CA2037833A1 - Vessel for conveying a liquid cargo - Google Patents

Abstract

ABSTRACT
A vessel comprising at least one cargo hold provided with a rigid outer wall, a flexible, liquid-tight container so being present within said outer wall for conveying a liquid cargo therein, whereby the rigid outer wall is at least partially provided at its inner side with a layer which is substantially made of a material having a pressure distri-buting property.

Description

2 1~ 3 1, J ~ ~J

~:SS~L ~ ~2N~X~G A LIQ~D ~;O

The invention r~lat~ to a ve~el c~ pri~in~ a~ le~st one 5 cargo hol~ pr~vlded wi~h a rigi~ outer wall, a ~lexible, licluid-~igh~ c~n~ainer ~o b~lng pr~sent w~thln 6aid outer wall for conveylng a li.quid car~o ~h~rein.

Suah a ve~ nown f~om Du~çh P~'cen~ Sp~ification No.
NL 72.0520~, wherein a b~g whlah, when ~illed with l~quid, 10 Will $ill 'che car~o hold ~orms the flexibl~, liquid-tight con~zliner . ~hl~: known vessel h~s ~een designed ~n ox de~ t4 mimini~e th~ rl~k of leaking o~rgo hs:~ld~3, e.~, qau~ed l:)y coll~ n, whereby the li~uid carg~, ~uch il~ oil, may es~ape. Suoh a ~lexible bag i~ much b~tter a}~le ~o resi~;t 15 deform~tion~ h~ut a~tually t~arlns~, than ~he rigid ~teel con~ructiQn. At the same timo the use o~ ~uch ~ag~
~ender~ the pa~'&ial or compl~3 c.le~ning o~ the in~erior of the cargo holds redund~nt. The ~g~ may be adapted ~or relatively Rasy r~3pla~emen~, and ~h~ ~aam~ ~ag~ may b~ use~
~0 rep~atedly for ~he same typ~ o$ liquid, e.g. oil. In p~r-ticular in car~o hold~ in whi~h ~wc~ or more bags ~re p~o-vided it will be possible tc~ carry ~3everal types o~ oil or other li~uid~;~ wnereby ea~h ~me ~ ame ~ag is u~ed ~o~
~he E3~;me typ~a of liguid, &0 that aleaxling ~ecome~ ~ub~tan-25 ~ially redundan~.

A clrawb~ck o~ ~he know~ ve~:el is ~h~t in the even~ that thet~e~el 1~ ssriously damaged it i~3 not exclud~3d th~ after th~ rigld out~r wall of the ~a~ h~ld h~ ~een bre~ohed, ~ a r~ult oP ~ ~al~mity, al~o th~ bag~ in whi~h the cargo is ~tored will tea~. It ~t~nd~ to r~on th~t ~ f~ee ~ut~low ~f the ~a~go, e~. o~l vr Ghemiç~l~, m~y ~au~ enorm~u~
~ama~e to the environment.

2 ~ ~ ~ $ ~
~he o~i ec:t o~ th~ present inv~nt lon i3 to provldQ ~ Ve$;~
for ~::onv~yin~ a ll~u~d ~rgo, ~hsreby ~he rl~k Of lf~king cargo hold~, e.g. as a con~esluence o~ a coll~s~on, i~
ex~luded or at lea~t min~mized.

