LNG Value Chain – An Introduction to LNG, being as the alternative of a (relatively) clean energy for marine fuel

 

By Agung Aang on Friday, June 24^th, 2011, at 03.45 PM

The Natural Gas, known as “Methane” is believed to be one of the alternative energy beside other fossil energy, that is known to be relatively clean and cheap. It’s relatively clean compare to the other sources of energy such as fuel oil, coal, etc due to methane having less carbon chain compare to others, thus in the combustion process, will produce and release less carbon emission to the atmosphere. That’s why it’s good and safer for the environment.

It’s also relatively cheap since it is believed that the global reserved is still at the sufficient level compare to the other fossil energy that had led to the scarcity all around the world. However the development of the application that uses and consumes Natural gas is still limited nowadays, especially in some third world countries (including Indonesia I guessed). In some modern countries, we saw that the people’s access in to this type of energy had been indulged since last decade.

There are at least two type of technologies (processing & containment) to deliver the Natural gas (Methane) to the customers / end-users, which first is LNG (Liquefied Natural Gas) and second is CNG (Compressed Natural Gas), this time I will start to elaborate further on LNG, we can do The CNG at some other time.

Anyway to get to know further in to this LNG thing, one has to understand first the characteristic of the LNG it self. LNG is the natural gas that has been liquefied by being cooled (thru a thermal process cooling) in to an approximately -160°C (-260°F). LNG ~ 1/600 volume of Natural Gas, making it practical to transport by ship, Can be stored and transported in insulated tanks at standard atmospheric pressure. Flammable when mixed with air concentrations between 5% - 15% (methane). Not generally considered as an explosive.

The LNG Value chain from the source fields / gas well in to the end-user are described as per-herewith diagram

 

            

As obviously seen, Natural gas which was produced from gas well, brought up through gas pipelines in to The Processing Plant where gas were liquefied and keep in liquid forms for further shipment process via an export Terminal. As earlier mentioned, gas volume in liquid faction is 1/600 times of it’s volume in original gas form, making it more practical and easier to handle during transport.

Then an LNGC will bring the gas, in liquid forms (LNG), which were kept onboard within an enclosed/insulated cryogenic containment from the Export Terminal in to the Import / Receiving Terminal, where the LNG is discharged / un-loaded in to storage and another Processing Plant, called Re-gasification Plant, where the liquefied gasses is changed back in to the gas forms before it’s virtually delivered and further distributed in to the end-users (i.e power plant, industries, etc) through gas pipeline facility.

There are at least two (2) types of The LNG Receiving Terminals being developed recently, first is On-Shore based Terminal where the Storage and Processing (Re-Gasification) Plant were located on-shore, and second is Off-Shore Terminal where the Storage and processing (Re-Gasification) Plant were located Off-Shore, it could be in a form / module of Floating Storage and Re-Gasification Plant (FSRU Barges or Vessels) and or Fixed Permanent Floating Terminal (using Gravity based, piled/fixed platforms, etc)

There are off course several pros and cons between these 2 types of Terminals, however peoples tend to explore more on the Off-Shore types recently due on the following reasons i.e. almost no land-acquisition involved (considering potential social risks), relatively faster to build, relatively less capital investment, less complex permit as well as the most issues on the mobility idea.

The most issues involved in this choice is it’s high sensitivity to the weather changes, especially rough se-condition.

Before coming to the development and application of the LNG for Marine Fuel on the next parts, to close this chapter, author would like to express his deep concern on, as of date there are none of such kind of Receiving (Import) Terminals were ever built and developed for and within Indonesia. Without any of such infrastructure made available, no wonder if the Natural Gas utility within Indonesian people in general is still low compare to other developing countries. What has become sad contradiction is, Indonesia as one of the world biggest Natural Gas Producers, sell it’s Natural gas for cheap to other countries, where it’s own Indonesian people does not have sufficient access to also enjoy the benefit of Natural Gas due to lack of (receiving) infrastructures made available.

