2,791,980

3 Sheets-Sheet l N N m i INVENTOR.

COE MjBEST JR.

MaDEwJQ/L A TTO 2 N576- May 14, 1957 c. M. BEST, JR 2,791,980

HULL FORM AND CONSTRUCTION FOR METAL VESSELS Filed March 50, 1953 3 Sheets-Sheet 2 I INVENTOR. CO5 M. 555 7 1W.

y 14, 1957 c. M. BEST, JR 2,791,980

HULL FORM AND CONSTRUCTION FOR METAL VESSELS Filed March 30, 1953 3 Sheets-Sheet 3 INVENTOR. COE N. 855 T JR.

YJL'MZWZ United States Patent HULL FORM AND CONSTRUCTION FOR- METAL VESSELS- Coe M. Best, Jr.,.New Orleans, La.

Application. March 30', 1953, Serial No. 345,329

6 Claims. (Cl. 114-56) My present invention. relates to a hull' form and construction for metal vessels.v More particularly, my invention relatesto a new improved hull form and construction which provides a blunt deck. plan with seaworthy underbody form. characteristics, permitting operation in open rough waters as well as in rivers, harbors,, and' other relatively calm areas of water. Such vessels are generally constructed of steel and include barges, towboats, tugs, movable drydocks, landing craft, military amphibious vessels, and other types of. Water supported vessels.

Barges and towboats in common use today, operate mainly in rivers and harbors but are, not capable of car'- rying loads upon the sea or other open waters. This is trueprimarily because the hull design heretofore employed consisted of a main load bearing middle body having a similar bow and stern formed with upturned relatively blunt ends; This form has been used for many years and has been relatively satisfactory inoperations in calm waters. However,. even in such' waters many difiiculties' have. arisen with this conventional barge having a blunt bow. Thus,for example'in, operations in harbors and rivers in the winter'when encountering broken floating ice or anytime when floating debris is present such conventional barge will not tend-to cut a path of clear'water. Instead, such debris or ice tends either to remain at the bow of such vessel or to be forced back under the main portion of the hull' causing difiicult directional control over the barge, damage to the hull, and even at times causing damage toprope-llers or rudders requiring the cessation of movement until repairs can be made. Furthermore, even in relatively calm harbors and rivers there are periods ofdisturbed waters which make the operation of a barge having a blunt bow quite hazardous;

Thus, separately designed seaworthy vessels are required for work in open or relatively rough waters. Such seaworthy tugs have been designed with a conventional ship form bow or model'how, which isthe V-shap'edi bow commonly employed on many' passenger? and sporting-1 boats and ships. This V-shaped' bow tends to" cut' a path of clear waters forcing broken ice and debris to one" side thus preventing interruption duringithe-normal operation of't-he vessel and preventing possible damage to the hull thereof. The conventional ship form.- bowi'is used 'alsowhen a: vessel: is.designed to operate iniopen. or rougher waters since this cutting-or. parting action by-thati bow permits the. vessel-to: have relativelycontinuous. stable movement andadirec-tional-control:whemencountering waves or disturbedwaters This. form of vesselwhile adapted to open waterswhere the barges are towed behind a. tugboatisnot adapted to liver towing where thebarges are actually pushed in front of the towb'o'at; he'- oause the. sharp how does not have sufiicient transverse area to distribute. the pushing force required and cannot elficiently transmit the turning forces required for' directional' control of the barge tow, sometir'nesmore than lOOOfeetin length, ahead'of the towboat;

' The primary reason whyJthis/sharp or shipform how" has seldom beenemployed on barges limited to operation in calm Waters has been because of the greater expense involved in constructing such a bow as compared to the bow with upturned relatively blunt ends, and also the difficulty in incorporating the headlog or flat transverse plate used to transmit the pushing forces over them-ajor Width of the towboat. The term towboat in common usage on the Mississippi River system refers to a vessel which pushes a tow which is composed of one or more barges held together by rope making in effect one cargo carrying unit with power and. directional control supplied by the towboat. In order to. construct the shipform how the shell, or outer surface plates, must be formed in. two directions which is plastic deformation. This plastic deformation involves considerable efiort and expensesince'it requires that such plates must be heated andforged to the desired'shape or cut into small pieces and Welded to the shape, and, in fact, sometimes greater expense is involved if the shape is such that it requires the construction of forms or dies upon which to forge the plates. The necessity of plastic deformation of the plating'of the shipform bow is'readi'ly apparent when it is realized that the curvature of a conventional shipform bow is both-in the direction from the rniddlebody to the foremost point of the bow and further in the direction from the baseline of the hull to the Waterline.

