US2162822A - Ship hull and method of constructing it - Google Patents

Description

June 20, 1939. G. 1 -PARSONS v2,162,822

SHIP HULL AND METHOD OF CONSTRUCTING IT s@ y lNvENToR A ATTORNEY 3 Sheets-Sheet 2 G. C. PARSONS SHIP HULLVAND METHOD F'CONSTRUCTING IT Jane 2o, 1939.

I `Filed June 23, 1958 June 20, 1939.

G.- c, PARsQNs SHIP HULL AND METHon'oF'coNsTRUc'T'ING 1T Filed June 23,"1958 s sheds-sheet s INVENTOR a.' qnaul l BY @ ..ef E? .,g,

ATTORNEY t messa June 2o, 1939 :UNITED STATES PATENT y ori-ica snnrnunr. AND tgig or cons'rnuc'iii George Chauncey Parsons, New York N. Y. Application June 23, 193s, serial Np. 215,325

9 cnims. icl.' 114-19) This invention relates to hulls for ships, ilying boats. etc., and methods oI- constructing the same.

The principal object of the invention is to provide a simple, cheap, metal hull construction, suitable for small ships, say 25 to 60 feet in length. Metal hulled ships have numerous advantages over wooden. They may be weldedso that there f is no possibility of water seeplng in through the seams. They are immune to the action of marine borers, like the teredo. A strength, and,.if kept properly painted, almost indefinite life. The chief obstacle to the'productionl of small metal hulled boats has been their cost. 1

For ships under 60 feet, the cost of rolling or otherwise deforming initially dat plates to give them the desired curvature, both transversely and longitudinally of the ship, is prohibitively ex pensive.

According to the present invention, therefore, the hull is made angular in section. The simplest angular hull cross-section which is'practicable is one having a V-bottom with .a pair of straight -transverse sections from each side of the keel to each chine `and a second pair of straight transextending from each chine to the corresponding gunwale. The four sections of sheathing can each be formed of a long single curved plate.

It will be understood, however, .that where reference ismade to a single sheathing plateor section the'term is meant to include any iiat sheet composed of a plurality of sections welded or riveted together so that, geometrically speaking, f

. being parallel to every other section. -If, then,

it assumes when iiexed to hull form the curved vforms.characteristic of a unitary sheet of metal. In practice it is rarely possible to secure sheets of metal of suclent length to form one entire sheathing section so that usually itis necessary to splice two or more plates together.

40 Theabove hull form requires five longitudinal frames; viz.: vtwo gunwales, a keel and two frames at the chines. The four sheathing sections are secured at their marginsl to these ve frames,

4 usually, but not necessarily, byl welding. Ex-

sheathing is exceptionally strong and heavy it -is usually necessary, or at least highly desirable. to have a number. of intermediate. longitudinal 'frames to support each sheathing section between its welded margins. Similarliziit is usually necessary to use ribs', especiall here such intermediate frames 'are used; as-inthat-case such frames' have to be supported.by. ri l 55 The inventionis alsa-app Y They have great' verse sections at an angle to the rst sections and Y lcept in the case of small boats or where the in lwhich there are seven or morelongitudinal frames, but the form having only ilve is preferred as it meets all ordinary requirements for hull .design and is simplerand cheaper to construct.

, merely flexing th m to hull form. m

There are two cases to consider: flrst,'that in 'which the transverse sections taken at intervals from stem to stern through any one sheathing plate are all at the same Aangleto the vertical; second, thatv in which the angles of such sec- 15 tions change. The rstcase 'is ordinarily used only for certain parts of the hull, such as the deck or certain parts oi the hull proper. Its constructional principle will not give a satisfactory hull form if used throughout. It is almost universal practice to form the hull so that in the topsides such sections are more nearly vertical amidships than they are near the bow and stern. Foi-the bottom sections those nearest the bow are nearer the vertical than those further aft, the sections the parts of the ribs opposite each sheathing ,35

plate or such part thereof are straight, the plate can be made to contact with the corresponding parts of each -rib throughoutv its length, without curving the outer edges of the rib sections. This is due to the .fact that the sheathing can be bent 40,

to form without bending the plates in any other plane, i. e., without twisting the endsrelatively to the middle: and so forth.

In the second case, the fact that the transverse sections through each sheathing plate, either throughout the length of the ship or for a considerable part thereof', make different angles to the vertical means that the sheathing plates are not'j only bent longitudinally, but also have 'their 50 'ends'tjwisted relatively to their middle section.

