US1778993A - Ship's structure - Google Patents

Description

Oct. 21, 1930 N; AKM FF 1,778,993

SHIP S STRUCTURE Filed Dec. 14, 8' '3 Sheets-Sheet 1 0d. 21, 1930. i 0F 1,778,993

SHIPS STRUCTURE Filed Dec. 14, 1928 3 Sheets-Sheet 2 Wa /Moi pwe T 8 v Oct. 21, 1930.. N. AKIMOFF- 1,778,993

SHIPS STRUGTIJRE Filed Dec. 14 1928 3 Sheets-Sheet 3 INYeu OR Patented Oct. 21, 1930 f g a ,778,9 3

These, pr ements rel te QpanfiQ larly to the rear-endoithe vessel, called generally the aiiterbodyulthe run). "It-is usual ingthe art of 1183 311tGQI lSiil'HCblGH' llQ makethis t; as fine as possible, always, but 'especial-lyso for :the high speed-vessels,- while ,for the slow speed ships, such as cargo boats or. oil .ta-nskers etc.-,- theqrequirements o-f ggrea't {displacements necessitatethisbeing made {much full I it er, butstill-withttheviewioiluia ing itz s'fine as theeonditionsperniit. While thereismo rigid ade katio ine',- veryone 1 i f Tentiate a fine lined vessel from a full lined ne It isin tu t ifi e isbettenfidapfifida r 75 also/Fa gthjeoretiual 1 reas n .s y Wl Gh generally -j usti-fied as {follows z-ezif we snake-la void; or: empty spaeeij ust belowythe water surviace; by; rapidly movingjthroughth Wateran object (of any kind), the water wilhhwve a tendency-tor closeiin atawelocity of approxi- -mately Z m ilghm metr. per sec. v or=46,4 feet per sec. or=27 knots (-in reality this will be less owing to severalcorrection factors etc.). In connection with the foregoing formula it should be noted that the constant 10,33 is in meters and represents the height of a column of water balancing or equivalent to the atmospheric pressure. In other words if the lines of the vessels afterbody were full, or if the stern were cut oil sharply, the water near the surface could not close in (even theoretically), and there always would be acavity, aft of the vessels stern. But at the depth of 10 m. the velocity with which the water would tend to close in would be or about 39 knots. So that even taking into consideration various correction'factors, the void or vacuum could not form even at very high speeds aft of the deeply submerged part of the vessel. Of course the mechanism of the closing in is much more complex and can be more fully explained only by the formation of vortices aft of the hull, as set forth in the Karmans theory of'resistance according fi elin c pusse accompanying drawingsyin cwhich 1-7 the, present' invention, I e

to whichi(Fig; of'the accompanying drawings) h bed'y ie- .ai es; hed r u enifi thea ew lAglo'se's a-certain" amount of v'or 1 flees, which also-moye in the same direction,

li 8131a smaller velocity and thus break fl l yi f h dy 5 Th l nuwali i t nw "between these zvortic'es and the rate at which they ,forn'i and break-away .from the hull "en ab 7 the r s ce O t .1111 'j'(' .n rd il. i

ti n w which. we-ta n eonie rni i "in this is u' q i-i ;T- e1.mes imp tta fa is ih fi i s h b plie a erita ifi n f ma i enr g es t wake'gt i hi *fii e Q lshipsfth iikelefieet i ns gi l ashe altoget ew, Whi hi s the hullf'loca tednear may b altogethe wa'firl inea i imm d telybl t'a e o th fine W1 an ewI e, 1 1 than?- mi'tsthe present usual prajc"ticey-zus the depth increases. Everyone who hash'ad exper ence Wi shipmode nows. thabat 0W Weeds the finer lined model requires-relatively and allhull which-above the surface 111Ly lOOk r I so. f

as fine' as thatv of anyhigll speed vessel of reason *be much more economical- 'fo1' both the lower the higher speeds.

today, may have inyreaility a niilch fuller submerged part of the afteibody, and for-this The-inventionis' clearly illustrated inttli'e ring 41 showsthefiormation ithezwake aift ofithe shiip constructed 'in' accordance with lines of the pipe, V p 7 Fig. 4 is a cross section of the.sh1psafter-- 7 body, and

Fig. '5 shows' a constructioniknown .ias

buttock lines of the pipe, Fig. 3 is a similar View, showing blisters'appearingto be similar to but having nothing to do with the presentimproyement.

In the accompanying.- ;drawing ;I have in thin) lines, and have modified its form as shown by heavy full" lines --M- aaerboay L therefore comprises a combination of: fine lined one at the water surface ands little 7 below it, and of a fuller lined one, belo-w a cer tain depth (say or of the total depth of immersionjdrait). If the economical speed oi the original vessel, from which this sketch;

was made w'as say 12 knots. the speed of the modified vessel'will probably be l lfknots or so. course,theibelt,'connectingjthe two rad cally diii'erent surfaces, the line lined o e-and the full lined one, must be worked out; a, very careful "and gradual manner,

'butfto those versedjin the art this will iibt present any special fdiificulties. For very high speed vessels, transatlantic liners or cruisers, the actualcurves niay. look different,

but: exactly the same idea: will be niaintamed: perhaps in, some cases the lmes of the upper sections, u'st below the water line,

7 will be made still finer than now, which would be benefic iahfrom the-standpoint of wake formatio'nfbut the more submerged portions would be made inuch fuller than they would be at present, this materially re-j ducing the resistance. The appended 3 views illustrate the exact manner in which the lines are made fuller in thelower section, and finer in theupper ones. 7

It is evident that the propellers forthe 'afterbody will have to be designed difierently from the manner in which they would them exactly in the same manner asit does 7 many othertype of vessels. e 'Having now particularly described and as and inwhat waythe'same'hasto be performed, I declare that what I claim isii;

;;1.".'1'A "ships form comprising an yaiterbody composednf"twotypes of curved' surfaices' a finer body being the upper, and thejfuller ,v ,iineabp yb i ga lower, s y" taken an afterbody of a full lined vessel, whose original lines are shown in dotted.v (OT-1.

whichthe' transverse sections of the afterbody have a p'oint 'of inflexion'below the load waterline. v v 452 AK ships form' 'accord-in'g to claim: 1 whose buttock lines hf'av'e' a point i or region of inflexion below the-load waterline." 5: A ships =for1n"according to claim- 1 ,wherein'the' afte'rbody is c onstruoted in; a manner to cause'greaterwake at 'regions of greatersubmerg'en'cethan nearerthe. sur 7 face."

' 6. A ships'i'orm according to claims].

inwhich the transverse:section and the buttock lines of the afterb'o'dy' are interrupted in their 'naturalflcurvature ata; certain depth below the load waterline, and! become after that point, fuller than they would be if the natural curvaturewas continuedin the usual manne qq In testimony my hand. i p 7 I zNICHOLASiXKIMOFF.

be fort-he same vessel with the'aft'erbody of i the usual type, but thisis a matter that does 1 a not concern us in the discussionof the lines of the ship, itself. 7

1 The drawing showstheapplicationof this I V principle to single screw vessels, but it is clear that the same principle without any modification whatever,-is applicable also to V ,inultiple screw' ships withthe added ad- 55 vantage that the appendages (bossing) owing to the fuller formwould be shorter i .and thereby would offer less resistance. 7

There are special forms of vessels, as illustrated in Fig. v5'seldom used, but although enlarged at the midship. section, they have the afterbody of the usual type, that is as fine as the'conditions permit; for this rea' son these vessels have nothing in common with the present invention, which applies to l l H whereof I have hereunto set

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