Really sad…

End-June 2011

Sinopsis Running Cost Pengoperasian Kapal - Terms for dummies II

 

by Agung Aang on Thursday, June 23rd, 2011 at 2:45pm

Seperti yang sudah disampaikan pada tulisan di Bag.I terdahulu (i.e.Sinopsis Running Cost Pengoperasian Kapal – Term for dummies I) istilah Running Cost dalam pengoperasian kapal, adalah bagian dari komponen biaya OPEX (Biaya total pengoperasian Kapal), diluar komponen biaya Voyage yang harus ditanggung oleh pihak Owner/Operator kapal pada waktu mengoperasikan kapal-kapal armada mereka.

Jika pada tulisan terdahulu sudah disampaikan secara detail kelompok-kelompok biaya apa saja yang masuk ke dalam kategori komponen biaya ini, maka pada tulisan kali ini penulis akan mengajak untuk melihat besaran kontribusi dari masing-masing kelompok biaya tersebut beserta proporsionalitasnya terhadap keseluruhan biaya Running Cost pengoperasian kapal.

Kita tahu bahwa Komponen Biaya Running Cost itu terdiri dari kelompok-kelompok biaya Manning (Crewing), Technical (M&R, Supplies, Stores, etc), Insurance (H&M dan P&I), General Administration & Others. Pertanyaan selanjutnya adalah seberapa besar-kah kontribusi dalam persen (%) dari masing-masing kelompok biaya tersebut terhadap keseluruhan Biaya Running Cost kapal? Bagaimana juga proporsionalitas dari masing-masing kelompok biaya tersebut terhadap keseluruhan Biaya Running Cost dari berbagai jenis dan type kapal dan operasionalnya?

Sebagai langkah awal penulis akan mengajak melihat gambaran breakdown detail kelompok biaya Running Cost dari berbagai jenis dan type kapal sebgaimana tertuang dalam tabel riset yang dipublikasikan oleh lembaga riset pasar Drewry seperti tersebut di bawah ini.

                  

Jika dicermati lebih jauh tabel tersebut, besaran dari masing-masing kelompok biaya pada setiap jenis dan type kapal akan sangat bervariasi, namun demikian akan dapat terlihat pola yang hampir sama terjadi pada besaran kontribusi dari masing-masing kelompok biaya tersebut terhadap komponen biaya Running Cost keseluruhan pada setiap jenis dan type kapal yang berbeda.

Hal ini menarik untuk dicermati lebih jauh karena dari sejauh pengalaman penulis selama ini mengelola biaya running cost dari berbagai jenis dan type kapal, memang diyakini adanya suatu pola yang sifatnya umum (kurang-lebih berlaku untuk semua jenis dan type kapal) yakni pada besaran kontribusi dari masing-masing kelompok biaya di atas terhadap total komponen biaya running cost (secara keseluruhan) kapal.

Dari hasil telaah dan kajian penulis selama ini, pada umumnya akan terlihat pola distribusi kontribusi sebagaimana terlihat di bawah ini;

 

                  

 

Dari sana terlihat bahwa terdapat 2 kelompok biaya utama yang selama ini mendominasi kontribusi terhadap total komponen biaya running cost kapal yakni kelompok biaya untuk Crew / Manning dan kelompok biaya Insurance (pembayaran premi H&M dan juga P&I), kedua kelompok biaya ini mendominasi kurang lebih dua pertiga dari total biaya running cost keseluruhan.

Bahkan kelompok biaya Technical (terdiri dari biaya-biaya maintenance, repair, service, supplies, stores, dll) yang selama ini dianggap paling bertanggung jawab terhadap naik-turunnya pemakaian biaya running cost kapal hanya berkontribusi kurang dari sepertiga total biaya running cost secara keseluruhan. Kebanyakan orang akan selalu berfikir bahwa untuk mengontrol ketat pemakaian anggaran biaya running cost harus dilakukan terhadap realisasi penggunaan anggaran biaya MRS (maintenance, repair dan supply). Solah-olah kelompok biaya ini senantiasa melekat dan terasosiasi kepada pelaksanaan program efisiensi dan pengetatan / pengontrolan anggaran selama ini.

