CARRIAGE OF RICE
Published: December 1, 2015
The carriage of bagged rice cargo is a potentially hazardous undertaking, with claims running to millions of dollars when problems arise – particularly in the trade between South East Asia and West Africa. The loss prevention department has worked with CWA Food and Dry Commodities Group to identify the problems encountered in this trade and to share with Members best practices that can eradicate or substantially reduce a Member’s exposure to costly disputes and claims.
The major issue with cargoes of bagged rice is the formation of mould or caking which can often be attributed to condensation due to inadequate ventilation or water ingress. Other issues include shortages due to pilferage and damage to bags which are torn, slack or lost overboard during stevedore operations. Finally, infestation and fumigation problems are also common in this trade.
ORIGIN OF RICE CARGO
It is estimated that over 41 million tonnes of rice will be exported globally in 2015. The major exporting countries are Thailand, Vietnam, India, Pakistan and the US. Rice from South East Asian ports has traditionally been shipped in polypropylene bags, although some is now being shipped in containers. Rice is shipped in bags or in bulk from US ports and in bulk from the developing rice trade in South American countries. Club correspondents in Thailand have recently advised that, due to a stevedore shortage, a large proportion of rice exported from Thailand is currently being shipped in bulk.
After harvesting, rice needs to be dried to ensure safe storage and carriage. If rice is not adequately dried or properly stored, it may become infested with insects or subject to mould growth and can also be contaminated by noxious odours.
Rice kernels should ideally have a moisture content of between 13% and 14%. Indeed, a moisture content of 14.5% should be regarded as the upper limit and in case of any doubt, samples should be sent for testing and a note of protest issued if the moisture content is any higher. A moisture content in excess of 15% when combined with a relative humidity of over 75% can also result in the cargo self-heating. In addition to moisture content, temperature is a key factor when carrying rice cargo. While the ideal carriage temperature for rice is in the range of 5°C to 25°C, mould can develop at higher temperatures. When temperatures reach 25°C and above, the increased metabolic processes can also lead to rice kernels caking or sticking together.
Proper cargo care and careful monitoring by ship staff and surveyors during loading, carriage and discharge are essential in order to prevent damage to the cargo and avoid possible claims. Precautionary surveys at the load port are very useful in ensuring that the cargo is loaded and stowed in accordance with industry guidelines. They also provide good evidence of the quality of the cargo at loading. Similarly, tally and discharge surveys are essential to minimise cargo loss and damage, particularly due to mishandling or pilfering. The likelihood of pilferage of rice cargo in particular means the tally should be conducted as close to the ship’s rail as possible.
Ship staff should monitor the local and forecasted weather conditions prior to and during loading and discharging in order that cargo operations can be stopped and the hatch covers closed in good time to minimise cargo damage due to precipitation.
Good practice guidelines during the various stages of carriage are as follows:
Food grade cargoes are susceptible to contamination by previous cargo residues, paint, rust chips and odours. Therefore, cargo holds should be properly cleaned and prepared, ideally to grain standards. The accepted definition of ‘grain clean’ is provided by the National Cargo Bureau which states that: ‘Compartments are to be completely clean, dry, odour-free and gas-free. All loose scale is to be removed.’
Shipowners are responsible for maintaining hatch covers in a weathertight and good operational condition. Hatch coamings, hatch packing, ventilators, hydraulics, drain channels, etc. should be checked, ideally using ultrasonic tests to verify weather-tight integrity.
For bagged cargoes, the type and application of dunnage should be agreed in advance. Properly constructed and applied dunnage is essential to prevent wet damage due to condensation or water ingress, and the dunnage should cover the steelwork as much as possible.
The type of dunnage in general use is a layer of plastic sheeting and kraft paper placed directly against the side shell plating and tank top, with two layers of kraft paper on top of the stow. Bamboo, wooden or styrofoam struts placed along the sides of the hold and on the tank top are used to create a space between the steelwork and the bags.
Some charterers prefer to place the kraft paper directly on the tank top or side and then to cover with the plastic sheets, on the basis that this arrangement bundles the cargo as in a ‘plastic bag’. However this method can leave the cargo particularly susceptible to damage by condensation and so ship staff should be aware of this possibility of condensation damage. The ship staff should keep a photographic record of the applied dunnage prior to and after completion of loading.
The stowage plan should incorporate any specific stowage instructions, cargo separation, ventilation and dunnage requirements, particularly for bagged cargoes. Variations in ambient air and sea water temperatures en route can lead to the formation of condensation and, for bagged cargoes, adequate ventilation channels should be provided within the stow during loading. The location and number of these channels will be determined by the carriage instructions.
Ship staff should monitor the temperature of the cargo throughout the loading process and should also monitor the cargo being loaded for signs of damage, mould, insects, wetness or staining etc. Any cargo or bags not in sound condition should be rejected. A Letter of Protest should be issued and ship staff should always take photographs to help defend any potential claims.
