carrying an endorsement that the ship’s equipment was in good working condition. In many places, shore cargo inspectors are reluctant to describe oil as ‘unpumpable’ and may prefer to use the terms ‘liquid/non-liquid’. This is not satisfactory and should be avoided if at all possible because it leaves cargo owners in a position to claim pumpability and to attempt to activate a charterparty retention clause, albeit unlawfully, if the clause requires the cargo to be pumpable.
It is strongly recommended that masters contact their UK Club representative and the ship’s operators for advice if a dry tank certificate showing oil remaining onboard as being unpumpable cannot be obtained.
Ballasting
Where permanent ballast tanks are fitted, it is normal practice for these to be filled during the discharge in order to expedite the ship’s departure. It is, however, recommended that other ballast tanks not be worked simultaneously with cargo operations as this will certainly entail the risk of contaminating the cargo. Should ballast, in addition to the permanent arrangements, be required then such ballasting is best completed after the discharge and after the inspection of the cargo tanks.
In-transit losses and their potential causes
In the past the standard defence put forward by a shipowner to a cargo shortage claim was that the loss was below or equal to 0.5% of the total cargo. This figure, which originally stemmed from the cargo insurance deductible, has been used by shipowners and cargo insurers as a yardstick for transit losses for many years. However, a number of courts, particularly in the United States, have rejected the concept of an automatic ‘loss allowance’.
Nonetheless, there is every indication that the same Courts would allow a ±0.5% ‘measurement tolerance’. In transit losses and their causes can be considered under four headings:
● The true in-transit losses during the voyage where the ship’s gross volume at standard temperature on loading is compared with the vessel’s gross volume at standard temperature prior to discharge
● Theoretical in-transit losses when the comparison of net volume onboard at standard temperature on completion of loading is compared with the net volume onboard prior to the commencement of discharge
● Emptying and filling losses. This is particularly pertinent where a part discharge may take place into a lightering vessel or barge
● Additional losses which may occur as a result of crude oil washing.
The third and the fourth items become apparent when accounting for volumetric losses on outturn.
Various factors including permutations of tanker design, cargo density, Reid vapour pressure, cargo temperature, ambient temperature and general weather conditions, may combine to cause a release of gasses and an increase in pressure within the cargo tanks which, combined with the inert gas pressure, may cause venting through the pressure vent valves and consequent loss of product.
Losses during discharge
The largest volumetric losses are likely to occur when there is transfer from one container to another. This means that quite large losses can occur when pumping the cargo from the ship to the shore. Where lightering is
10
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32