Trimming Operation
Dear Juliancw,
The following response is from the ship operations viewpoint and may solve your problem without need for any investment in real estate or equipment.
Normally Iron Ore is loaded on a Free In Spout Trimmed basis, with shippers / charterers responsible for time and cost of trimming as stipulated in the charter party.
Prior to arrival & commencement of loading, the shipper is entitled to request the vessel master to make a written cargo quantity loading declaration to enable the shipper to prepare the correct amount of cargo. The master would declare the cargo quantity with his safe draft and trim in mind. The master should also be asked to present his holdwise stowage plan and preferred hatchwise loading sequence, which he would advise after considering the stated loading rate per hour ex spout and the calculated stresses on the vessel. Towards the end of loading the master would likely request to slow down or stop the conveyor for a short time in order to check his drafts and exactly calculate and then would instruct to load the balance say 3,000 - 5,000T of cargo in specific hatches to acheive his desired trim. There should be no question of him demanding extra cargo at that stage in excess of his declared quantity and if his trim is still not in order and he has to ballast then it would be his problem.
In my opinion the matter of trimming can be sorted out by the correct operational procedures which could be elaborated on by your loading master at the berth and by issuing written SOP's in your shipping terms. It should not be necessary to have additional cargo in trim bins etc if the declared cargo quantity is already on the conveyor. There would be no need to offer to pay deadfreight for ballasting. The only problem that may arise is if the master makes a misdeclaration and requests too much cargo, in which case you could hold the master / vessel responsible for costs of handling the excess. Hope that may assist you in your deliberations.
Best Regards
Kassim Gokal
eastasiamaritime@singnet.com.sg ■
Re: Avoiding Trim On Vloc
Hello Juliancw.
You have asked very interesting question. You are not alone with your problem. There are many terminals, who have fast loading rate and only one shiploader, faced with such problem. There is no one exact solution to completely avoid or bypass this “problem” because ship’s trimming it is normal and, usually, compulsory loading procedure, if you know this procedure included in “ship-shore checklist” and have to be discussed on ship arrival before loading commence.
But of course there are some ways to minimize the losses from this procedure. To find the best solution for you, you have to specify many other things, such as:
Will you operate only as transshipment terminal or as shipper or charterer too?
How you will determine the weight loaded, if it will weighing feeder, where it located?
What is your actual depth at the pier?
Do you have port’s draught restriction or will you load up to ship maximum draught?
How many loaders can be used for loading of one ship, if more then one, have they one ore separate delivering conveyors?
And many other questions. But first of all, you have to determine what you want to minimize: the laytime or the time of pier occupation by the ship. Both of them can be considered as downtime, but requires a beat different approach to resolve.
If you need to reduce the laytime, you can add to the charter party next clause: “The time of trimming procedures will excluded from laytime”. Then, just ship officer will stop you for check the draught, make some calculation etc, you must write in statement of facts: “Loading suspended by ship administration. Trimming operations commenced.” We always do like this, and it always work. Even if you represent only loading terminal, you hare a right to insist on it, because it mostly depends on master’s or chief officer’s competency.
If you need to free the berth quickly because of the queue of other vessels, you can pay dead fright of course, but I don’t think that is the best solution if you are talking abt 3000 MT. By the way trimming by such amount of ballast will require almost same time. But in most cases, I don’t see the reason to pump in the ballast if ship is not loaded completely.
About prior information from master regarding quantity to load. If you will only ask ship haw much they can load, they will always give you information with remark like this: “This is preliminary information. The actual quantity will depends on actual water density, ship’s fuel and stores quantity,……..”. By this they will protect themselves from responsibility on quantity. If you have to prepare cargo to load previously, I would advise to put in charter party fixed quantity, which is near to pre-advised by ship but can be guaranteed by both sides. In this case ship will not able to claim dead freight.