INFESTATION AND FUMIGATION
The discovery of insects, pests or their residue in the cargo will generally lead to fumigation. Good sealing of all hatch covers, vents and accesses is necessary for fumigation to be effective. In accordance with the Merchant Shipping (Carriage of Cargoes) Regulations 1997, where pesticides
are used in the cargo spaces of ships prior to, during or following a voyage, the IMO’s MSC.1/Circ.1358 (30 June 2010) – ‘Recommendations on the safe use of pesticides in ships’ must be complied with, as appropriate. Written instructions should be provided to the master by the designated ‘fumigator-in-charge’. The instructions should be in a language readily understood by the master or his representative and must contain details about the type of fumigant used, the possible hazards to human health and the precautions to be taken.
The most widely used fumigant is phosphine (hydrogen phosphide PH3) but it must be noted that this gas is highly flammable and the fumigation process requires a longer period of time, at least three days, to work completely. Methyl bromide is used in situations where a rapid treatment of spaces or commodities is required and fumigation can normally be completed in less than 48 hours.
There are a number of different methods for application, particularly of phosphine. These include:
- surface application – fumigant applied to top surface of the bulk cargo
- trench application – a trench is dug and the fumigant placed at the bottom of the trench
- probe system – a probe is inserted into the cargo and fumigant introduced via the probe
- tubing along the side and bottom of cargo holds – using a combination of tubing and an explosion proof blower, via which the fumigant is circulated throughout the cargo.
Unfortunately, fumigation of bulk grains is often ineffective because it is difficult to attain a suitably deep penetration of the fumigant gas into the stow.
Following the fumigation process, ventilation of any treated spaces should be completed in accordance with the guidelines provided and a gas-free certificate issued before any personnel are permitted to enter.
3. DURING THE VOYAGE
Most agricultural products contain natural moisture and the degree to which they may absorb, retain or release that moisture will depend on the surrounding atmosphere.
Ventilation requirements The purpose of ventilation is to replace some of the relatively warmer moisture-laden air inside the holds with drier outside air, thereby reducing the potential for condensation. Wherever possible ventilation should be conducted in accordance with the carriage instructions provided and, obviously, when the weather/sea conditions permit.
As a general rule, cargoes loaded in a cold climate and transported to a warmer climate are not ventilated, whereas cargoes loaded in a warm climate and transported to a colder climate are ventilated. If rice is being carried as a bulk cargo, surface ventilation will be required, and for bagged/general cargo, surface ventilation as well as ventilation via channels in the cargo will be required.
‘Ship’s sweat’ may form on the ship’s steelwork (including the sides of the hold, hopper tanks and tank top) when the dewpoint of the air in the cargo hold is higher than the temperature of the steel. ‘Cargo sweat’ may form when the dew point of the air in the hold is higher than the temperature of the cargo i.e. if loading in cold climates and proceeding to warmer climates.
When deciding whether or not to ventilate the cargo, ship staff should use either:
- Dew Point Rule – VENTILATE if the dewpoint of the air inside the hold is higher than the dewpoint of the air outside the hold.
DO NOT VENTILATE if the dewpoint of the air inside the hold is lower than the dewpoint of the air outside the hold.
- Three Degree Rule – VENTILATE if the dry bulb temperature of the outside air is at least 3°C cooler than the average cargo temperature at the time of loading.
DO NOT VENTILATE if the dry bulb temperature of the outside air is less than 3°C cooler than the average cargo temperature at the time of loading, or warmer.
If bad weather prevents ventilation, the ship staff should record this, take photographs of the prevailing weather conditions, especially if sea water or spray is being shipped on deck, and issue a Sea Protest.
Upon arrival at the discharge port, particularly if the port is in West Africa, it is common to face delays. When a delay occurs, it is vital that the ship staff continue to take temperature readings, ventilate the cargo as required and record all these actions in the deck and ventilation log books. To aid ventilation, if the weather conditions permit, the hatch covers can be opened, subject always to stability considerations. The cargo may also require refumigation and this will require the consideration of competent and reputable fumigators.
It is also advisable for ship staff to keep a close watch on the stevedores during all cargo operations and to take photographs of and report any stevedores that are:
- using hooks which may damage the bags
- mishandling the bagged cargo
- overloading slings
- apparently pilfering the cargo.
In the event of any of the above, the master should issue a Letter of Protest.
By following the key measures outlined in this article relating to the safe carriage and care of the rice cargo, it should be possible for shipowners to minimise and eradicate most claims. The loss prevention department is always available to support Members and respond to their questions. The master and the ship staff should remain watchful and alert throughout the venture. If a Member experiences any problems pre-loading, during the voyage or at a discharge port then they should contact the Club and the local Club correspondent.