However, the construction of the conventional barge having upturned relatively blunt ends does not require the'costly"operationof two directional forming, or plastic deformation, of the plates used in the construction of such abow. Forsuch barges these plates may be'formed inone direction'only. Thus; in fact, on a barge of this construction the bow plating is formed by a continuation of the bottom plating which has been bent or rolled in one direction only. Such deformation is referred to as elastic-deformation. This operation requires no heating of the plates, much less effort and is considerably less expensive than that involving plastic deformation.

I have found that a bow for steel vessels can be developed which possesses the many advantages of the aforementioned conventional ship form bow or model a bow and yet does not require the time consuming and expensive process of plastica'lly deforming the plating used to form the shell of such bow. Basically, the construction of thebow of my invention involves elastically deforming the. shell of the'bow section of the bull to coincide with. several conical surfaces; These conical surfaces are the partial surfaces of regular geometric cones. lt'isithe'initial location of these cones and moreparticularly the critical locati n of the apices of such cones that produces the improved bow of my invention.

Accordingly, it is an object of my invention to provide an all-around serviceh'eavy duty vessel which is capable of operating in. rougher waters and yet to develop a bow which does. not require the expensive process of plastically deforming the plates required in the bow.

It is a further object of my invention to provide a hull design for barges and towboat's having improved towing and strength characteristics and which may be more easily :and'econornically constructed.

Another object of my invention isto provide a barge with less shallow water resistance, greater strength, with more seaworthy characteristics, which may be economically constructed and may be maintained in operating condition at-less. cost.-v

Other objects and advantageswill become apparentasthe description proceeds.

To theaccomplishment of the foregoing and related ends, said invention, then, comprises the features hereinafter fully described and particularly pointed out in the-claims, the following description and the annexed drawings setting. forth indetail certain illustrative em- 3 bodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed.

A vessel illustrating the features of my invention is shown in the a nnexed drawings in which:

Fig. 1 is a plan view illustrating the development of my improved bow;

Fig. la is a front view of the bow illustrated in Fig. 1.

Fig. 1b is a side view.

Fig. 2 is a side view of a complete barge embodying my improved hull;

Fig 3 is a partial cut away perspective view illustrating the bottom development of my bow and possible framing to support the under-surface of the bow;

Fig. 4 is a perspective view of the completed bow; and

the framing of the bow. c

In designing a barge or towboat several main factors must be considered. The barge weight is composed of light ship weight, which includes all steel weight fittings and might be compared to the weight of an automobile with no fuel, oil or passengers anddead weight which in a barge is composed solely of cargo. To float this weight sufficient displacement is required and it is this factor which largely determines the overall size of the barge. Other factors such as lock widths and channel depths and other factors will however limit the beam or width and the draft of the barge. As illustrated in Fig. 2, load carrying barges generally consist of a central load carrying middlebody portion 7. This middlebody portion 7 is generally of constant or box section or economy in construction. Such middlebody terminates on each end with a cargo bulkhead generally indicated at 6. Beyond this cargo bulkhead or section 6 extends the bow and stern on their respectiveends of the load carrying middlebody. A

In determining the form of a hull it is necessary to establish an imaginary vertical plane extending from the center of the hull bottom up through the center of the vessel which is commonly referred to as the centerline of the hull. Referring to Fig. l, the centerline of the hull is indicated at 8-8. It is also necessary to establish an imaginary horizontal plane perpendicular to said centerline at the lowest point of the hull bottom which is commonly referred to as the baseline of the hull. Referring to Fig. 1a the baseline of the hull is indicated at 9-9.

The determination of the overall length of the hull from its furthest point forward to its furthest point aft along the centerline of the beam or width of the hull at its widest section, are factors to be initially determined in view of the service to which the hull is to .be subjected.

The rise in the lateral plating of the hull bottom from the intersection of the base line with the centerline to the intersection of the side plating with the bottom plating is generally referred to as the deadrisc and is provided to assist in the drainage of liquid cargos and for other purposes. The deadrise for the barge hull is generally indicated in Fig. l at 10.