And finally, how to reduce the time of trimming operations if you required to do so. It will completely depend on skills of both ship and shore persons responsible for loading. You shouldn’t rely on preliminary quantity if you want to complete your loading quickly. When abt 70% of cargo will on board, you have to start recalculate the quantity remain to load according to actual draught and water density, not stopping the loading. You have to do it time to time and more often as loading approach to completion. You must to know the accurate quantity hold by conveyor, and you must advise the ship’s officer about this, don’t try to lie as many terminals do, usually it creates only problems. It will be better if your representative will participate in all calculation stages, just then he will get full control under entire loading process. It is good to have computer assistance program for ship trimming. I don’t know why certified programs for loading calculation very seldom have this option, maybe because trimming time it’s problem of terminals and ship operators don’t care about this but, anyway many chief officers and port load masters have it’s own programs that helps them to significantly reduce downtime while final trimming operations.
That’s all for now. But I think the answer would be shorter and more certain if you gave more information or made more specific question.
Best regards,
Vladimir. ■
Re: Avoiding Trim On Vloc
Julian,
Please give Vladimir some more information so that we can keep him on a roll. He's a joy to read.
Kassim was also superb with his answer.
For this landlubber's tuppence worth. It might help if you had a return mechanism at the end of the wharf conveyor. ie put a fixed tripper at the end to discharge, down & under, onto the return strand. That would start a return route for unwanted committed ore.
Don't forget the trim bins might have to be cleaned out if there is a different requirement for the waiting vessel. Or you need a whole mess of bins. ■
John Gateley johngateley@hotmail.com www.the-credible-bulk.com
Avoiding Trim On Vloc
Dear Julian
Agrico Sales, Inc. (www.agricosales.com) manufactures a shiploader that solves the problem to trimming. Our shiploader features 2-4 fixed towers with 38 to 45m rotating and shuttling booms. Any one boom can deliver the full flow to the ship. By using a proportional valve under the feed conveyor from shore, you can split the flow allowing one shiploader to flow 95% of the full flow while another shiploader trims at 5% of the full flow. Of course, this can be adjusted for any ratio of split.
Another typical delay is during berthing the ship, draft surveys, customs etc. The same shiploader can be swung around to load on the other side of the dock while this is going on.
The fixed foundations (dolphins) are also much cheaper than a full dock for a moving shiploader (see pictures on our website).
With a little more info we can give you a no cost budget quote in a few days.
Best regards,
Frank Kelly ■
Untitled
Hi all, thanks for your advice, it is very helpful.
More detail here for you to ponder as this is still at the conceptual stage of the project and we have been told trim bins are now not an option at all, so we have to find a solution that will reduce or remove the need for trim on a VLOC. There is more data below so you have more detail of the future development.
The Wharf would be around 6km off the coast in a cyclone belt. We would be a shipper, and we are looking to build one of the largest wharf structures in the world that would have a 6km trestle and then a wharf 1.6km long (if you know of any similar port that has this same or similar length please let me know so we can visit it?) The wharf deck would be up to 23m high and accommodate 8 VLOC of around 330000DWT; however, we may go down to 250000DWT once we have done more research. We would install 4 shiploaders with a 14000tph load rate so would average 8000 to 10000tph in line with the BLU code so we don’t overstress a ship and we have extra loading capacity for future if required.
The stockpiles could be over 16km away from the wharf trestle. If a ship was at the end of the berth it would take ore some 87min to travel this distance of around 21Km traveling at 4m per sec, which is why we were looked at trim bins. The belt itself could hold as much as 13000t of ore. We would ship between 3 and 5 products from this area so the trim bins became a very costly device when built in this area for so many products which is why we are now looking at removing trimming pours from the operation. Given the huge delay to put 1000t of cargo on a belt in multiple holds the dead freight costs seem minor compared with lost production times. We would expect to ship 200mtpa from this terminal and more if we can reduce delays.
Quote: How you will determine the weight loaded, if it will weighing feeder, where it located?
We have several Weightometres that would be installed along the length of the wharf (may have 2 or 3 for accurate calibration). These would be installed well away from the shiploaders due to the movement of the belts when close to the shiploader causing errors. The shiploader would
Quote: What is your actual depth at the pier?
The berth pocket would be around 21.5m deep and the departure channel around 15m with a tidal range of between 1 and 7m but average of 4m. As such we could load most ships to around 18.00 to 19m and deeper on occasions during spring tides.
