Pre-Shrouded Ducts
Improving inflow conditions and reducing resistance ahead of the propeller.
Overview
A pre-shrouded duct is installed ahead of the propeller to recover energy from the wake field, improve inflow uniformity, and mitigate cavitation and noise. This reduces propeller loading and increases overall thrust efficiency across various operating conditions.
How It Works
- 1The duct is mounted on the hull ahead of the propeller, accelerating and straightening the incoming flow.
- 2By recovering energy from the wake field, the duct reduces the rotational energy loss that would otherwise occur at the propeller tips.
- 3The improved inflow uniformity lowers propeller loading, mitigates cavitation and noise, and increases overall thrust efficiency.
- 4CFD simulation and model-scale tank testing validate each design before installation, ensuring predicted savings are delivered at sea.
Key Benefits
- ✓Improving inflow conditions and reducing resistance
- ✓Enhancing propeller thrust efficiency
- ✓Mitigating cavitation and noise for indirect energy saving
- ✓Recovering wake energy to improve comprehensive efficiency
Applicable Vessel Types
- ▸30,000–82,000 DWT Bulk Carriers
- ▸85,000–120,000 DWT Mini-Cape Carriers
- ▸170,000–182,000 DWT Capesize Carriers
Specifications
- Fuel Saving
- 2–8%
- Delivery Cycle
- 6–12 weeks per ship
- Vessel Types
- Bulk carriers, Cape-size, Mini-Cape
- Class Approval
- CCS, ABS, BV, DNV, LR, RINA, NK, KR, RS
FAQ
What fuel saving can I expect from a pre-shrouded duct?
Field data from 70+ retrofitted vessels confirms fuel savings of 2–8%, depending on hull form, operating profile, and draft conditions. Savings are verified by sea trial.
How long does installation take?
Delivery cycle is 6–12 weeks per ship, including design, manufacturing, and installation. The duct can be installed during dry-docking with minimal modification to the hull.
Which classification societies have approved this design?
Our pre-shrouded duct designs are approved by CCS, ABS, BV, DNV, LR, RINA, NK, KR, and RS — covering all major class societies.
Can the duct be retrofitted to an existing vessel?
Yes. The pre-shrouded duct is designed as a bolt-on retrofit and can be installed during routine dry-docking without major hull modification.
Success Cases
70+ vessels retrofitted across bulk carrier, mini-cape, and capesize segments
180,000 DWT Capesize Bulk Carrier (LR) — comprehensive fuel saving over 6%