5 In order ~o accompli~h that ob~ective a vessel o~ the kind mentioned in the preamble i5 ~haracter~z~d ln that the rlgid outer wall i6 at le~t pa~ lly provid~d at tt~ inner ~ide with a layer which i8 subst~ntially macle o~ a materlal - - -having a pressure di~tributing property. :rhe ~tr~snç~th 10 propertie~ o~ thi~ m~teri~l are ~u¢h thnt in th~ even~e of e . ~ . ~ colli~ion ~he ~o~c:e~ exer~ed on t-h~ rigid outer wall are distributed by E:aid ~ayer, e:o that the oaaurren~e o~ high lo¢al s~re~ses, ~7hich ~ ht ~:on~ti~u~e ~ ri~k for ~he ~lexible, l~uid-tight cc-n~ainer, is prevente~l, Th~
15 ~reng~h propertie~ o~ the material are ~ur~hermor~ ~uch th~'t ln ~he ~v~n~ ~hat ~h~ sheet B~s~e~ bend~ lns,~ard~ 'ch0 layer will remain suf~iciently in~ t, so that sny contac~t b~tween ~harp S~t~el edç~e2 o~ ~he d~maged rigid outer wall ~nd thb f le~ibl~ llquid-~lght ;:ont~iner iB av~ided . Said 2~ ~ontaine~ ~ for ~xample made of a polymer, e.g. polyethy-len~, which i~ suffici~ntly flexi~le and which ~ abla to re~ he corr~ eness o~ e.g. c:r~de o~l ~or ~he li~e span of a ve~sal. It iæ noted tha~ the tsrm rigid outer wall ~ b~ e~ ~he ~hip~ 3kin - i~ al~o hle~nt ~o Gomprise 25 upright ~nner ~ide wall~ the ~r~o h~ld.

one embodiJnent ~f a vessel acGord~ng ~o the inven~ion i~
charac~eriz~d in 'chat ~he ~ter~i~l o~ whi~h t~ lay~r i~
sub~tanti~lly mad~ has a hi~h eners~y di~E~ipating pow~r. When be~i~e~ ~he ~ d c~uter wall and ~h~ xible, liqu~d-ti~ht 30 c:on~ain~r a~ ~o th~ ma~erial o~ th~a layer ha~ ~n ener~y d~lp~t~ng pc)wer, the ri~k ~:~at the c~ nt~ner will t~ar, e.g. in the ~vent o~ a col~ iæion, will practlo~ly 13e ~xc~luded .

~ ,rJ ~ 3 ~
Ano~her emh~dimsnt oP A VB~33~l As::cording to ~he in~ent~on :L8 s:~har~ct~r:lz~d in th~t the l~y~r i~5 ~ub~an'clally mad~
up by ~ ~o~ layer. Said ~oam ~ayer ls prefer~}:)ly ~ ~yn-thetic ~oam layer o~ prefer~bly polyurethan~ r~in or 5 polye~hyl~n~, or a na~ural material wi~h ~he ~a~e pre ~ure distribu~ing property.

Ano~her embodimsn~ of a vessel according to the inv~ntion is charaoterized in that the layer ~s a ~1r~t layer, which- ~ ~
$~ a~t par~ially provid~ at l~s inner ~ide wi~h ~
10 reinforced ~e~ond layer, wh6~reby an sla~tic/plastic third l~yer i~ provi:l~d en ak least par~ o~ the inner ~ide ~f s~id ~e~ond layer. Be~ause c~ thi~: it is pr~vented that, even in ~he sv~n~ oi~ extr~me calamiti~, the ~hip ' 8 cargo ~an leak ou~.

15 Another embodlment of ~ ve~el accordiny to ths invention is c:h~r~aterized in th~t ths~ wall of the ~lexible, liquid-ti~ht container be~rs ~gains~ the layer ~i;u~ ntially made o~ ~ materi~l haYing a pre~sure diçtri~utin~ prDperty or against the ~la~tic/pla~tic layer, a6 th~ ca~e ~ay b~, ~o a6 to ~orm a lining.

T~e ~n~n~ion will be expl~ine~ in ~o~e detail with refe-r2n~e t~ a few figure~ u~tr~ted in a drawin~, wherein:

~gure~ 1 and 2 very d~agra~m~tic~lly ~ trate ~ cargo hold o~ ~ V~Bel ~c~ording ~o ~he inve~ i~n;

figure 3 illustrate~ a de~ail, indi~ak2d by means oX a d~tted ~role, o~ figure 3;

~igure 4 ~hows several step~ in the phenom~non o~ collision with ~ ~yn~h~ti~ double hull;

~'7 ~3~j ~igure 5 lllu~tr~te~ energy ~orpti~n ~or d~er2nt doubl~
hull aonc~ptæ ver~u~ the penetration depth in CAS~ 0~ ~olli-eion, and figur~ 6 ~how~ a compari~on of cri~ri~ or ~he dif~rent double hull conaep~.