Quote: Do you have port’s draught restriction or will you load up to ship maximum draught?
We work normally off a guaranteed draft but 1/3rd of all ships take more cargo if available down to the summer marks dependent on the disport. We would be restricted in some circumstances but would be interested to know if dredging the departure channel deeper would allow you to sail ships without the trim so they can ballast down if required. The question is how much would you need to light load a ship so they can do this?
Quote: How many loaders can be used for loading of one ship, if more then one, have they one ore separate delivering conveyors?
We will configure the wharf so we could dual load using traveling shiploaders if needed once deballasting on the ship is completed or if a wharf area is under maintenance. Normally you would load one side of the wharf and then once loading is completed slew across to the other side. If trim can be removed we would save several hours of downtime per ship given the length of the wharf. I noted the comment that you could stop loading or do running draft checks several hours out. Then load on the rest with the ship knowing this is all he is going to get. The ship could then ballast down for even trim prior to departure. I would be interested in others thoughts about this as well.
Quote: But first of all, you have to determine what you want to minimize: the laytime or the time of pier occupation by the ship. Both of them can be considered as downtime, but requires a beat different approach to resolve.
What we want to do is continue to load ships as the ships maximum safe loading rate so we maximise outloading capacity at all time. When you stop for trim these rates drop off and over this distance we would like to remove these as simply as possible.
Hi Agrico: I had a look at your web site but splitting of ore is not feasible as we are basing the design on one traveling shiploader. When completed loading they would slew around to the next ship and load at maximum rates as such the 5% would only be loaded if we had another shiploader on the adjacent berth. The whole point here is to maximise output at all times. The only time the shiploader would stop is during hatch changes and trim at the moment. We cannot remove hatch changes (we can minimise them if safe) but we could reduce or remove trim if possible. The issue is how you could do this so as to maximise tonnes loaded onto each ship while still allowing ships to sail in a restricted channel.
We have about 30hrs or 3 tides to sail and berth ships on alternate sides of the wharf so this gives ships time to pump on ballast if required while loading constantly at faster rates. If we stop for 1 hour we would loose around 10000t of capacity.
I hope this paints a better picture of the future operation. Hope to hear more from everyone with this information and thanks for all of your valuable responses, I have added 8 things onto my list I hadn’t even thought of so far. ■
Trimming Vloc
Dear Julian,
Looking at the scale of the operation proposed, I can see where you are coming from in trying to reduce the trimming time and in turn maximise the terminal output.
However as clearly described in Vladimir's response, trimming requirements are much dependant on the particular demands of the ships staff, mainly due to their responsibility of safety at sea.
Your system / SOP should therefore be designed to minimise unnecessary delays caused by this human factor, which can probably best be done by shifting the cost and time burden as much as possible onto the master / owners and put pressure on them to be fully prepared with their load calculations & planning before and during the loading operation.
As mentioned this could be achieved by fixing cargo qtty in the CP, fixing the masters declared quantity on arrival of the vsl, putting trimming time on vessels account or some combination of these. As it is a human issue, some friendly negotiation with the master on load sequencing and minimising the final number of hatches to be trimmed also usually goes a long way to assist.
It should be noted that availability and quality of ships oficers is very much on the decline these days and this problem should not be underestimated, hence the need to have a very good and clear set of SOP's / instructions to masters for calling & loading at your terminal.
Best Regards
Kassim ■
Re: Avoiding Trim On Vloc
Hello Julian.
Thanks for additional information. Now I understand your situation and think I know how to resolve this problem with minimal losses or even without them.
First I€™ll recap what we have. You have draft restriction in approaching channel (avg 18-19m), vessels you have described 250K - 300K DWT, if I€™m not wrong, have next dimensions: LOA €“ 280-350m, Breadth €“ 40-45m, Draught €“ 19-25m, with 8-12 holds. I think the optimal for you will be 150K €“ 200K DWT vessels unless you dredge the channel. So, to load as much as it possible, you really need to complete the loading on even keel. If you€™ll have so long pier, let€™s set that you will operate by only one shiploader on one vessel. As you self declared, you can not avoid hatch changes due to the ship safety reasons, but you can optimize the sequence of loading. So, I wouldn€™t avoid the trimming at all, but include it in two steps before last one.
