IRC Review of Emerging Canting-Keel Configurations
London, 27 October 2026IRC continuously reviews significant design developments as they emerge within the fleet. Our responsibility is to ensure that different technical solutions are treated fairly and consistently, while allowing genuine innovation.
A recent review has identified an unusual canting-keel arrangement in which a more substantial proportion of the boat’s weight is concentrated in the keel bulb when compared to typical canting keel arrangements, the stiffness of the platform means that canting the keel produces a comparatively modest static list angle. For this type of configuration, the measured static response does not fully represent the additional righting moment and performance benefit available when sailing.
As a result, the current treatment can understate the benefit of the arrangement relative to other canting-keel configurations.
This is not a review of canting-keel yachts generally. IRC has rated canting-keel boats successfully for many years, and established configurations remain appropriately represented. The issue concerns a particular interaction between bulb weight, the static stability of the yacht and the measured list angle which is not fully captured by the current treatment. IRC considers this to be a valid and innovative development. The arrangement is arguably simpler than some other variable righting-moment systems and does not introduce unnecessary cost, complexity, intrusion into the yacht or operational burden. Our intention is therefore not to discourage the concept, but to ensure that its performance benefit is rated appropriately and fairly.
We also recognise that the performance of the yacht concerned cannot be attributed to this feature alone. It is the highest-rated and potentially fastest yacht in the fleet, is sailed by a strong crew, and benefits from a design developed to perform at the highest level, from rig down to hull and appendages. Any assessment of its results must take those factors into account. Nevertheless, the review has concluded that the present treatment does not fully reflect the contribution made by this particular canting-keel arrangement.
The canting-keel treatment will therefore be revised for 2027. In developing the revision, IRC has considered its effect across a broad range of existing boats and possible future designs. The objective is to address the identified anomaly while minimising changes to established canting-keel configurations that are already appropriately rated.
Owners and designers should also be aware that converting an existing yacht to a canting keel would almost certainly result in its Age Date being reset. The resulting rating implications should be fully considered at an early stage when evaluating any proposed modification.
IRC supports innovation and does not seek to favour or discourage particular design concepts. Where a development provides genuine performance benefits without imposing unnecessary complexity or cost, our aim is to recognise and rate those benefits fairly, allowing the design to compete on an appropriate basis within the wider fleet.
Notice issued by: Dr Jason Smithwick
Director of Rating
RORC Rating Office