In ~lgure 1 a cargo hold 1 of a vessel accor~ing to the invention ~an ~e distingul~hed, ~aid ~go hold 1 bein~
~ubdivid~d into s~v~ral compartment~ 3 by mean~ o~ inner ~ide wall6 ~. ~ai~ aarg~ hold l contain~ ~ ri~id outer wall, a ~hlp'~ ~kin 4 in thi3 case, ~t ~h~ lnn~r ~ide of whia~ a fo~m layer S i~ provifle~, whiah i~ made o~ a ~te-rial having a high tenough~ compre~lve stren~th and a~
high an energy di~sipating pow~r aæ po~ le. ~ ~lexible, li~uid-~ight c~ntainer bea~ ains~ the ~oam l~y~r 5 ~o as to orm an ~lnner) ll~in~ 6.

The ~oam layer 5 and the inn~r lining 6 pr~rably have ~h~
followin~ prop~xtie~

~pec~ia gravity 50 - 1000 500 - 3000 kg/m3 ~0 max. compr. ~e~ 3 MPa tensile ~trength 4~ - 70 MP~
~tr~tah ~50 The thia~ne~K o~ the foam lay~r S and ~h~ inn~r lin~ng v~rie~, depend~ on e.q. the ~ype and th~ ~2 0~ the 2~ ve3~ and rang~ from ~.5 - 3 m ~or th~ ~o~m lay~r and ~rom 1 - 5 cm for th~ i~ner lining.

A c~bin~on o~ ~hi~ ~oam l~y~r 5 and the f~exi~l~ inner lining 5 e~si~y yi~ along with th~ mov~ment~ ~f th~
~hip ~ ln 4 . ~her~ ~re ~ever~ lbilitie~ of prov~ din~

the cor~in~t~on o~ the ~oam lay~r ~ ~nd th~ ~lexib~ nn~r llnlnq 6:
.
1. ~he~ ~oam l~yer 5 and the inner lining 6 are only provi~ed along the ~hip ' s ~kin 4, whereby the att~ch-ment o~ the f lexible inner lining ~ ~o the inn~r ~ide wall~ 2 of the o~r~o hold 1 requlree addition~1 provi~ions ~igure l).

2 . The ~oam lay~r 5 and ~h~ f ~ exible inner linln~ 6 are prov~ ded ~lony the 6hip ~ ~ 3kin and ~he upri~h~ inner side wall~ ~ o~ ~he ~argo hold ~. ~ho g~am layer 5 b~aring against th6~ inner ~lde walle 2 ~nay he much thinn~r 1;han th~ foam laye~ 5 b~ring ~gainst th~
inn~r ~ide of ~he ~hip'~ ~lcln 4 (flg ~h~ Poam layer 5 has a ~our~old ~mGt;lon S

a . ~i~txlbutin~ the forc~ whiah i~ exerted on the Chip ~ B
sk~n in the event o~ a ~alami~y, a~ a r~ul~ c-f which 'che ~ur~en~e o~ loGal high p~ak ten~ion~ on the inner l ining 6 i~ pr~v~n~ed;

b. E~ec~t~ng ~ ~pacin~ l~etw~en ~h~ f3hip'6~ ~Xl~t 4 (b~ea-2~ ch~s~g ~h~?et ~çel! ) and ~he ~lexible inner lining 6;

c. Main~ining ~aid ~pa~ing when, e.g~ in the e~renk of a ~ol~i~lon, the ehip~ ~kin ~o~re13 inward~; and d. Dl~lpating (par~) of the ~nergy which ia trar~ rre~
to ~he ~1ipl5 ~kin, ~,g~ i~ the e~ent o~ o~ lon.

In t~e ~vQnt o~ A ç~ on b~w~n ~r~ o~e~ and a ve~el h~ving il ¢ar~o hold 1 the fo~lowin~ ~tages ~n ~ p~inc:ipl~
be di~inguioh~

.'3 ~J

- Th~ ob~ec:t pen2trate~ the ~ 1 E;hip'e ;kin.

