Ship to ship transfer is a common practice in the oil and gas industry, and its importance cannot be over-emphasized. It is an essential process that involves transhipment of cargo from one vessel to another. Why is ship to ship transfer essential when conveying cargo to end-users or consumers? Let us get started!
What is Ship-to-Ship Transfer
Ship to ship transfer is a process where a tanker’s cargo is partially or fully discharged into another for onward freight to a port of discharge. Typically, STS is a common practice among shippers of petroleum products, natural gas, and other consumable liquid or chemicals.
Also, it could be employed when freighting crude oil from production points (onshore terminals) to refineries. In addition to that, traders also use it when conveying petroleum products from refiners to bulk buyers and marketers.
Furthermore, a transhipment may take place while both ships are underway or stationed through mooring.
Why Ship to Ship Transfer?
There are three reasons oil merchants opt for STS transfer operations – partial discharge, shallow terminal depth, and cost-effectiveness. Without wasting too much of your time, let me give brief explanations on each of them.
Traders opt for sts operation to carry out a partial discharge. Merchants adopt partial discharge when a mother vessel needs to distribute cargoes to different ports and possibly, countries.
STS is the only available option in shallow terminal depth. There are limits to which Very Large Crude Oil Carriers (VLCC) can reach for loading or discharging. Therefore, some merchants have to settle for a ship to ship transfer. In other words, the terminal depth determines the size of the vessel that could berth to load or offload cargo.
Ship-to-ship transfer is cost-effective. STS operations are cost-efficient. The reason being that tankers do not have to berth and pay port berthing charges. Furthermore, you are not only saving money but also saving berthing and mooring time.
Requirements for Conducting STS Operations
Here are a few requirements for STS operations which include training of crew members, use of high-quality STS transfer equipment, and adequate provision for fire fighting. Further conditions include the provision of an excellent communication channel, obtaining permits from the port authority. Finally, giving enough consideration for weather and nature of the cargo.
Permit me to explain further.
Take time to train your crew members. Make sure you give your crew members enough training. The reason being that they cannot offer what they don’t have. Give them the much-needed intensive training, and they will be so good at their jobs.
Make use of high-quality STS transfer equipment. Employing good hands is not enough as you also need high-quality STS transfer equipment. Also, they must be the right and well-kept equipment.
You must make provision for firefighting. Make sure you lose neither your cargo nor your crew members to a preventable fire incident. Safety of lives and product is attainable if you make firefighting personnel and equipment readily available.
Be sure to consider the nature of cargo in your decision making. Another thing that you should be mindful of is cargo type and its volume. Typically, likely hazards from corrosive products differ from that of refined petroleum products. In order words, different products require different measures. Note that this doesn’t mean they all don’t share so many processes in common.
You must provide an excellent communication channel. One vital requirement for successful STS cargo transfer is the provision of a perfect interaction channel. Interaction between the two vessels and crew members must not break down.
Do not forget weather conditions in your decision making. Another thing that worth mention here is the weather condition. First, get to know the weather forecast for your preferred operation time. Second, get to know if there is going to be rainstorm or the sea likely going to be stormy?
Other Requirements
You must obtain all required papers from relevant bodies. Do you have the needed permission from the state’s port authority? Ultimately, you have to get all necessary permission before embarking on any cargo transfer operation.
Your vessel captain must respect navigational warnings. Mandate your vessel captains to pay enough attention to the navigational alerts and display broadcast. Any carefree attitude or disregard for display broadcast will put the vessel and the entire crew in danger.
I am sure you don’t want any saboteur to mix up with your cargo officers. There is a need for proper badging of both tankers’ cargo officers.
What Are The Risks Involved in STS Transfer?
Some of the risks involved in STS transfer include stormy sea and bad weather condition as well as failed equipment. Further threats include cargo overflow, faulty cargo pump, tank explosion and collision.
Moreover, every trade or operation has its peculiar downsides hence ship to ship cargo transfer isn’t risk-free. Let’s take a look at each of the risks.
First, poor weather condition could work against STS transfer. Moreover, placing two vessels alongside each other when the sea is stormy is not a good idea. Ultimately, it will spell doom for an STS transfer operation.