Referring more particularly to Fig. 1, the development of the surface of my bow is dependent upon the location of several cones, the surface of which determine the shape of the bow. The lower section of the bow is formed by the partial surfaces of two cones, each such cone having its apex at A. The location of the apex is very critical in the development of these surfaces.

In Fig. 1, sections to 6 are illustrated. These sections are determined by commencing with the foremost point of the bow and arbitrarily establishing at that point an imaginary vertical plane perpendicular to both the centerline and the baseline as section 0 and further arbitrarily establishing a similar vertical plane section 6 at the point marking the end of the bow portion of the hull and indicating the cargo bulkhead of the Fig. is a plan view ofga metal plate used to cover load carrying middlebody 7 of the hull. The remaining sections 1-5 are accordingly assigned to equal portions between sections 0 and 6. Fig. 1 clearly illustrates the development of one-half of the bow of my invention. Point A must be located aft of section 6 externally of and spaced laterally of the hull proper and be in a plane embracing the middle bottom plating 12.

Point X is selected as any point above the waterline in section 0, on the center line 8-8 and being below the headpoint 13 of the bow so as to allow for an adequate headlog 14 for the bow.

Once point A has been established rays or generatrices af develop the surface of the cone which has its apex at point A. Ray 1 is initially established by a line between point A and point X. Ray a is established by a line connecting point A with the centerline of the hull which passes through point 15 which is the intersection of section 6 with a plane embracing the side plating"11"and a plane embracing the bottom plating 12 'of'fthe'hull; "Thus ray a is tangent to the bottom plating 12 of the hull. Once rays a and 1 have been established defining the uppermost and lower limits of that portion of the surface of the cone to be employed in the development of the bow, rays b to e are arbitrarily selected at equal intervals to fully establish the surface of the cone having its apex at A.

The convex conical surface established by rays a to f is in' fact a partial surface of a cone having its apex at A. This partial conical surface will extend in a gradual upward direction from the baseline of the hull bottom terminating in ray 1. Thus in effect the surfaceemployed in the development of this portion of the bow will utilize no more than about one-fourth of the total surface of the full cone having its apex at A.

The development illustrated in Fig. 1 shows only one- .half of the bow. A similar portion develops the other half so in effect the intersection of these two conical surfaces at the centerline 8-8 of the vessel establishes the full lower portion of the bow.

The development of the upper section of the bow is similarly drawn from the partial surfaces of the two partial cones. These latter cones each have as their apex point X which is located immediately below headlog 14 on the centerline 8--8 of the hull. The conical surfaces uses in this development are established by having one ray coinciding with ray f of the lower cone so that the conical surfaces of this development are tangent to the conical surfaces of the lower development along ray f. The additional rays g, h, i and k determine the conical surface of the upper surface of the bow and may arbitrarily be selected, the only limitation being the required allowance of a substantial headlog 14. The development of these addtional rays g to It provides a concave conical surface tangent on its lowermost portion to ray f of the lower development and rising gradually and terminating in the headlog 14 at ray k. This upper section of the bow employs two such concave conical surfaces each having its apex at X and each extending forward of and above the convex conical surfaces of the lower development. I have found that best results are obtained if the two concave conical surfaces are substantially equal. Thus, in effect, two conical surfaces determine the surface of the lower bow and an additional two conical surfaces tangent to the lower cones determine the surface of the upper bow.

The headlog of a heavy duty vessel generally consists of abroad flat'substantial member securely mounted at theforemost upper portion of the bow. Such headlog is provided to enable a vessel to forcibly contact another vessel in providing or receiving movement'and steering control between such vessels. Thus, the headlog is of great importance in the towing and pushing of barges and consequently must be substantial in order to spread the stress when contacting the power vessel as well as for steering control... Theheadlog 14 on my improved bow awareneis clearly illustrated in Figs. 1,, 3' and 4;

In the conventional design of any seaworthy vessel it is necessary to have sheer forward and aft so that in case the bow goes under while moving at any speed, the vessel deck would not act as a diving fin on a submarine. Accordingly, I provide the vessel of 'my invention with such sheer as generally indicated at 16 which is the vertical distance that the headpoint 13 of the bow rises above the, highest portion of the middlebody. My invention may however be applied to vessels with no sheer.

As illustrated in Fig. 2, a barge or vessel is commonly designed with a central load carrying middlebody 7 having similar bows on each end. Ordinarily, loads are not'carried in the bow or stern but are restricted to the middlebody 7 which exists between sections 6.

