| Scenario | Dredging h | Transit h | Standby h | Main Load | Fuel (L) | Avg (L/h) |
|---|---|---|---|---|---|---|
| High production, short move | 7.0 | 1.0 | 0.5 | 0.80 | 1,410 | 170 |
| Moderate production, long transit | 5.0 | 3.0 | 1.0 | 0.70 | 1,180 | 131 |
| Maintenance shift, heavy standby | 2.0 | 1.0 | 5.0 | 0.50 | 640 | 80 |
L/h = kg/h ÷ Fuel Density(kg/L)
+ (Loaded Rate × Transit Factor × Transit Hours)
+ (Loaded Rate × Standby Factor × Standby Hours)
- Enter dredging, transit, and standby hours for the shift.
- Set fuel density, price, and optional CO₂ factor.
- For each engine, choose SFC or direct flow method.
- Use transit and standby factors to reflect lighter operation.
- Press Calculate to show results above the form.
- Download CSV or PDF to share the summary.
Dredge Fuel Planning Guide
1) Why fuel forecasting matters on dredging projects
Fuel is often the largest variable operating cost for cutter suction, hopper, and backhoe dredges. A small planning error can ripple through production, tug support, and disposal logistics. Using a structured estimate for dredging, transit, and standby helps align shift targets with realistic burn rates.
2) Typical diesel density and what it changes
Diesel density commonly ranges from 0.82 to 0.86 kg/L, changing with temperature and blend. Because SFC calculations convert mass to volume, a 0.02 kg/L shift can move estimated liters by a few percent. If you have lab data, use it; otherwise keep density consistent for comparisons.
3) SFC ranges and what “good” looks like
Modern marine diesels may operate near 190–230 g/kWh depending on engine family and load point. Lower SFC means better efficiency, but the best number is the one that matches your actual duty cycle. Record hours and refuels for two weeks to calibrate the input values.
4) Load factor as a production indicator
Load factor links power demand to production intensity. In practice, dredging loads can sit around 0.60–0.85 when cutting and pumping steadily, and drop during light slurry, re-positioning, or partial pipeline restrictions. Adjust load with real data from engine monitoring or operator logs.
5) Transit and standby factors for realistic shifts
Transit and standby rarely match full dredging load. Multipliers such as 0.50–0.75 for transit and 0.15–0.40 for standby are common starting points, then refined by logs. Separating phases prevents inflated totals when travel time or waiting dominates the day.
6) Cost and carbon reporting you can defend
Cost is computed from liters times the unit fuel price, allowing quick bid sensitivity checks. For carbon, many teams use a diesel factor around 2.68 kg CO₂ per liter. Keep your chosen factor consistent with client reporting rules and document it in the Notes field.
7) Example benchmark using this model
Consider a main engine rated 900 kW at 0.75 load with 210 g/kWh and density 0.84 kg/L. The main rate is about 169 L/h. Add a 200 kW auxiliary at 0.65 load and 230 g/kWh for roughly 36 L/h. Loaded dredging burn becomes ~205 L/h before applying transit/standby factors.
8) Field workflow for continuous improvement
Start with conservative assumptions, then compare predicted liters to actual refueling totals. Update one parameter at a time: first hours by phase, then transit/standby multipliers, then SFC or flow rates. Over a month, the estimate typically converges into a dependable planning and reporting tool.
FAQs
1) Should I use SFC or direct flow?
Use SFC when you know rating, load, and typical efficiency. Use direct flow when you have reliable measured liters per hour at the same operating condition. Calibrated flow logs usually outperform guessed SFC values.
2) What if I have multiple auxiliaries?
Combine them into one equivalent auxiliary by summing kW ratings and using an average load factor, or use a single measured auxiliary flow rate. Keep notes on how you aggregated the equipment for auditability.
3) How do I estimate load factor without sensors?
Start from operator experience: heavy cutting often sits near 0.75, light pumping near 0.60, and repositioning lower. Then back-calculate load by matching predicted liters to refueling totals over several shifts.
4) Why are transit and standby multipliers needed?
Because engines rarely run at the same demand outside production. Multipliers translate your loaded dredging rate into lighter duty conditions, preventing overestimation when travel, warm-up, waiting, or minor downtime consumes a large portion of the shift.
5) Does fuel density really matter?
Yes, when converting mass-based SFC into liters. Using 0.82 versus 0.86 kg/L can shift the volume estimate by several percent. If you only compare scenarios, using one consistent density still improves decision quality.
6) How should I set the CO₂ factor?
Use the factor required by your client or internal reporting standard. If none is specified, keep one consistent value across projects and record it in the Notes field so reports remain traceable over time.
7) Can I use this for weekly or monthly totals?
Yes. Enter representative daily hours and multiply results externally, or run separate scenarios for different shift patterns. The history table and CSV export help summarize multiple runs and build a simple reporting trail.