Hal tersebut terjadi tentunya bukan karena tanpa sebab-sebab tertentu, salah satunya adalah karena sifat dan nature pengeluaran / realisasi expense-nya yang cenderung merata sepanjang kurun waktu anggaran, akan sangat berbeda dengan misalnya sifat pengeluaran kelompok biaya Insurance, i.e. pembayaran premi yang hanya terjadi sekali dalam satu periode anggaran. Dan tentunya juga karena kecenderungan kita melihat kelompok biaya MRS (Technical) sebagai satu-satunya kelompok biaya yang paling memungkinkan untuk dilakukannya penyesuaian kapan-pun di sepanjang paruh waktu periode anggaran, akan berbeda kasusnya jika kita bandingkan dengan biaya wages (gaji crew), yang terikat oleh kontrak perjanjian sehingga tidak dimungkinkan terjadinya perubahan pada setiap saat.

Untuk itu penulis mengajak pembaca untuk kembali berfikir dan melihat secara logis dan proporsional pada saat akan melaksanakan program pengawasan dan pengetatan (efisiensi) anggaran, bukankah sesuai pendekatan PARETO kita harus memulai dari sebagian kecil hal yang membawa pengaruh ke sebagian besar hal?

Adalah wajar jika kita diharuskan untuk melakukan pengetatan / pengontrolan secara ketat realisasi pengeluaran pada pos anggaran running cost, kita mulai dari 2 kelompok biaya utama yang berpengaruh (berkontribusi) paling besar tersebut, yakni kelompok biaya Manning dan juga kelompok biaya Insurances.

Demikian sharing kali ini, semoga bermanfaat…ammien.

End of June 2011

Ship New Building, how to define fair Price? How does cost distribution of a given Price look like?

By Agung Aang on Tuesday, June 14^th, 2011, at 02.02 PM

How to judge the fairness of a given New Building Price of (for example) a 6,000 DWT single Decker double hull, double bottom General Cargo vessel with IACS Class Notation for Ocean going? or New Building price for a 5,000 DWT double hull, double bottom, IMO Type I/II Oil & Chemical tanker, with IACS notation for coastal service, built locally?
To be able to do so, one has to know exactly what factors could drive the Shipyard/Shipbuilder to come up with a certain selling price for New Building construction. There are at least 2 main factors that might influence The Shipyard/Shipbuilder in defining their best quoted price for New Building in a given time.
First and foremost is The External factors, factors which are beyond their power to control, such as;
- Supply & demand situation in the market, sometime is The Builder/Seller market but some other time is a Buyer market.
- New Rules & Regulation applied, i.e. by Class, IMO, Statutory, Local Government, etc
- Steel and other commodities price level, even though some attempts could be afforded by The Shipyard to peg or hedging the price, still on some certain extends it’s beyond their competence to keep.
- Global Energy price level
- Currency exchange & borrowing rates level
- Old Tonnages phasing out rate & Scrap value rate
- Taxation scheme, etc

Secondly is The Internal factors, factors which are still within their competence to control, those are including but not limited to as follows;
- How good they manage their production cost level to stay efficient and competitive.
- How good their production system is, to maintain schedule & production phase.
- How good their project management is, one right time and one time right, right in time without fail & repetition.
- How good they manage their overhead allocation for the project.
- How good they raise and manage their project financing
- How good they manage the project risk, etc

On Shipyard / Shipbuilder’s perspective, New Building Project is normally having relatively less return compare to any Repair & Conversion Project. Thus the profit expectation for a New Building project is quite marginal compare to other project types. One of the reason is just because of the New Building project is typically having longer turn around time, hence the cost of fund is very much involved through out the project period of time.
What are the major groups of production cost, of a New Building Project, and how are they well distributed in forming a given New Building price?
The figure below is showing the distribution pattern of each group of The Production costs of a new Building project that drive the Price.

               

* The figure is extracted merely from the author’s extended experiences in handling New Building Projects both at Shipyard perspective’s end as well as Owner perspective’s end. Wisely it shall be treated as guidance only, the exact and actual percentages of each might be vary on every certain specific projects.


