Sounding Tape Weights

Admin
3 days ago
2 min read

Updated: 2 days ago

Sounding Tape Weights – Why the Type Matters for Ballast and Fuel Tanks

Using a sounding tape is routine work onboard — but using the wrong weight or worn-out cone can slowly create major sounding errors, especially in ballast and fuel tanks.

🎯 Why This Matters

Many ships use conical weights on sounding tapes for easier entry into the pipe. But over time, conic tips can damage the pipe’s datum plate, especially when dropped too hard or used repeatedly without care.

Once the datum plate is scratched or indented, soundings will always show more centimeters than real — causing ballast, fuel, or even draft survey errors.

📐 Types of Sounding Tape Weights

Most vessels have one of the following:

⚫ Conical Weight (Pointed End)

Common on new tapes or used for narrow pipes.
Easy to insert, but high risk of damaging datum plate over time.
Not suitable for frequent ballast/fuel tank soundings unless handled very gently.

Flat or Cylindrical Weight (Non-Conic)

Safer for regular tank sounding.
Rests flush on the datum plate.
Less chance of creating indents or scratches.
Often better for accurate readings over time.

⚠️ Common Issues with Conical Weights

Repeated contact creates a dent in the datum plate.
Increased sounding readings (false cm added).
Errors accumulate unnoticed — especially problematic during:
- Fuel ROB calculation
- Ballast exchange control
- Draft survey intake/discharge figures

✅ Best Practices for Deck Officers

Use flat-end weights for all regular ballast and fuel tank soundings.
If using conic weight, do not let it drop — lower gently to avoid hitting the plate.
Regularly inspect tape and datum plate condition during tank inspections.
If a dent is found, record correction or switch to corrected datum.
Inform C/E or Master if a plate is damaged — this is especially important for FO/DO tanks and ROB reports.

📌 Maintenance Tip

If your tape tip becomes loose or deformed:

Replace the weight immediately.
Avoid makeshift fixes — inaccurate weight means inaccurate level.
Never mix fuel/ballast tapes to avoid contamination.

🧑‍✈️ Real Practice Matters

A small dent today can lead to 10+ cm error tomorrow — that’s tons of cargo or fuel on paper. Take care of your equipment and always use the right tool for the job.