The;` or such twisting is that the sheathing plates are bowed outwardly transversely so thatthey cannot contact with a straightrib section except at its 'ends and edges. This transverse 55 bowing or curving of the sheathing greatly increases its strength and stiiness so that in some cases it is possible to dispense with the ribs and/or intermediate longitudinal frames. 'I'he transverse bowing of the plates also greatly improves the looks of the boat as it avoids any dead-at appearance on the hull sides and/or bottom.

Heretofore in making small boat hulls of angularl form it has been customary .to use ribs and to force the sheathing plates inwardly to make them conform to the straight edges of the rib sections.l The result on thehull appearance was disastrous. According to the present invention, instead of bringing the sheathing in to t the framing, the latter-is either'actuallyor in effect moved outwardly to t the natural vtransverse curves of the sheathing. Usually it is only the intermediate longitudinal frames which are moved outwardly so that the sheathing contacts with the ribs only along-the gunwale, chine and keel. It is not necessary" that thevribs contact at those points, even. Whether the' sheathing plates contact with the ribs throughout or are wholly or in part spaced away therefrom, so that the plates contact only with the main and intermediate longitudinal vframes, the sheathing plates haver the same transverse curvature.

It is desirable to space the sheathing away from the rib's, as otherwise, if the sheathing is thin and the ship scrapes along the side of a dockor the like, the sheathing is dented inwardsv up to each rib so that the positionof each rib becomes very apparent.

It is not possible, geometrically speaking, to make the deck of a single flatsheet and give it both sheer and camber. 4Using two plates abutting each other along the c'enter line of the boat at an angle of 170 to 175, both sheer and camber can be given. With such a construction the transverse sections of each half of the stern allhave the same angledeck from stem to to the horizontal.

Two suitable forms l vtrated, by way of example, in the accompanying in accordance with drawings, wherein:-

Fig. 1 is a side elevation of a hull constructed the present invention, the cabin trunk, keel and rudder being shown in g dotted linS;

Fig. 2 is-a bottom pian view of the same'before the n,keel and rudder have been yatline 4 4 of Fig. 1;

Fig. 3'vshows the p`ort side of the hull infront elevation and the starboard side in midship sec- 55V tion;

Fig. 4 is a section on van enlarged scale of the Fig.. 5 is a detailvlewshowing the relationship between the ribs and the intermediate 1ongitudinal frames:

Fig. 6 is a detail view showing the manner in which the keel is connected to the stem;

' Fig. 7 is a midship section through an'alter- .native form of construction; and

Fig. 8 shows a section of the same alternative construction taken near the bow.

As shown in Figs. 1 to'6 inclusive, .the hull comprises four metal sheathing plates III, II

supported by metal framing including ribs I2,v

I3, intermediate longitudinal tubular frames frames i4, gunwales I5, keel I6, stem II and transom i8. Below the metal hull is a built-up wooden keel I9, containing the usual cast iron or lead ballast, all secured to the keel I6 by vertical bolts, not shown. i

lscribed in connection with Figs. 7 and -ing an alternative form of hull construction.

greater in the of construction are illusy up the wooden keel I9, with its tubes. After the keel `I'Ghas Psired curvature before it is placed in position.

'I'he stem is a flat strip of steel curved to shape. The forward end of the channel keel has a. V-

` shaped 'slot cut therein, into which the lower end of the stem is inserted. 'Ihen the two halves of the end of the keel are forced inwardly against the sides of the stem and solidly welded thereto.

The ribs may be formed, as shown, of straight flat strips butt-welded together at the chine line 20 and also to the gunwales and keel. 'Ihe upper ends of the ribs are connected together or to the walls ofthe cabin trunk by deck beams 25. On these beams is laid the deck, which may be of wood or more conveniently of metal plates 26 supported by the beams, either directly or indirectly by means of carlines 2l. Where metal plates are used, as shown, the deck beams are made in two parts welded together along the center line of the boat at an angle of to to give the desired camber as above explained. If desired. the carlines may be forced l upwards against the deck plates by wedges, in the same manner as the intermediate longitudinal hull frames I4.