Fig. 3 is a bottom perspective view illustrating the development of my bow and showing a partialcut-away view of sections to 6. There are many andvaried ways in which the framing supporting the shell of my improved bow may be accomplished. A type commonly employed is the conventional transverse framing in which the supporting frames run across the beamof the bow following the shell of the bow and are joined in intimate supporting contact. withsuch shell. As for example, such transverse framing in Fig. 3 would run on the inside of the shell of the bow at the intersection of such shell'with sections 0 to 6. Such framing may consist of steel angle irons or any other suitable steel supportingmembers.

While conventional supports, and framing may very easily be employed in supporting the surfaces developed.

by my bow, it is equally true that more recently the less expensive method, known asparallelframingmay be employed. To employ parallelframing in my bow would involve the running of frame members along the rays of the cone used in developing the lower surfaces of the bow. Such parallel framing is less expensive and less difficult to install and will work equally well' with the bow of my design.

Fig. 4 shows a perspective view of a completed bow embodying my invention, illustrating the location of. the headlog 14, point X and further showing the inter-relation ship among the head log 14, the concave conical surfaces 17 forming the upper shell portion of the bow, and the convex conical surfaces 18'forming the lower shell portion of the bow. A bow embodying'these developments is extremely effective in granting the hull seaworthy characteristics.

Another important feature of my invention lies in the fact that the shell of this improved bow may be developed from sheets which are not plastically deformed. Ordinarily, in developing a conventional model bow having the desirable characteristics commonly associated with V- shaped bow sections, it has been necessary to plastically deform such plating. This involves considerable effort and expense as it requires that the metal plates in effect be bent in two directions at the same time. Such action imposes great strain on the metal and is extremely difficult to control. By employing the bow of my invention, the problem of plastic deformation is avoided since a flat plate cut into the proper shape such as illustrated in Fig. may be fitted over the frame or stiffening members of the bow with elastic deformation only. By the term elastic deformation, I intend to refer to the bending of bottom and hull plates in one direction only. Thus, a tremendous saving is achieved since the expensive process involved in plastic deformation is avoided. Furthermore, it is now possible to apply a continuous bottom plate or sheet to a hull Without providing special separate plates for the bow since the plates used in the bottom may be elastically deformed into shape and may continue on up to provide the shell necessary in the development of the bow. Illustrated in Fig. 5 is a portion of a flat sheet 19 of metal which after being elastically deformed is suitable for use as one-half of the bottom shell of the hull including the bow'portion thereofi After the elastic deformation of this sheet 19-so thatit will coincide with the conical surfaces above described, edge 20 of this sheet 19 will lie on the centerline of the hull bottom, forward edge 21 will be joined to the lower portion of the headlog 14, and irregular edge 22 will be joined along the chine line to the side plating of the hull; Thus, it is possible for a single sheet ofjmetal to provide an entire one-half of the hull bottom for the barge. The inexpensive method of longitudinal machinewelding along the edges of a number of plates in a flat horizontal position may be used to form in effect one single plate which may be used to provide one-half of the; bow plate.

The chine. line, the abrupt break. between the bottom plates and the side of the vessel is generally developed by a bilge radius such as for example, a six-inch radius. This radius is generally provided in order to achieve a smooth surface at that point which would not result if the bottom andsides of the hull were joined directly in a angle. However, various angular portions known as knucklesrnay also be used at this point andin fact any method of joining the platesat this point is satisfactory for the purposes of my invention.

As pointed out above, the location of point A is critical in the. development of the bow embodying my invention. While the location. of point A has been broadly discussed above, my preferred embodiment as fully illustrated in the appended'drawings involves the location of point A aft of section 6 and aft. of the most forward section of the bow by about 150% of the length of the bow. Thus, I have secured very desirable. results when point A is aft from section 0 by 150% of the longitudinal distance between section 0 and section 6. I have also. found that when point A is located laterally from the centerlineof the hull by about of the beam or width of the. hull. at its widest point, very desirable results are achieved. My preferred embodiment also requires. that point Avmust be located so that one ray of the cone emanating therefrom is tangent to thebottom. plating of thehull. This consideration involves the recognition of the existence of the deadrise since it'is the deadrise that determines the angular degree from the baseline where point A must lie. This last requirement is necessary in order that the surface will have a gradual rise and not an abrupt one as the surface passes from the bottom of the middlebody onto the shell of the bow.