For example you have 15 steps in your loading sequence.
On 13-th step you must load cargo into hold which is on aft from hold with LCF, and you have to stop the loading just you reach maximum draught. But not exactly, so you can load on full capacity and stop the loading before some centimeters not losing the time.
On 14-th step you must load some one of forward hold where aft draught will reduce (see the €œCargo Trimming Table€ post on this forum). Stop the loading on even keel position. The chief officer or your load master will have enough time to re-calculate required quantity for given step when shiploader will travel from hold to hold. Here you allow to make mistake in few centimeters, it will not so difficult even on high rate if you€™ll have weight meter near to stock pile.
On the last step you have to set your shiploader exactly on LCF position of the ship and load there last quantity. Of course you should recalculate it when shiploader will change position. You€™ll able to correct the trim just turning the boom of shiploader inside the hold, don€™t stop the loading.
As you can see, in such manner we don€™t need additional shifts from fore to aft holds and vise versa while trimming. And you don€™t need to stop or significantly reduce the rate of loading. Of course at high rates of loading this is a difficult procedure, I would compare it with landing of airplane, but with each nest vessel you will do it better and better. I did it many times but with not longer than 260m LOA ships, but I€™m sure that it will work for >300m too.
And I entirely agree with Kassim. Don€™t forget about CP. Sometimes paper can do much more than super-modern siploader. And nowadays, due to lack of marine officers in the world, they are often will need your assistance or cooperation to prepare the best and same time safety loading plan.
And last one. If you€˜ll moor the vessels against to the cargo delivering direction, with sequence described above you can stop the loading on pre-last step with full conveyor what enable you to easily catch even keel don€™t reducing capacity of your shiploader.
Hope I€™ve poured some light on your question.
Best regards,
Vladimir. ■
Re: Avoiding Trim On Vloc
Dear Julian,
I see that you already have a lot of good feedback for your query, and it is evident from it that the question of time spent on trimming is common to most - if not all - bulk terminals. Frankly I do not see any way to eliminate it, and it is something we have to live with, even though there are ways to reduce the impact on terminal efficiency.
It is important to bear in mind that trimming is not only required to ensure that the maximum amount possible of cargo is loaded, but that it also has significant bearing on the seaworthiness of the ship when she sails and on draught considerations in the navigable channel. It cannot therefore be simply dispensed with by accepting a monetary penalty (eg. the deadfreight claims which you mentioned.)
As Kassim has emphasized, much can be done by implementing adequate operating procedures which are (and this is very important) previously agreed to and accepted by the ship during the pre-loading conference. Typically the trimming procedures should address such issues as: time permitted for the draught check; number of holds which can be used during the trimming rotation; minimum quantities for each pour; penalties for requiring additional pours; communications channels with shoreside during trimming, and others.
Regarding the Master's prerogative to request more cargo than he had declared before arrival you must be careful, because usually the Charter Party allows for a 10% more or less cargo call, at the Master's option, and if he is refused more cargo to complete that amount, including the tolerance, a deadfreight claim will certainly ensue. It is not practical for a ship to declare an exact amount to load before arrival, for the valid reasons given by Kassim, amongst others, and these are not just excuses for avoiding responsibility!
In short, and until some revolutionary changes are made in bulk-carrier and/or ship-loading equipment, trimming will remain with us, and it is necessary for bulk-terminal projects to design this restriction into their equipment requirements, and for the terminal operators to design it into their procedures, always bearing in mind the associated safety issues, and internationally accepted norms and practices (See the IMO BC Code, for example).
Kassim's comment on the quality and availability of ship's officers is valid, and it is important for the Loading Master to be continually on top of events during the draught check and trimming.
Good luck in your important and interesting project!
Steve Catton ■
Untitled
Hi Kassim and Vladimir
I understand what you are saying the point is we have many years to work on the contract side of how we manage this but I need to define the process we will use now. The wharf will take 4 to 4 years to build.
Most VLOC will load in 18 or 20 pours. I will need to speak with ship captains to see what the issues would be looking at our operation and also discuss the process with marketing.