Where the detailed of each (in the order of the biggest portion) are as follows;
- Machinery Group, in the region of 40% up to 45% – consist of all costs incurred to procure and install all the machineries and systems onboard i.e. main propulsion system, main engines, auxiliaries engines, boilers, pumps, compressors, gearbox, shafting, steering system, heat exchangers, etc
- Hull Part Group, in the region of 35% up to 40% – consist of all costs incurred to procure and fabricate all the Ship’s Hull and Deck Dept onboard i.e. Hull steel construction, rudder construction, mooring system, life saving appliances, deck piping, cargo handling systems, accommodation, coating, etc
- Electrical Group, in the region of 7% up to 10% – consist of all cost incurred to procure and install all the electrical system onboard i.e. radio communication systems, radar systems, satellite communication system, cabling, lighting, Navigation system, etc
- Fitting & Installation Group, in the region of 7% up to 10% – consist of all cost for Labor, workmanship, handling facility, etc
- Design & Class cost, in the region of 3% up to 5% – consist of all cost incurred to procure Ship’s design, Class survey & inspection service, Class Plan approvals, testing, trials & commissioning, etc
- Other miscellaneous Group, in the region of 2% up to 3% – consist of all cost incurred for the Project’s cost of fund, ceremonial, etc
The above mentioned distribution pattern, in general is likely and widely applicable to the new building of all types of vessels / ships, be it General cargo, tankers, break bulkers, bulkers, supply vessels, etc, should there be variety on the portions/percentages of each groups, let say on a particular case of the new building of a specific types of vessel i.e. FSO, FPSO, FSRU, DSV, and or other Offshore support vessels, etc, believed it won’t change the main pattern in a whole.

It’s obviously seen from such pattern, that the 2 most contributing groups are Hull and machinery, where both are contributing total 75% of the Ship’s New Building Price, these are the areas that contributing most to the New Building price. In fact the Design and Class only less contributing compare to the others, all together only less than 5% contribution to the Price.

Last but not least, by understanding the pattern well, hopefully we can have a better basis for evaluation and eventually judgment of the fairness of the Ship’s New Building Price given by any Shipyard.

June 2011

Shipping Business in General – Terms for dummies I

By Agung Aang on Monday, June 13^th, 2011, at 01.42 PM
Some may ever think that shipping is such a complex world having so many terms, which some are really confusing and some time conflicting each other, the idea of serving this Note is to help one to understand better The General Shipping terms in a much easy way.
The basic economic motive of shipping is providing service to deliver/transport goods from one point of pick up (point of origin) to the point of delivery (destination point), involving two main parties i.e. The Shipper, in this case is the owner of the goods (cargo) as well as The Carrier, The one who virtually delivers the goods (cargo) to the destination, in this case is The Ship’s Owner/Operator. There are several ways of shipment i.e. Air-freight, Sea-freight and Land based-freight (trucking, train, etc). This note will serve to elaborate more on the Sea-freight, even though some basic principles might be similar and also applicable for the other 2 shipment ways.
There are two main types of Shipping, first is Liner Shipping, where sailing time is scheduled and freight rates are based on certain standard tariff, mostly for passenger, general cargoes and containers. The second one is Tramp Shipping, where sailing time is not scheduled; freight rates are negotiated and formed individually, type of cargo might be vary from general cargoes up to specific industrial cargo such as chemicals, oil & gas, coal, and other project cargoes.
In term of operating / running a Ship in the Shipping business, herewith are several basic/major shipping contract types (Charter parties), commonly used and quite popular in the market, complete with each explanations as;
- Voyage charter - It is a contract between Ship owner and charterer for transportation of a specified amount of commodity from loading port to a destination, where The Ship Owner is responsible for all the cost incurred. Normally rates are sets on a Dollar per-Ton basis of cargoes carried (Dollar per-unit cargo weight carried)
- Contract of Affreightment (CoA) -  It is a contract between Ship Owner and charterer for transportation of a specified amount of commodity from loading port to a destination over a certain agreed period of time (i.e. 1 – 2 years) where The Ship Owner is responsible for all the cost incurred. Normally rates are sets on a Dollar per-Ton basis of cargoes carried (Dollar per-unit cargo weight carried)
- Trip / Tramp Charter – The contract which set and only valid for one Trip, where The Charterer is responsible for all the Voyage Costs incurred such as fuel-bunker cost, fresh water cost, ports & agency costs, etc. Freight rates are normally set on the basis of Dollar per-day throughout the no of day’s charter.
- Time Charter (T/C) - Charterer hires the vessel for a specified period of time and takes the commercial control over the vessel, where The Ship Owner is responsible for operation and capital costs, whilst Charterer is responsible for all the voyage costs. Rates are normally set on a Dollar per-day basis throughout the days of the charter period.
- Bareboat Charter - Charterer hires the vessel for a very long (specified) time, normally the whole economic life of the vessel, where Ship Owner is responsible for the capital cost only, and Charterer is responsible for all other costs. Rates are normally set on Dollar per-day basis throughout the days of the charter period. Used to be quite popular on the Energy sector market.
Along the way, some other types of lately developed contract/charter are also introduced in to the market, thus basically are the latest developed / modified version of the above mention basic types i.e.;
- Back – to – back Charter – Basically is a modified type/version of a T/C contract where the Ship owner deals with the Charterer through someone else’s, upon an agreed marginal fee’s.
- Modified Bareboat Charter – Basically is a modified type/version of a Bareboat Charter where The Ship Owner is not only responsible for the capital cost, but also some other Operational Cost (Opex) i.e. crewing cost, P&I Insurance, H&M Insurance, etc
Diagram as shown below will show the detailed flows of thought on Ship owner’s perspective with regard to the split up responsibilities and cost sharing composition amongst several types of basic contract that the ship might have upon its operation.
                   