The ob~t pene~r~ke~ ~nto the ~hip'~ hold, whereby the ~oam la~er 5 prot~c~ ~h~ inner linihg ~ eca~se the volume o~ ~ho car~o hold ~ i~ becoming 3maller~ the p~es~ure in ~he oa~go hold ~, will inorea~e ve~y f~e~, whereby air present above the cargo e~ape~ until a maxi~um pr~sure in the ca~go hold 1 i~ ~x~eeded.

- The fstee~ deck or other parti~ions become defsrmed and break if no ~ ure~ have b~en ta~cen ~o prevent ~hi~. The lo foam laysr ~ lg loaded at the maximum pre~ure now and the penetr~ nq ob~ e¢t i~ halted .

- The penetratin~ ob~ect and the v~3~;~1 become d~t~ched from on~ anothe~r. ~h~ Poam layer 5 and the lnrler lin~ng 6 ars~
ten~ioned ~ ront o~ the ~pening caueed by the aolli~ion and pr~vent ~he car~o ~om flowing/leakinq out tsee figure 4~. The e~f~c~t o~ the pres~ure diOEtril~ut~ng layer, in cc~lna~i~n wi~h a ~lexible ~nn~r tank ~po~s~bly prote~ted by a ~ s ~ibr~ l~yer (or otherwi~) at the outside, ~o that in the event c,~ ~ ccalli~lon or of th~ vessel xunning a~round ~he inn~r tank remains intact) i~ to a ~on~ide-~a~l~ d~gre~ ~au~d by the ~anergy a~or~in~ c~apa~ity which is cr~3at~d ~ a re~ul~ of a pre~ur~ bui ld-up ira the aollided ~an~, and of the r~sul~ing deforrnation of the inne~ wall6 0~ ~aid tank. Thi6 pheno~nenon does not occur with a single or doubl~ st~ kin, sin~ the tank will ~ax~ ~o l~a~, ~o ~h~t no pr~sure i~ }:uil~ up and no en~rgy s:an di0~ipat~ ~ a re~;ul~ o~ the ~ormation o~ the 'cank wa~ 1~. This ~3nergy ~b~or~ng e~ec:~ wa~
ca~cul~ ed, and i~ illustra~ed ~n `1~ur~ 5 ~ ~omp~red tv ~teel ~kin~. Figur~ ~ ~how~ the ~ult~ o~ ~h2 ~a~i-bilit~r ~tu~y ~çhat ha~ been carried out, i.~. th~ o~fe::~

7 . ~ 3 of ~he decre~se o~ the arS~o volur~ per dw~ ~hip c~p~city, the ao~ n~ ~he critioal energy ~upply.

