3 Important Calculations Every Marine Engineer Must Know on Ships

3 Important Calculations Every Marine Engineer Must Know On Ships Facebook  8!" #witter $oogle% &inke'In (interest

APRIL 21, 2014 BY ANANTH T

I ns hi p’ sengi ner oom,anumberofgaugi ngi ns t r ument sdi s pl a yv ar i ousi mpor t ant par amet er ss uc hasl ev el ,pr es s ur e,t emper at ur eet c .Butt her ear es omees s ent i al pa r ame t er swhi c hc an no tber eaddi r ec t l yt hr o ughan yi ns t r umenta st he yd epe ndon anumb erofdy n ami cf ac t or s . Th i sd ema nd st h ema r i n ee ng i n ee rwo r k i n go nb oa r ds hi p st odos omef o r mu l aba s ed c al c ul at i onsbycons i der i ngal l t hos ef ac t or sandwi t hpos s i bl eav ai l abl ei nput s .Ofal l t hei mpor t antc al c ul at i onst hatar et obedoneonboar ds hi ps ,t her eaf ewoneswhi c h mar i neengi neer smu mus tk nowwi t houtf ai l . Fol l owi ngar e3i mpor t antpar amet er swhi c har emos tof t enr equi r edt obec al c ul at ed b ymar i neengi neer sf orr ec or dk eepi ng: 1 .Bunk erCa l c ul a t i on:

Bunk ert er mst of uel oi l i nmar i t i me i ndus t r y .Bunk erquant i t ycal c ul at i oni st hemos ti mpor t antc al c ul at i onwhi c hev er y mar i neengi neers houl dbef ami l i arwi t ht hr oughouthi sc ar eer .Bunk erf uel ,bei nga hi ghv al uedpr oduc t ,hast obev er ycar ef ul l yandac cur at el ycal c ul at ed f or det er mi ni ngt hequant i t y . Thev ol umeofdefi ni t equant i t yofbunk eri nc r eas eswi t hi nc r eas ei nt emper at ur e wher easi t swei ghtr emai nst hes ame.Fort hi sr eas on,bunk eri sal wa y sor der edand me as u r e di nwe i g hta ndn otb yvo l u me . Al s oal l t heener gyandeffic i enc yc al c ul at i onsoff uel onboar ds hi psar ec al c ul at edi n t er msofmas soft hef uel r at hert hani t sv ol ume.( Cal c ul at i onofbunk erf uel quant i t y i nwei ghti nv o l v esman yf ac t or st obec ons i der edmak i ngi tmor ec ompl e x. ) Mos t l y ,t hef our t hengi neerwi l l bet hedeput yoft heChi efengi neerf or   r ec ei v i ng b un k er&me as u r i n gt hebunk erquant i t yf ormai nt ai ni ngr ec or ds . Ment i onedbel o wi st hepr oc edur ef ormeas ur i ngandc al c ul at i ngt hebunk erquant i t y : >  Onc et het ot al quant i t y( t onnes )ofbunk erf uel t ober ec ei v edi sc onfi r med,t ak e s oundi ngofs hi p’ sbunk ert ank s&c al c ul at et heav ai l abl equant i t yoff uel oi l onboar d t of or mul at eab unk e r i n gpl and eno t i ngh owmuc ht o nne soff ue lt ob eb un k er edo n e ac ht a nk&t h et a nks e qu en c eo fb un k er i n g. >  Be f or ec omme nc i ngo fbun k erope r at i ons ,c o nfi r mt het emp er a t ur eatwh i c ht he bunk eri st ober ec ei v edandnot edownt hes t andar ddens i t yoft hef uel oi l .Wi t ht hi s par amet er sc al c ul at et hev ol umeofbunk ert ober ec ei v edi neac ht ankasper