*Figure diagrams taken from one of slide presentation from Navigate Consulting, June 2008
Thus obviously seen the distinction amongst several areas of shipping businesses over Owning, Running and Operating a Ship or a fleet of ships, complete with each borne cost responsibilities.
That’s all what I can share on this first chapter, hopefully it could be useful and come of your help in understanding better the basic of shipping business. Insya’Allah will continue with Ship Asset Procurement & Selection on the next chapter, on some other time.
June, 2011

Pelajaran Ikhlas

by Agung Aang on Wednesday, October 14, 2009 at 3:59pm

...Sesosok tubuh tua berbalut seragam Polri dng pangkat Bharatu (klo ga salah), dng rambut yg agak memutih berdiri di tengah terik matahari di sebuah perempatan padat slipi, ditengah sibuknya mengatur kepadatan kendaraan yg berseliweran, meski keringat & peluh membanjir diwajahnya yg tua, tiada sedetik-pun senyum ramah menghilang dr wajahnya yg capek itu, sembari selalu menganggukkan kepala hormat kpd setiap orang yg lewat.SUBHANALLAH...bahkan hati yg membatu sekalipun akan dengan penuh kesadaran & keikhlasan memberikan senyum balasan...mmhhh satu lagi guru Ikhlas Kau hadirkan didepan mataku, Alhamdulillah:)

Ah...senyum itu serasa sdh ckp memberiku kepastian bahwa tiada sempat terpikir oleh sang pemilik senyum, jangankan pamrih dan pengharapan atas materi atau sekedar penghormatan, bahkan pahala atas kebajikan sekalipun tidak...karena senyum itu sendiri, speak for it self bahwa dia hadir sbg bentuk manifest dr satu kekuatan yg lahir dr hati ...yg kadang terasa absurd...bgmn ga absurd...panas2, berdebu, capek melaksanakan tugas dan kewajiban yg imbalannya gak seberapa dibanding resiko dan pengorbanannya, masih ditambah lagi kadang dicuekin, dianggap gila, termasuk jg disumpahin pemakai jalan yg merasa terganggu...tp msh jg mampu memberi dan menunjukkan satu bentuk rasa syukur, menerima dan menikmati, atas segala apa yang menjadi bagiannya untuk melaksanakannya dan menyerahkan sepenuhnya segala sesuatu sisanya yg bukan bagiannya kepada Allah untuk melaksanakannya.