Sinc~e the foa~ lay~r S iB les~ ~la0tic than t~ inner lining 6, ~aid ~c~a~ l~ye.r 5 ~ight be~ome breached ~n caE:e of Yery 5 ~x~rem~ c:alamit1~s, as a result Of WhiC;h the ~lexible inner lining 6 mls~ht run the ri6k o~ tearing as yet, resulting in the cargo le~k1ng ollt. A~ ~ ~afegu~rd ag~in~t ~ch extreme calam~ ti~ a ~pea~ ~l fe~ture o~ a ve~el ~ordln~ to th~
invention i~ ~h~t at it~ inner ~ide the foam layer 5 is 10 provided with a rein~orced layer 7 oî synthE~ lbre~ ~or any oth~r material re6i tant to ~hoa~c), on the inner ~ide o Whic:n ~n el~'çic/pla~t:5 & l~yer 8 t ~ ~ro~lded . In that ca~e 'ch~ ~lexible innsr lining 6 b~ars ag~inet ~aid ela~-ti~:/pla~t~P layer 8 ~ f i~ur~ 3 ) . S~ d layer~ y al~o be com~ined ~c~ for~ s;~ne compo~ yçr, o~ Go~e~ Al~
another ~qusnce of l~y~r~ ~all withirl ~he ~cop~ o~ ~he inv~n'cion, ~EDX ~x~mple ~ G~enae ~orr~pon~ng ~o the above describ~d ~equence on the understand~ng that th~
po~it:ons 0~ th~ fo~m l~er ~ ~nd ~ne el~lc/pla~ yer ~o 8 are mutu~lly exchang~ad. ~he ue:e o~ several lay~srs o~
~nthet~c: ibxe~ ;tead of the u~e ~ one ~yn~het~ o layer i8 0:~ couree al80 possible, ~he advantage of ves~el acoordln~ to ~ha invention in compa-ri~on with the ve~el desari~ed in Dutch Pat~nt 8peoi~i-aation No. Nh 72.0520~ i~ not only that the ~1~3k o~ l~ak~ng c~rgo hold~ xcluded/minimized, ~ut al~o tha~ th~ ~argo i~ in~ula~ed ~y th~ f oam layer 5, ~o that ~n energy 6aving 1~ re~llz~d. Th~ u~e of polyurRthAne r~sln ts~ ~orm t;he f~m lay~r ~oxeov~r haY ~ha ~dvantA~ ~ha~ ~herE3 i~ less intern~l a~r~ n ln the car~ hol~ d ~hat - ~eoa~se o~ it6 low ~p{~ci~ic w~ight - ~h~r~ i~ h~rdly an increa~e in the w~ght o~ the ve~sel. A ~inal advanta~e o~ ~h~ ve sel ~ccc~rdi~g to t~e inventiorl ~ that ~he~6! 1OE ~ubst~ntially no 105B 0~ g~ o~p~ ity, wh~oh i~ t~ a sub~tant~l degree ~he c:~se w~th E!l ve~ aor~lng to ~he e~bove-ment~oneà
tch P~en~ Spscification. Indeed, w~Gh $hi~ knowr~ ve~zel a r~31a~vely large ~paclng betw2erl the ~hip ' ~ skin and ~he inner tank i~ required, due to the naces~ity of 0~6ett~ng S the pow~r tran~mittlng e~fe~t~ o the c:~nnection~ between the ~hip'~ ~kin and the ~nner tank occurr~ng in ~he event of a col~ie~on . The ~pac~e between the ~;hip ' 6~ ~kin ~nd 'che inner tarlk with this known ve~el may furthermorla ~orm an explo~ion spaae, ln aa~e explosive ~ase~ are rele~6ed into 10 thi~ ~p~C~ a~ a re~ul~ of e.g. a glrz which ha~ broken out on ~aid ve~el.

It i~!3 no~ed thAt in ~he ~vent t~ the VRB 6!!l acc~rding to 'ç~e inverltion runs aground, a~ a re~:ult of ~ ion ~rith e . g . A roc~k pro~ecting ~rom th~ bottom o~ ~he ~e~ id roc:k 15 will c~use le~6 damage to the ~ree;~el, becau6e on the ono h~nd the r~ tive moYement oi~ the roclc will be }:rake~d very ~xor~yly ~y the ~m layer 5, and on the o~her hand ~here Are no ~ix~d, ri~id cvnnectic~n~ betw~en the ~hip'~ in 4 and ~he ~l~xib~ e inne~ lining ~ . ~hl~ in c::ontras~ to that 20 whiob i~ de~cr~b~d in Dutch P~tent ~pecific~tion ~o. ~1, 72~0~0g, wherein ~ixed connectionæ ax~ pr~n~ b~w~n the ~hip ~ c 6}cin and the inner tank .

Claims (5)

1. A vessel comprising at least one cargo hold provided with a rigid outer wall, a flexible, liquid-tight container so being present within said outer wall for conveying a liquid cargo therein, characterized in that the rigid outer wall is at least partially provided at its inner side with a layer which is substantially made of a material having a pressure distributing property.

2. A vessel according to claim 1, characterized in that the material of which the layer is substantially made has a high energy dissipating power.

3. A vessel according to claim 1 or 2, characterized in that the layer is substantially made up by a foam layer.

4. A vessel according to claim 1, 2, or 3, characterized in that the layer is a first layer, which is at least partially provided at its inner side with a reinfor-ced second layer, whereby an elastic/plastic third layer is provided on at least part of the inner side of said second layer. Because of this it is prevented that, even in the event of extreme cala-mities, the ship's cargo can leak out.

5. A vessel according to any one of the preceding claims, characterized in that the wall of the fle-xible, liquid-tight container bears against the layer substantially made of a material having a pressure distributing property or against the elastic/plastic layer, as the case may be, so as to form a lining.