'Ihe -cabin-trunk 2| may -be constructed in a variety of ways. One method is shown and de- 8 Vshow- In the hull construction illustrated, there are ten ribs and the angles which the various rib sections make with respect to the verticall change from stem to stern, .as shown more particularly inrFig. 3. Thev result is that the sheathing plates are bowed outwardly, especially near the bow, as indicatedy in Fig. 4. Also, the bowing is bottom plates than in the top side plates, as there is more change in angle in the bottom sheathing plates than in the top side sheathing plates.

While the ribs could be cut to i'lt the bowed form of the sheathing plates, it is easier to mount the intermediate longitudinal frames on the ribs so that in constructing the hull such frames can be pushed outwards to meet the sheathing. This system of construction has the further advantage that, by forcing out the intermediate frames after the sheathing has been welded to the main longitudinal frames, the sheathing can be stretched tight under tension. For these reasons the intermediate longitudinal frames areA initially slidably mounted in slots in the ribs, so that by driving wedges 29 into the slots behind the frames they may be forced outwardly against the sheathing plates. When that has been done, the longitudinal frames I4 may be welded in fixed position in the slots in' the ribs. y

In'bullding the boat the first step is to build attaching bolts extending from its upper edge. The next step is to weld together thekeel and stem, as previously explained, drill or cut holes in the keel for the attaching bolts, propeller shaft and rudder head wooden keel I9, the ribs are attached. Each pair of rib sections is butt-welded together and then their lower ends are welded to the keel- I6 in proper spaced relation and with their upper ends in position for subsequent attachment of the gunwales. 'I'he gunwales both horizontally to lit the curvature of the ships side andl vertically in accordancewith the sheer of the deck. 'I'he gunwales areA then welded to the stem and tops of the ribs. .The transom is been attached to they are then bent to form sol . then` welded to the gunwales and keel. Neat, f

'the tubular longitudinal vframes I3 arebent to shape and welded to the stem. transom and tops of the ribs. The deck beams are then welded to 4 the under side of 'the' gunwales and the cabin.

trunk framing is welded to the deck This completes the framing except for the intermediate longitudinal hull frames Il and the deck carlines" 21. p'I'he frames 'i4 are placed in position in the slots in the' forward ribs and then welded to the stern.Y 'I'hey are next sprung into hull form, bringing thenifJnto engagement first with the slotsin the ribsjin the.mi dship section, then with those aft and nlly with'the in the transom. They are then l,held inthatijpcsition in such a way that they`are'free'- longitudinally in vthe slots as well as vlaterally outwards when the time cornestofforce'them outwardly against the sheathing;` i

The next step' ,is vto ,apply fthe hull sheathing. The forward endsof thesheathing plates il are welded tothe and thenexed into contact along their -margins with-the'tubularV frames I3 and lgunwales, i 5.?,3Theyfa'rethen welded along such ec margins-.to theframes alena gunwales is and nally to the transom` -.f The sheathing plates il arezinfsimilargway welded-to the stem i1, tubular frames I j3 ,.keell`fl ,6 'and A transom i8. vAs the sheathingI plates` ,arelap'-,g or butt-welded to the -have the same contour, the plate 36 forming the roof of the cabin trunk can be bent around and welded to all of the frames.4 The bottoms of the frames maybe connected to the inner ends of the deck beams by angle bar cai-lines 3l welded to both the frames and deck beams.

What is claimed is:

' 1. A metallic hull for a ship comprising a frame .having a keel,fa stem, a transom and a plurality of ribs disposed at ldifferent angles to a vertical plane passing through said keel, a plurality of` hull-length metallic sheets fixed at their ends to the stem and transom and fixed at their edges to the frame, said sheets being ilexed and twisted over the ribs into longitudinal and transversecurvatures conforming substantially to the angular inclination of said ribs,

whereby said sheets are tensioned and maintained in said transverse and longitudinal curvatures without buckling.