I am well aware that the surfaces of cones have been employed by others in developing hulls and bows for various vessels, however, the critical location of points A and X provides a bow which has hitherto been undeveloped and which provides a seaworthy vessel which may be constructed inexpensively, with little difficulty, and not involving plastic deformation of the plates involved.

Commonly, barges of the bulk goods type have really no bow and stern since it is often desired to push them in either direction. Accordingly, while the above discussion has centered upon the development primarily of a how, it is equally true that my bow development provides a very efiective stern or in effect an improved bow on each end of the barge. This is equally true in the design of towboats and tugs, except for the modifications required to introduce power plants into these vessels.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims or the equivalent of such be employed. t

I therefore particularly point out and distinctly claim as my invention:

1. In a hull construction for water supported vessels, an external bow portion comprising two equal convex conical surfaces joined along a line defining the centerline of the hull bottom, each such conical surface having its apex located laterally from the centerline of said hull by about 125% of the beam of said hull and rearwardly from the most forward point of said bow by about 150% of the length of said bow portion, each such conical surface extending in a gradual upward direction from the baseline of the hull bottom.

2. In a hull construction for water supported vessels, an external bow portion comprising a headlog, an upper shell portion formed by two equal concave conical surfaces joined at a common apex, said apex being located at the intersection of the centerline of the hull with the lowest portion of said headlog, each said concave conical surface extending laterally of and from said centerline and rearwardly of said apex, and a lower shell portion formed by two equal convex conical surfaces joined along a line defining the centerline of the hull bottom, each such convex conical surface having its apex located externally of and spaced laterally of said hull and rearwardly of the bow, each such convex conical surface extending in a gradual upward direction from the baseline of the hull bottom, and each said concave conical surface being adjacent to and joined with one said convex conical surface along a line of common tangency between said surfaces.

3. In a hull construction for water supported vessels, an external bow portion comprising a headlog, an upper shell portion formed by two equal concave conical surfaces joined at a common apex, said apex being located at the intersection of the centerline of the hull with the lowest portion of said headlog, each said concave conical surface extending laterally of and from said centerline and rearwardly of said apex, and a lower shell portion formed by two equal convex conical surfaces joined along a line defining the centerline of the hull bottom,- each such convex conical surface having its apex located laterally from the centerline of said hull by about 125 of the beam of said hull and rearwardly from the most forward point of said hull by about 150% of the length of said bow portiomeach such convex conical surface extending in a gradual upward direction from the baseline of the hull bottom, and each said concave conical surface being adjacent to and joined with one said convex conical surface along a line of common tangency between said surfaces.

4. A hull construction for barges comprising a stern section, a load carrying middlebody and a bow section,

the shell of said bow section comprising a flat vertical headlog 'extendingat the foremost portion of said bow, the lower surface of said headlog being joined to an upper shell portion formed by two equal concave conical surfaces joined at a common apex, said apex being located at the intersection of the centerline of the hull with the lowest portion of said headlog, each said concave conical surface extending laterally of and from said centerline and rearwardly of said apex, and a lower shell portion formed by two equal convex conical surfaces joined along a line defining the centerline of the hull bottom, each such convex conical surface having its apex located externally of and spaced laterally of said hull and rearwardly of vthe bow, each such convex conical surface extending in a gradual upward direction from the baseline of the hull bottom, and each said concave conical surface being adjacent to and joined with one said convex conical surface along a line of common tangency between said surfaces.

5. In a hull construction for water supported vessels, an external end portion comprising two equal convex conical surfaces joined along a line defining the centerline of the hull bottom, each such conical surface having its apex located externally of and spaced laterally of said hull and longitudinally remotely from said external end, each such conical surface extending in a gradual upward direction from the baseline of the hull bottom.

6. In a hull construction for water supported vessels, two separate external end portions, each said external end portion as defined in claim 5, in which said external end portions are joined together by a load carrying middlebody.

References Cited in the file of this patent UNITED STATES PATENTS 1,013,024 Lake Dec. 26, 1911 1,805,669 Liamin May 19, 1931 2,185,430 Burgess Jan. 20, 1940 2,347,077 Burgess Apr. 18, 1944 2,400,771 Moxham, Jr. May 21, 1946 2,665,656 Williamson Jan. 12, 1954 FOREIGN PATENTS 448,076 Great Britain June 2, 1936 653,656 Great Britain May 23, 1951 923,443 France Feb. 17, 1947

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