Bagi mereka memanjatkan doa dan melaksanakan doa adalah bagian dr manusia dan selebihnya (mengabulkan doa) adalah bagian dr Allah sepenuhnya. Senyum itu cukup bercerita untuk itu, bahwa...buat pak polisi tua itu pengorbanan dalam melaksanakan tugasnya yg mulia adalah bentuk pelaksanaan dari doa2 nya yg selalu ia panjatkan kpd Allah, sedangkan dia tidak mengharapkan balasan apapun atas apa yg sdh dia lakukan atas doanya karena itu sdh menjadi bagian yg bukan lg menjadi bagiannya untuk melaksanakan.

Sungguh memang terasa absurd kekuatan/makhluk yg bernama ikhlas itu...tp sangat indah dan powerfull bagi manusia yg selalu berharap akan Ridhlo-Nya...wallahu a'lam bishawab

...Luruha galihe kangkung
...mibero koyo tapak kunthul miber
...nuliso tanpa tulisan ing papan tanpa tulisan
...kowe bakale ketemu...ning...nang...nung
...bening...tenang...dunung

Oct 2009

An Approx approach of Tonnage(GT)measurement of a Trading Vessel,as an alt instant way to calculate Ship's Tonna

by Agung Aang on Friday, March 20, 2009 at 11:49am

Not like my previous note, this time I would be more careful in using term in referring to someone else…especially if the one is my own Boss…he..he..he…easy Boss…peace!

Ok, again non alike to my previous note, this time I would share material that I refers to one of published book with the title of 'Naval Architecture', indeed it's a marvelous book, small book with hard cover, unfortunately I forgot exactly the author as well as the publisher of the book (since the book has recently missing somewhere) for me the book has truly like a Naval Arch pocket book for the dummies, it's very much powerful.

I referring to one of the magic formula written within the book, the formula is a lot simple and easy to remember, but in fact its quite powerful. The formula is used to calculate instantly the Gross Tonnage (GT) figure of the Trading vessels. Talking about the Gross Tonnage (GT) figure it self, for sure you'll need this figure for various purposes, one out of it is when you are about to calculate the feasibility study of buying a second hand trading vessel and later assign and or operate the vessel for a specific project. Some of the information that you might need to structure up your project costing, are a lot related to this (GT) no, those are as listed as follows;
a. In order to get some indicative of P&I premium rate figure, both for advance and supplementary call, you will need the information of the GT of the vessel going to be applied.
b. In order to get some indicative on the berthing fee (cost) of the vessel, you will also need this GT no of the vessel.
c. Some of the various Port services fee were also based on this GT no of the vessel, i.e. Assisting Tugs fee, calling / clearance fees, Mooring fee, Immigration, Port health & quarantine (if any), etc, thus are applicable for both domestic ports and or international ports.
d. The agency fee of the vessel it self on each calling Ports are also based on this GT no of the vessel.
e. Canal passing fees are also based on this (GT) no, even though each canal i.e. Suez, Panama, etc, has their each own way in defining and determining vessel's tonnage which are differs one in to others.(however the result may vary with an average minim deviation, hence as general reference IMHO we could use still this approach )
f. etc

As aforementioned, in a certain situation where you are only about to purchase a second hand trading vessel, where in this case you do not have yet a full access toward vessel's information, you would have no other choice but to calculate your own the vessel's approximately GT No's, otherwise you might not be able to complete your desk top investment study (FS) due to lack of above mentioned cost information.

Further on, in fact as far as I noticed so far, the information of vessel's GT was very seldom to be stated and mentioned within Vessel's short specs that is stipulated within Broker's Firmed Offer. Hence to be able to proceed further with your S&P plan you will have to find and calculate your own (self predict and indicate) other missing information that you need for instant GT No.

The instant magic formula is GT (T) = (L x B x D)/125

- Where L is LBP of the vessel in Ft, whilst B is Beam molded of the vessel in Ft, and D is the Depth molded of the vessel also in Ft
- In some occasion where LBP information is not mentioned, I used to use any Length (since the result would not much different, this is such an estimated figures anyway).
- Please do not mass up the units, the formula works in British Unit instead of Metric

Though it is not a long and confused formula to remember don't you? Good luck, hopes it could be helpful for all of you…ammiieen Ya Rabb Alamin.