Normally we have around 3000t for trim on most ships. I would be more interested in loading the maximum as Vladimir has stated in his process and then use ballast water as a last resort only if the next ship required a different product. You have given a lot more data to add to my options. I just need to fin the middl ground here so we can design a process around these suggestions.
The CP should also address this as much as possible as per the process discussed above.
One last question: If you had a vessel of 230000DWT and you wanted to load at 8000tph and then ballast down the vessel with water if required for final trim. What percentage of cargo would you short load to accommodate this safely for all ships (i.e. 5% of total cargo?) if you maintained less than 1% weight error at all times.
Thanks all for your help and advice, I have learnt a lot and would still like to hear from anyone else who has lost sleep over how you can do this like I have. ■
Re: Avoiding Trim On Vloc
Hi.
I would really like to help you, but I can not exactly understand your question. If you€™re asking how much less cargo you can load onto 230000 DWT ship, the answer is as less as you like. Even if you load only 100K instead 230K vessel will ready to sail safely. The question is not how much you will load but how you will distribute this cargo between the holds. The main safety parameters for ore caring by ship are: ship has not to be trimmed to forward (but it can be trimmed to aft if no other restriction); ship maximum draught must not exceed any voyage draught restrictions and summer draught of the ship in sea water; metacentric height (GM) must be positive and better if it will not exceed 5m; the pressure on hold€™s bottom, bending moments and shearing forces, and hogging or sagging of ship created by cargo distribution must not exceed permitted values; ship€™s draft must be enough for proper steering the ship. If all this conditions satisfied, ship laden by ore is ready to sail. The problem may occur when you stop the loading near to the maximum permitted draught (whether summer draught or port restriction) and some of draft marks will deeper than permitted or ship will have trim to forward. In this two cases ship must take ballast in order to correct the trim, and here you should be very careful because remained draught may be not enough to correct the trim by ballast. For example if you stop the loading with 1m trim, such big ship will need to take abt 2500 tones of ballast (this figure may differs on each vessel in wide range), so theoretically you should stop the loading in 2500t. before maximum quantity. If you stop the loading with trim greater than 2m, very probably ship will not able to correct the trim only by ballast due to luck of necessary compartments or draught. And don€™t forget about hull deflection, it is very important issue if ship is longer than 180m, often trim problem will be on the back.
So I think your question is when you should stop the loading to make safe trimming by ballast but same time load as much as it possible but safely, and you want to load all time on full capacity, then stop and start to load new vessel. If yes, I have next opinions. If you will complete the loading by hold which is near to aft or forward of ship you will need to short abt 5000 - 7000 tones of cargo (because of trim, hull deflection and weight meter€™s error too) and I wouldn€™t recommend to exceed 1.5m trim though. If you will complete the loading by hold which is near to midship with more or les small trim, this quantity can be reduced to 1000-1500 mt.
Good luck and bye.
Best regards,
Vladimir. ■
Untitled
Hi Vladimir,
Thanks once again for your valuable input.
One solution given the potential length of the belt with 13000t of cargo on it is to do running draft checks when you get to within 20000t left to load (say 2-2.5 hours out to confirm error and adjust the load accordingly). The surveyor would be asked to confirm the final tonnage required prior to the final 13000t of product being reclaimed and loaded onto the belt. Once the reclaimer has finished reclaiming this amount for the final hold before trimming (say 7000t) the product will be broken up into 500t lots with 1 min between them on the belt for a total of 4000t that can then be used for final trim. This is all the ship would be allowed to take once the surveyor had done his calculations to load the ship to the best of his ability.
We could basically guarantee the static tide only here, but we would have more draft available if DUKC was used as a buffer process (normally 30cm) to allow more draft should something go wrong so a VLOC can take on more cargo unless loaded to their summer daft marks..
