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Rudder bulb / twisted rudder retrofit

vendor claim — not yet independently measured

A streamlined bulb on the rudder (often with a twisted leading edge) that fills the propeller hub vortex and smooths the flow behind the propeller, recovering energy and reducing drag.

2–6%
CO₂ emissions reduction
€120k–350k
indicative capex band (vendor/literature prior)
2–4 days
drydock required
14,642
candidate vessels (fitment unverified — equipment data cannot prove absence)

Which ships it suits

  • Segments: Bulk carrier, Chemical tanker, Combination carrier, Container ship, Gas carrier, General cargo ship, LNG carrier, Oil tanker, Refrigerated cargo carrier, Ro-ro ship, Vehicle carrier
  • Remaining service life: at least 5 years (payback must fit inside it)

Candidate vessels — worst CII band first

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Measured real-world outcomes

The reduction range above is a vendor claim. We continuously detect completed retrofits in shipyard-visit, equipment and EU MRV emissions data and measure the actual AER change. Measured results are published per measure once at least 30 controlled observations exist — until then, treat vendor ranges as ceilings: real-world delivery is consistently at or below the low end.