Second, failure of machinery and tools is another risk that may likely hamper a ship to ship cargo transfer operation. Equipment failure could be as a result of low equipment quality or decay.
Third, you should be wary of cargo overflow? It is one of the risks operators have to deal with in STS transfer operations. To avoid cargo overflow, crew members must pay attention to all tank level gauges and high-level alarms.
Fourth, there is a risk of tank explode if pressure valves fail. Also, an explosion may occur if the two ships are involved in a collision. Further, there is a high tendency that both mother vessel and daughter vessel could collide in the course of their manoeuvring.
Causes of Incidents during STS Transfer Operation
Some primary causes of incidents in ship-to-ship transfer include improper manoeuvering, inadequate communication system, mechanical fault, and poor mooring condition. There cannot be incidents without underlying causes. Let me explain each of them.
First, an improper manoeuvring tanker will cause havoc. However, a skilled vessel captain will reduce the shipping speed when manoeuvering to prevent needless incidents.
Second, inadequate communication or its outright breakdown will surely spell doom for any ship to ship transfer operation.
Third, another likely incident you cannot rule out when carrying out a ship to ship transfer operation is a mechanical fault. One of the two vessels could experience engine failure, thereby ruining the whole exercise.
Fourth, as I said in risks above, a poor state of mooring equipment will sure result in mooring failure and invariably result in incidents. Unlike oil shipment through pipelines, STS transfer operations require skilled crew who are good at the job.
Ways to Prevent Incidents during STS Transfer
You can avert incidents in sts transfer by having STS operation plan, choosing the right location for the exercise, and putting weather conditions into consideration. Other preventions include considering the traffic density in the proposed mooring point, hiring of skilled crew members, and strict adherence to safety measures.
Every problem has a remedy. However, proactiveness is an essential ingredient for business operations.
First, choosing the right location for STS transfer operation is essential for you to have hitch-free cargo transfer. Ultimately, a wrong mooring point will disrupt all your plans.
Also, do not forget traffic density in the proposed location for the STS transfer operation? You need to be wary of areas with high traffic to avoid hitches or accidents.
Furthermore, adhere to your STS operation plan. Also, make sure your operation plan conforms to an approved standard. Most importantly, make sure it comes in a language all crew members understand. Remember, total grasp is essential.
Also, do everything within your reach to adhere to safety rules at all times. Note that accidents are unpredictable but strict adherence to safety rules will in no doubt save you from avoidable incidents.
Above all, You need well-trained professionals to carry out safe STS cargo transfer. The man in charge must be versed in all areas of the entire operation to ensure proper coordination. Also, every member of the team must be vigilant at all times because a little lapse can cause fatality, losses and pollution.
Requirements before unmooring
There are basic guidelines for unmooring which include checking to know the quantity of loaded cargo, proper sealing of tank openings, and proper hose-draining before disconnection.
Additional measures include adequate communication between the two vessels and agreement on the detaching method. Also, make sure the two ships have properly-functioning engines and gears.
Now that you are through with your cargo transfer, what next? You need to unmoor the vessels for them to sail separate ways.
You must check loaded cargo quantity. Checking to know the volume of cargo is essential to prevent an overflow. Be sure you have not overloaded your vessel to avert loses or accidents.
Maintain proper draining and closure of tank openings. Now that you are satisfied with the loaded volume, it is time to close the tank openings and drain the hoses to avoid oil spillage. Furthermore, carefully detach the hose and park them as required.
It is time to agree on the method of detaching. The two tankers must agree on the ways to unmoor from each other. The basis for that is to avoid incident after a safe transfer. Ultimately, there must be proper interaction between vessels officers before unmooring starts.
Make sure each vessel sails away safely. The last but not the least in the STS operation is safe sailing. Make sure both vessels’ engines and gears are in good condition. Don’t forget to read up another related article on Oil Cargo Discharge Safety.
Let me round off by saying ship to ship cargo transfer operation requires functioning equipment and proper coordination. Therefore, cargo officers must exhibit care to avoid environmental pollution and incidents.
Also, in an STS transfer operation, a mother vessel delivers while the baby vessel receives the cargo. Also, the mother vessel usually acts as the terminal while the daughter vessel moors.