bunk er i ngpl anandno t edo wnt hefi nal s oundi ngl e v el ofeac ht ankaf t erbunk e r i ng us i ngc apac i t yt abl ef ort heeas eofs t oppi ng&c hangeo v ert one xtt ank . Thebas i cf or mul aus edf orc al c ul at i ngt hebunk erquant i t yi nwei ghti s : Mass=Vol umexDensi t y >  I ti st obenot edt hati nt heabov ef or mul a,t hedens i t yandv ol umeofbunk erf uel s h ou l dbek n ownats a met e mp er a t u r e . >  Af t err ec ei v i ngt hebunk er ,t ak es oundi ng/ ul l ageofal l t hebunk ert ank sus i ng s oun di n gt ap ea ndn ot edo wnt het a nkt empe r a t ur e .Us es ou ndi n gp as t ei nt het a pe whi l emeas ur i ngdi s t i l l at ef uel s uc hasMDO f oreas yr eadi ng. >  Shi pal way sdoesnotfl oatwi t hev enk eel s ot hefl oat i ngc ondi t i onsoft hes hi p s uc hast r i m andl i s ts houl dbewel l not edwhi l et ak i ngt hes oundi ngofbunk ert ank s . >  Ev er ys hi pi spr ov i dedwi t hat ankc apac i t yt abl ei nwhi c heac ht ankcapac i t yi n v ol umei smar k edagai ns tt hes uc c es s i v el ev el sofs oundi ng/ ul l agewi t hc or r ec t i on f ac t or sunderv ar i oust r i m andheel c ondi t i onsoft hes hi p.Thev ol umeoff uel oi l at t ankt emper at ur ef ort hec or r es pondi ngt anks oundi ngi st husmeas ur edus i ngt ank c apac i t yt abl e,whi c hgi v est heac t ual s oundedv ol ume. >  Thedens i t yoff uel oi l ( i nk g/ m3)ats t andar dr ef er enc et emper at ur eof15⁰Ci s al way spr ov i dedbyt hes uppl i eri nBunk erDel i v er yNot e.Wi t ht hi st hedens i t yoff uel oi l att an kt emp er a t ur ec a nbede t e r mi ne dus i n gASTM t abl eo ru s i ngs of t war emos t c ommonl yi ns t al l edonal l s hi p’ scomput er . Thef or mul aus edt oc al c ul at et heT emper at ur eCor r ec t edDens i t yi s : =( Dens i t yofFuel Oi l @ 15⁰C)x[ 1-{ ( T15)x0. 00064} ] Wher e: T=t emper at ur eofoi l i nbunk ert ank si ndegr eec el c i us , 0. 00064=Cor r ec t i onf ac t or Si nc et hebunk eroi l i snor mal l ysuppl i edt ot hev es sel att emper at ur ehi gher t hen15⁰C,t hef or mul aus edf orc al c ul at i ngt hebunk erquant i t yi nwei ghtwi l l be-

Me t r i cT o nnes= ( Ac t ual Sou nderVol ume )X( T empe r a t ur eCor r ec t e dDen s i t y ) >  Thec or r es pondi ngv al uesofeac ht ankar et abul at edf oreas yr eadi ngandt he t ot al wei ghtofbunk erquant i t yi scal c ul at ed.