Any thoughts about this as a process? ■
Re: Avoiding Trim On Vloc
Hello Julian,
It's a great idea to complete loading by portions. But i would increase the rest period from 1 up to 3 or even 5 minutes, depend on weather condition and draft reading technique. In case of 1 minute I think surveyors will have to stop you anyhow, of course unless you'll use 6 good experienced persons to read each draft mark in real time. And here you'll face again with your doubts about remaining of cargo on conveyor. If next ship will need another grade of ore, you should have contract capable to cover such percentage of mixing or you should do this only if next vessel is waiting for same grade. But anyhow it's a very good idea in your situation.
About DUKC. It is a next step after standard calculation technologies of under keel clearance that we have used today. Of course with this you will have opportunity to load more cargo because when we calculate clearance for given tide, we usually takes maximal safety values. DUKC allow us to take in account present weather condition including weather forecast and inertial moments of the certain ship in certain loading condition. DUKC is a partly prediction system and it accuracy will depend on how stable or predictable tides and weather changes in your area. Next question is how you going to use it: every time to always load more cargo, or only when something wrong and you want to sail ship safely?
Vladimir. ■
Re: Avoiding Trim On Vloc
Hello Juliancw:
Most ships today have a loading calculator onboard, and as long as the ships officers know how much fuel, FW, Stores, Constant of the specific ship and specific density of the water at the location, it should be possible to calculate approx accurate how much cargo it can load.
Also trim will be possible to calculate approx, but not exact, so terefore it will be neccesary to or common to have one or to stops to get trim exact.
My focus the last 10 years have been to develop new ship types for transport of free flowing bulk material, in a way that shore terminals can build and modernize with large savings in infrastructure, and simpler conveyor systems than now, this will give considerable savings.
Also with reguards to environmental aspects like spill, dust, noise.
This ship type can load itself from one location and distrubute cargo inside the ship itself, no need for travveling conveyor systems.
When the ship is finish with loading and if it should be the need to trim the ship to "even keel" it can do this it self, it can transfer cargo from on hold to another.
This shiptype can be made in many variasion, and it will be possible to make specific custom design, also for special needs, from to serve a specific route to be able to sail world wide and load with cranes or conveyor belts, and should be possible to adopt to different solutions, in loading and discharging operations.
If a ship like this shall take cargoes from one port to two or more ports it will be possible to retrim itself to actual draft at this locations.
This shiptype can have a large loading and discharging rate, and can in the future be a mobile link between loading and discharging ports, so the ports can manage with simple and maintenance friendly shore equipment, environmental friendly with minimum spill, noise and dust.
Today when we see the ship building boom, and that ship owners and ship yards build a huge amount of simple, low standard bulk carriers to a very high price, and a second hand ship is about double price of a new building, to be able to have as much profit as possible as quick as possible, and we see all time high bulk rates time after time, it could be an oportunity to think in new directions, when this shipbuilding boom cease, then the capacity of the worlds shipyards will be extreamly high, and the prices for building ships will go drastically down, then new ship types like this might be able to build at a price competitive to simple low standard bulk carriers, and the new types will be a lot more efficient and cost efficient.
If this issue can be interesting, I look forward to hear comments.
Best Regards
Malvin Matre
Mail: malvinm@online.no
004792437215 ■
Re: Avoiding Trim On Vloc
Dear Julian,
Before signing off, just thought to mention one should always be prepared for the unexpected. Ballasting tanks is very much the prerogative of the master within the capabilities of his vessel, whereas under contract, trimming may be your responsibility.
In the current shipping scenario, where handy size bulkers of upto 30 years of age are still carrying Iron ore to China, often their pumps are not working properly or masters are hesitant to ballast tanks due to questionable condition of pipes / tank tops.
Hopefully you would not encounter such situation on your VLOC's which are probably very modern and well maintained. But you never know. If you are a cricketer you might think of it as being prepared for the googly.
Best of luck.
Kassim ■
Re: Avoiding Trim On Vloc
Dear Juliancw:
Kassim Gokal have right when he say that deballasting ships might cause many problems during such operations.
If it is the ballast pumps which cause this; then it is related to the skill of the engine department crew related to daily routines, maintenance, understanding of and use of this system, or the companies "will" to support the ship with spare part, new pumps.
When a ship become over 10 years old one can start to expect problem with ballast pipes, (before pipes last some longer due to thicker steel pipes) this can be caused by rust, or crack when large grabs hit the tank top, stress, etc, then it will be problem to pump out ballast because the pumps suck false air etc...