2. A metallic hull for Aa ship v comprising a frame having a keel, a stem, a stern element and a plurality of spaced ribs disposed -at diierent angles to a vertical plane-passing through saidv keel, a plurality of hull-length metallic sheets fixed at their ends to said stem and to said stern element and connected at their adjacent edges in watertight. relationship. said sheets being ilexed and twisted oversaid ribs into longitudifdriven in kvbehind the iframes il` until the latter not nal and transverse curvatures conforming substantially to' the angular inclination of said ribs, whereby said sheets are tensioned' and ymaintained transversely and .longitudinally curved. 3. A method of constructing 'metallic hulls for ships of angularcross-section comprising welding longitudinal frames tothe angles of theribs," vplacing'intermediate longitudinal frames -in slots along the outer margins of the ribs, welding the longitudinal edgesoi.' the metal sheathing plates` to theiirst mentioned -i'raxnes and then bowing vsaid plates outwardly under tension by forcing e@ gunwales, it 'may be'fdesirable to coverthe joint 3i) by a woodens`trip128;l :"Ne'xt, the wedges 29 are -`only contactwit'h the :sheathing plates but also nforce them outwards under tension to give them aga smoothpevenlycurved-orm fromstem to stern.l What that' isaccomplished 'the 'wedgesare welded to the 4ribs. 'and to'-thelongitudinal frames i4. The frames 'M m'ay then' be welded to the transomf. The endsofthe sheathing .plates iii, ii, oframes i3, it andkeel I6, which project beyond 1 the transom, are cut oif and ground iius'h with the latter.

In the construction shown in Figs. '7 and 8, the'ribs 30 are" bent to forminstead of lcielng formedof straight sections butt-welded together. The'greater number of the ribs are made of a singie piece of metal from gunwale to 'gunwale However, thoseribs in the bow which contact with the stem are, to advantagamade'in two pieces,

so that their lower ends'can be welded to the sides of the stem, instead of its top only. Gusset plates 3l may also be used, as shown, to secure greater,

rigidity adjacent the stem as-iloor timbers.

In this `case the ribs .are of angle form with one web projecting outwardlytoward the sheathing plates,'while the other web extends substantially parallel to such plates. This rib section is much stronger per pound than vthetilat section of Figs.

and keel and to serve 30 1 to 6, and hence' the ribs may be made lighter without sacriilcing strength.

'Another feature of this alternativeform :of construction is the use of semi-cylindrical longitudinal frames 82 at the chines, which also re- -'duces the hull weight somewhat.

The deck beams 33 are also of angle form, but yin this case the laterally extending Awebs `the outside and the deck plates 1I are lwelded directly thereto. This is possible because the 7v0 deck platesv are not curved transversely.

v'Ihe cabin trunk framing comprisesa plurality Aoi.' angle b'ars bent into shallowinyerted U-shaped.

frames I5. each havinguthe' `saine contour al.- thoughthe height of their sides varies somewhat duetothesheerofithe deck. all.

the intermediate longitudinal frames outwardly,

iongitudinaledges of the metal sheathing plates to the first mentioned frames and then bowing said plates outwardly under tension by driving wedges between the bottom of the slots in the ribs and the intermediate longitudinal frames.

5. A method of-constructing metallic hulls as in claim 4, in which the intermediate longitu-l dinal frames are rst welded tothe stem', thenl sprung into the curved form of huil -to bring them' into engagement with the slots in the ribs. -next forced out against the sheathing platesby wedges and ilnally welded to both ribs and wedges. l I 6. A method of constructing metallic hulls for.l boats comprising assembling' a frame for said,

hull, ilexing elongated metallic sheets longitu .dinally and-twisting said -sheets over said frame to stress and curve them longitudinally and transversely into hull form. and. adjusting said ki'iame to conform to `the transverse and longitudinal curvatures of the sheets.

, 7.. A method of constructing metallichulls for ships comprising fixing ribs to a` keel, mounting movable reinforcing members in sa'idribs, flexinjelongated sheathing plates over said vribs and connecting -them at. their adjacent .ledges land lmoving said reinforcing'members outwardly into lform a sheathing having portions stressed and curved longitudinally and transversely, connecting said sheets in Water-'tight relationship and adjusting said reinforcing members to engage the inner surfaces of said sheets.

9. A metal hull ship of the type having an angular cross-section, comprising metal framing including metal ribs, stem and transom, longitudinal frames welded to the stem and-transom and also to the ribs Aat the corners and ends thereof, and intermediate longitudinal frames,

also Welded to the ribs,l stem and transom, said ribs having `slots alongY their outer margin to receive said intermediate longitudinal frames, and metal sheathing plates the length of the ship welded at. their ends to the stem and transom 4and alsowelded along their longitudinal edges to lthe first mentioned longitudinal frames, the intermediateframes projecting somewhat beyond.

the line of contact of the plates with the corner frames to give the framing a transverse curvature corresponding to the natural transverse curvature of the sheathing sections when bent to hull form.A

G. CHAUNCEY. PARSONS.

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