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Cargo discharge plan ,draft survey & cargo calculation for bulk carriers
The object of bulk carriers cargo discharge plan is to discharge cargo safely to reduce likelihood of ships structure overstressed during cargo work and to remain within the limitations as specified by the classification society . And the ultimate goal is to deliver cargo in the same condition it was loaded.
The discharge plan is to show the distribution of cargo within the ship and is sent to the stevedores before arrival in port so that they can arrange the required labour and equipment .
The main consideration when discharging is to avoid stresses due to inappropriate distribution of weights. This is easier in the discharging phase as the cargo operations can be monitored more closely. However, the degree of vigilance required by the watchkeeping officers remains the same. When hatches are being opened the OOW should always be present. At the discharge port, attention should be paid to the UKC as many ships will wait for high tide before berthing alongside.
Prior to arrival, the chief officer should devise a sequence for discharging cargo, calculating BM and SF as well as draughts and air draughts for each run. This eliminates any communication gaps between the stevedores and the ship's officers and allows the stevedores, in particular, to plan ahead. However, this can only be done if the ship is provided with the cargo discharging rate and number of gangs available at the discharging berth.
It is important to emphasise again that every stage of loading ballast should be considered, keeping the longitudinal stresses in mind.
Fig: Bulk cargo discharging- final stage
When the discharge plan has been prepared, a signature should be obtained from the stevedores to confirm their agreement. The watchkeeping officers should then be fully briefed about the operation to ensure their understanding and compliance at all times.
The plan should be amended only by the chief officer, who should also inform the relevant personnel. The watchkeeping officers should be extra vigilant in the completion of discharging from any cargo hold, particularly if grabs, bulldozers or other similar equipment is being used within the hold. This is to ensure that the stevedores do not cause any damage and, if any damage is caused, that the chief officer/ Master is immediately notified and an entry made in the logbook.
Once the discharging is complete, the watchkeeping officer should inspect the cargo hold to ensure completion of discharging and that the ship's structure has not been damaged in any way. Many ports require Masters to issue an empty hold certificate on completion of discharge, while the P&I Clubs recommend obtaining the same from receivers or stevedores. Normally, one party prepares the certificate and the other signs to acknowledge it.
Arrival at the Discharge Port
Upon arrival port some preparations that need to consider:
- Once the appropriate paperwork has been completed, usually the first task is to conduct the draught survey. If the consignee has not appointed a draught surveyor, the chief officer should still carry out the calculations for the ship's records
- to safeguard the shipowner's interests, it is important to inspect the cargo's condition as soon as the hatches are opened. Where cargo damage is suspected, taking pictures before commencing cargo operations is highly recommended. Any damage to the ship's structure or the cargo should immediately be noted
- if the receiver has appointed a draught surveyor and the charterparty does not specify anything about opening of hatch covers prior to berthing, then these should be opened in his presence to obtain evidence if needed.
Notice of Readiness
The requirements for tendering the NOR apply to the discharging port in the same manner as for the loading port. The laytime commences only if the NOR has been accepted.
Cargo Samples when Discharging
Similar to the cargo sampling requirement at the loading port, the receiver may ask the ship to provide samples of the cargoes prior to discharging operations.
Cargo Calculation - Draught Survey
Cargo quantity discrepancies are quite common in the bulk cargo trade, even though there may be no obvious reason for a discrepancy. There are a number of possibilities for the final quantity of cargo:
i)An ideal situation is where the quantity of cargo loaded is exactly the same as the quantity of cargo discharged, there are no discrepancies and no likelihood of disputes
ii) another situation is where the cargo quantity established in the discharging port draught survey is more than that for the loading port. In this case, either the cargo may have absorbed moisture or more cargo was loaded than intended
iii) the third situation is where there is a short landing of cargo. In this case, the receiver usually files a claim against the carrier. The Master should immediately inform the charterer, managers and P&I Club as appropriate to seek advice.
In the majority of cases, if the cargo has been loaded in one port and discharged in another port, the cargo quantity discrepancy is merely a paper exercise without any factual exchange of finances. However, if the cargo has been discharged in more than one port, to resolve the issues, surveyors are called in by all concerned parties to estimate the quantities based on figures obtained by draught surveys, etc.
During a voyage, a surprising amount of water can be discharged from the bilge depending on what cargo is carried, the location and the weather at the time of loading. Cargo stored in the open ashore can accumulate and retain water for many weeks prior to loading. Over a prolonged voyage a considerable weight, ie in excess of 100 tonnes on a 4 week voyage, can be discharged. This illustrates this necessity of keeping a bilge water drainage log.
- Cargo damage survey guideline
- Cargo handling guideline for bulk carrier
Classification of various dry bulk commodities
Our detail pages illustrated many safety aspects of Bulk carrier
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Operation of sea going bulk carriers involved numerous hazards . Careful planning and exercising due caution for all critical shipboard matters are important . This site is a quick reference to international shipping community with guidance and information on the loading and discharging of modern bulk carriers so as to remain within the limitations as specified by the classification society.
It is vital to reduce the likelihood of over-stressing the ship's structure and also complying with all essential safety measures for a safe passage at sea. Our detail pages contain various bulk carrier related topics that might be useful for people working on board and those who working ashore in the terminal. For any remarks please Contact us
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