In all years ballast have and probably will cause problems, and i dont think it will be less problem with the ships the yard produce today in a large scale, simple design, spec, and that it is not enough skilled crew on the world market to man the ships. ■
Untitled
Hi all,
I have read with great interest all of the issues and feel we have a process we can now work on. Thanks for all of your feedback and valable input.
I can say that we do not accept ships over 25 years of age at any terminal.
Below is my general process I am working on, I have included this as others may like to comment or look at a similar system.
I have also looked at the contract side of this process to see if we can reword the documents.
Basic Summary and findings.
So: Can outloading rates be maintained while changing a process that would allow ships to trim as required without a loss of vessel safety, this process must allow ore to remain on the belt thus removing the need for more infrastructure?
Answer:
The potential delay from this extended supply line is unacceptable. By using accurate weightometres and the development of a sensible process linked with smart technology the delay invoked by the length of belt can be minimised.
This process will require a more hands on approach by the surveyor. By changing the present process we can still achieve the same result without stopping the reclaimer for more than a few minutes dependent on the distance to the next hatch. This new process will depend on the skills of both ship and shore persons responsible for loading.
When 80% of cargo is loaded, the Chief Officer and Loading Coordinator will start to recalculate the quantity remaining to load according to actual draught and load plan, allowing them time to recalculate the new required total cargo without the need to run off each pour by breaking the reclaimer flow into predefined gaps. They will have to do this more often when close to final trim.
They must both know the accurate quantity hold by hold, and the shiploader must advise the ship’s officer about the tonnes loaded after every hatch change so the weightometre error can be calculated before the last 13000t is required.
Our terminal surveyor must participate in all calculations so he has full control over this entire loading process as communication is paramount.
Ships should also be encouraged to have a computer assisted program for ship trimming (not all do). Also, the loading surveyor should have access to such a program as it will significantly reduce downtime while final trimming operations take place.
Ships could also be supplied with a WAP enabled screen that shows them accurate loading rates, amount loaded into each hold and the loading plan as set out in Citect as this will assist them in understanding our operation and what we are doing at all times.
The process below is an example of how this would work.
Please feel free to add anything you feel should be addressed.
Attachments
■
Avoiding Trim on VLOC
Hello,
I am working on a project to see if you can avoid trim and I would like input from others in the industry if this is possible.
I have been given a task to look at reducing trimming on a VLOC (230000DWT) on a new wharf we may build in the future.
The new berth could be very long and fitted with traveling shiploaders so you can load one side and then the other side and we need to reduce costs due to the expense of the real estate this far out. One of the issues we would face is the time required for vessel trim. If a ship needed 3000t for cargo trim it may take 45min to 1 hour to reclaim and deliver the ore and it would be cheaper for us to ask the ship to take on ballast water and incur a dead freight claim than loose this much production downtime for each ship.
Trim bins are one solution, but due to the size and cost to build this far out andlack of availabe realestate, we would prefer to look at other solutions if available in the world.
Some that we have thought of are as follows;
Load the same product at all times off the two adjacent berths (one product per ship, not two or three), this would allow this one product (iron ore grade) to be left on the belt for the following ship and not be an issue.
Ballast the ship ddown using salt water for trim and pay the dead freight costs avoiding trim altogether. I am not sure on how much the ship would need to ligh load to allow this.
See if there is any electronic process in the world that allows you to check the trim while loading so you get very accurate pours. I do not think there is any system like this but would be interested to know if there is?
Load the incorrect product on occasions if required into the product already loaded. If a ship had 20000t in a hold and we placed 1500t of the wrong product due for the next ship into the hold would this be an issue with product grade.
I was wondering if any dry bulk terminal has faced similar issues. If so, I would greatly appreciate their knowledge and advice. I would also be interested in any knowledge they have.
If you have any other solutions for this trim issue, your ideas and suggestions will be valuable in finding a solution. It may be one we have totally overlooked or not even considered. I would also be happy to hear what issues you could see ships having if final trimming pours were not an option. ■