2.Speci ficFuelOi lConsumpt i on( SFOC) : Spec i fi cf uel oi l c ons umpt i oni st hemeas ur eofmas soff uel c ons umedperuni tt i me t opr odu ceperKW.Themar i n een gi n eeffic i en cyi sus ua l l yde t e r mi n edus i n gt he SFOC. I nor dert oac hi ev eac c ur ac y ,t hef uel c ons umpt i onandpowerde v el opedi sal wa y s me as ur edo v eras ui t a bl et i mep er i odonago odwe at he r .Thef o r mul aus edf or c al c ul at i ngSFOCi s : SFOC( g/ kwh)=Massoff uelconsumedperhour/Powerdevel opedi nKW >  Ther e adi ngsoffl o w me t ert omai ne ngi nes h oul db eno t edo v ert h es p ec i fi e dt i me i nt er v al s ay1hour .Wi t ht hedi ff er enc ei nr eadi ngst hev ol umeoff uel c ons umedi s ob t ai n ed.I tc anal s ob eme as ur edbyno t i n gd ownt heHFO s er v i c et a nkr e ad i ng pr ov i dedt heoi l i sbei ngs uppl i edonl yt omai nengi ne. >  Th ema s sofo bs e r v e dv o l u meoff u el c o ns u me dc a nb ed et e r mi n edbyf o l l o wi n g t heabov esai dbunk erc al c ul at i onpr oc edur e. >  Th eh or s ep owe rc a nb eme as u r e du s i n gd y na mo me t e ri ffi t t e do nt h es h af to ft h e engi newhi c hwi l l i ndi c at et heBHPi ndi gi t al i ndi c at or .I fnot ,t hehor s epowerc an al s obec al c ul at edus i ngengi ner pm andav e r agepumpf uel i nde xwi t ht heai dof engi nec har ac t er i s t i ccur v eofv ar i ousseat r i al swhi c hi ssuppl i edbyt he manuf ac t ur er .Howev ert hec al or i fi cv al ueoft hef uel us edf ors eat r i al ma ydi ff erand

henc ec ompens at i onf ac t orhast obede t er mi nedt oobt ai nt heac c ur ac yi n c al c ul at i on.

3.Per c ent a geofSl i p:

Sl i pi scons i der edas

t hedi ff er enc ebet weent hes peedoft heengi neandac t ual s peedoft hes hi p.I ti s al way sc al c ul at edi nper c ent age.Pos i t i v es l i pi si nfl uenc edbyv ar i ousr eas onss uc h asf oul edbot t om orhul l par twhi c hoffer sr es i s t anc et ot hemov ementofs hi p, env i r onment al f ac t or ssuc haswat erc ur r entandwi ndagai ns tt hes hi pdi r ec t i on.Sl i p ma ybenegat i v ei ft hes hi ps peedi si nfl uenc edbyf ol l owi ngs eaorwi nd.Engi nes l i p i scal c ul at eddai l yonboar dt hev es s el andr ec or dedi nl ogbook . En gi n edi s t an ce–Ob se r v e dd i s t anc e Per c ent ageofSl i p=————————————————–X100% Engi nedi s t anc e •

Theac t ual di s t anc e( naut i c al mi l e)c ov er edbyt hes hi pf r om noont onooni s meas ur edus i ngs hi p’ sl og.

•

Thet ot al r ev ol ut i onsoft hepr opel l erf r om noont onooni sobt ai nedus i ng r ev ol ut i onc ount er .Theengi nedi s t anc ec anbec al c ul at edus i ngt hepi t c hof t hepr opel l erpr o vi dedbyt hemanuf ac t ur er .Car emus tbet ak eni nuni t c on v er s i onofpi t c hf r om met ert onaut i c al mi l e( i ngener al 1NM =1800m) .

Engi nedi s t anc ei nnaut i c al mi l e=( Pi t c hxr ev ol ut i onsperday )

Obt ai ni ngt heac cur ac yofv al uei nal l t heabov ec al c ul at i onsar eal way schal l engi ng onboar dast hepar amet er sr ec or dedar emor es ens i t i v et ody nami cc ondi t i onsoft he s hi pandal s odependsonv ar i ousenv i r onment al f ac t or s . Ov e rt oy ou … Doy ouk nowanyot heri mpor t antc al c ul at i ont hatc anbeaddedt ot hi sl i s t ? L etu sk n o wi nt h ec o mme nt sb e l o w. Ref er ences& I mageCr edi t s: M. V.J agRah ul –Shi p’ st a nkc ap ac i t ypl a nma nual . M. T.JagPr eet i –MI TSUIB&W –Oper at i on&Dat aManual ReedsNa v al Ar c hi t ec t ur ef orMar i neengi neer s .