March '09

An Empirical predictive on fuel consumption figures per-day(T)of old timer Tug Boats,i.e.Tot.Hp X 4;where does it come fro

by Agung Aang on Thursday, March 19, 2009 at 11:01am

May be some of you have ever heard the above mentioned "rule of thumbs", claimed by our beloved old geeks Marine Engineers (those who sailed onboard Tug Boats & Utilities in the early 70's to 80's). Indeed it's not a kind of Axioms nor Law's resulted from a series of published research and iteration, however in fact the said predictive formulas as a rough based calculation (ball park figure)is quite powerful to get some indicative figure instantly, even for nowadays context.

I had notice myself that I have got the same methods of prediction at least from 5 different engineers who sailed during such type of vessels within such above mentioned period of time (70's to 80's)

I myself so used to utilize it frequently in certain situation where I've got to be answerable to my boss on the issues related to fuel consumption figure within short seconds, otherwise I might got another "Jancuk" if I failed to give an answer instantly.

After some times, I just eventually realized that the nos produced from that numerical operation, was actually not that bad, from my record analysis done very recently, I found that from various size Tug Boats (some also utility vessels), with conventional hull bodies, single screw, single engines, in between 5 to 15 years old built, from various brand of propulsion engines as long as high speed diesels, and irrespective of the applied ratings, after I ran an iteration with a norm distribution, the error margin was only within the range of 4 - 7 % (amazing huh?). Though it is enough for me for such an estimating (rough prediction)purposes only. Even though I found this very much interesting however, yet, I will not dare to test this hypothesis further in to a certain further stage of a scientific research methodology, please I'm not a scientist, it is merely on my curiosity, I do not see it falls within my areas of interest (may be some of you does?), Further on I believed that it is just a purely practitioner's approach, not more not less.

After I ran through further the numbers, I've found another fact that the error nos will increased significantly, it goes up to 10% and over, for the application toward a twin screw-twin engines Tugs, as well as for non conventional hulls (modified bow's hulls, modified flared hulls, etc), it goes between 8% - 10%. Hence ones got to be careful to apply such formula for these kind of configurations. Unfortunately I do not have an ample time to see further correlation of the nos for the application of Z-peller drive (an azimuth thruster), I'd just do not have time. All the above mentioned nos are for the application of conventional thrusters with protruded tail shafts.

Before steps further on our discussion i.e. How and where does it (the formula) come from? In order to avoid any false information, I'd like to re-highlighted that the consumption nos meant was the actual daily consumption figures after the vessels put in operation after some time and not the theoretical nor the designed nos, please take a note on this, after all these are more relevant for practitioner.

Even though the formula did not meant for theoretical consumption figures , in order to trace where does that formula come from I would use still a theoretical approaches, as you might aware, the normal daily consumption figure could be obtained from the formulas of SFOC (gr) x BHp (cont) x 24 (hr), from which we could then understand that in order to get in line with the above predictive formulas, the range of the SFOC in a certain assumption of 85% MCR (or even less) of the engine, should be at least abt.195 - 200 gr/BHp/Hr, which is true from a serial of High speed diesel engines in the output range of 750 - 2000 Hp, the SFOC was in the range of 203 - 213 gr/BHp/Hr.

In spite of various and volatile rpm applied through out the operational regime of a Tug boat, an average no of 75 - 85% MCR of engine performance during long distance voyage (more than day) continuously, is found to be quite representatives and does make senses. Thus we could use it as basis for the average actual daily fuel consumption as aforementioned.

Irrespective of all scientific proofing methodology 'IMHO' we can use the formula still, especially on a certain situation where we have to be able to get an instant idea on a predictive consumption figure of a running Tug boats or other Utility vessels, maybe on a certain situation where your boss asking you to get the answer within minutes while at the same he pointing out a gun tip over your head…then I just strongly recommend you to apply the formula…he..he..he…after all again this is just a rough predictive approaches, therefore DO NOT TRY THIS AT HOME…!

March '09