Challenges with Documentation in Tanker Voyage Claims

Accurate documentation is critical in tanker voyage claims, yet common pitfalls often weaken a vessel's defense in disputes. Letters of Protest (LOPs) serve as key evidence of delays or inefficiencies, but frequent issues—such as vague wording, delayed issuance, or lack of acknowledgment—can diminish their effectiveness. Ensuring LOPs are precise, timely, and addressed to the right party strengthens their impact in claims.

Similarly, pumping logs play a crucial role in verifying compliance with charter party (CP) discharge requirements, which typically mandate completion within 24 hours or maintaining a minimum manifold pressure of 100 PSI. Incomplete logs—missing pressure and rate changes, vague remarks, or absence of terminal representative signatures—often lead to disputes over vessel performance.

To objectively assess a vessel's pumping efficiency, the Pumping Performance Calculator provides a physics-based method for determining achievable flow rates at different back pressures. The formula, which considers that discharge pressure varies proportionally to the square of the flow rate, ensures accurate performance evaluations and strengthens a vessel’s defense against underperformance claims.

In the following sections, we delve deeper into the common challenges with LOPs, the pitfalls in pumping log documentation, and the application of the Pumping Performance Calculator. By implementing best practices in documentation and performance assessment, tanker operators can significantly reduce disputes and improve claim outcomes.

1. Letters of Protest (LOP)

LOPs are crucial in tanker voyage claims as they serve as formal records of disputes or inefficiencies. However, several challenges often undermine their effectiveness:

• Assumption of the Obvious: A common mistake is assuming that an issue is self-evident, leading to vague or incomplete LOPs. Every detail should be explicitly recorded, including times, actions taken, and any objections raised.
• Delayed Issuance: LOPs should be issued immediately when an issue arises. A delayed protest may lose its impact or be challenged as an afterthought.
• Failure to Address the Right Party: If the LOP is not properly addressed to the terminal, shipper, or charterer, it may be dismissed as irrelevant.
• Lack of Specific Evidence: Generalized complaints (e.g., "slow cargo operations") hold less weight than specific statements (e.g., "Cargo rate dropped to 300 m3/hr at 14:30 due to terminal valve restriction").
• No Acknowledgment from the Receiving Party: If the terminal or other concerned parties refuse to sign the LOP, it weakens the claim. While refusal itself can be noted, a countersignature strengthens the document.
• Unclear or Weak Wording: Strong and factual language is essential. Terms like "possible delay" or "some inefficiency observed" should be avoided in favor of precise wording like "cargo stopped from 10:15 to 11:45 due to terminal pipeline pressure issues."
• Improper Record Keeping: If the LOP is not properly logged and included in post-voyage documentation, it may not be available when needed for claims defense.

2. Pumping Log Issues & Pumping Performance Calculator

Most tanker charter parties include strict pumping requirements, often stating that the vessel must complete discharge within 24 hours or maintain a minimum pressure of 100 PSI at the ship’s manifold throughout discharge. Failure to meet these conditions can result in performance claims or disputes. Common issues in the pumping log that weaken a vessel’s defense include:

• Missing Pressure/Rate Changes: The log should record any fluctuations in pressure and rate, along with explanations. If the vessel was unable to maintain CP requirements due to terminal restrictions, this must be clearly documented.
• Vague Remarks: Instead of writing "as per terminal instructions," the log should specify the exact rate/pressure change requested and the reason for the adjustment (e.g., "Terminal requested reduction to 80 PSI due to back pressure").
• Lack of Terminal Representative’s Signature: Without a signature, the log may be disputed, making it harder to prove that terminal restrictions caused delays.
• Stripping Not Documented: Stripping is a critical phase of discharge, and any delays or inefficiencies should be recorded in the remarks column to justify additional time used.

Pumping Performance Calculator

The "Pumping Performance" formula is now widely accepted as the only reliable way to assess any under-performance by a tanker's pumps during cargo discharge. Based on straightforward physics, the formula can be used to determine the flow rates that may be achieved at different back pressures.

The logic is that the discharge pressure for a given system varies proportionally to the square of the flow rate. This can best be explained by an example:

If the bulk pumping rate is 500 mt/hour at 6 Kg/cm2, the rate at 7 Kg/cm2 can be calculated as:

500×(7.06.0)=540?mt/hour500 \times \sqrt{\left(\frac{7.0}{6.0}\right)} = 540 \text{ mt/hour}500×(6.07.0)=540?mt/hour

This formula is accurate as long as the differences in flow rate are not extreme and provided that an increase in back pressure does not result in significant vaporization in the suction lines to the pump.

Best Practices for Accurate Pumping Performance Assessment:

1. Record Accurate Start/Stop Times: Ensures precise efficiency calculation.
2. Document Terminal-Induced Restrictions: If delays occur due to shore-side issues, note them in the remarks column and obtain terminal acknowledgment.
3. Monitor and Adjust Pumping Strategy: Crew should be aware of CP limits and adjust stripping and pressure control accordingly.

By maintaining a well-documented pumping log and using the Pumping Performance Calculator, vessels can defend against performance claims and ensure compliance with CP requirements.