The World Sailing Offshore Special Regulations (WSOSR) Appendix L states that a structural inspection of the keel and rudder by a qualified person shall be conducted on a bi-annual basis for Category 1, 2 and 3 offshore racing.
In the UK, this effectively means that a keel and rudder inspection is required for JOG, RORC, and other organisations offshore racing events.
Keel and rudder inspections are also a prudent safety check for anyone planning to cruise offshore.
Lateral movement
The requirements are for the keel to be checked for corrosion and for deflection.
The test checks that there is no movement at the keel join – so when a lateral force is applied, the keel and the hull move as one, as illustrated in the above photo of a Sigma 38 during a deflection test at Deacons Marina, Bursledon.
Structural issues
Additional inspection internally and externally is looking for any structural issues in the surrounding area of the hull and the internal reinforcement.
This includes to the transverse floors, or more commonly on modern vessels to the internal tray matrix / grid / liner (the description varies between boatyards as well as the manufacturers).
Rudder
Solent Marine Surveys checking the torque on the keel stud nuts
The rudder likewise is tested for deflection, and the internal area of reinforcement is also checked, using hammer sounding together with a visual inspection.
Torque on keel studs
The final test is to check the torque on the keel stud nuts. This is done to ensure that all nuts are sufficiently tight to keep the upper surface of the keel tight against the hull.
We can check torques for keel nuts up to 55mm ATF, corresponding to M36 sized metric keel studs.
A lack of sufficient torque can lead to potential movement and thus weakening of the keel studs, as well as the surrounding structure.
Contact us
We often see an uptick in the requirement for these checks in Fastnet Race years, and from people planning to participate in the ARC Rally and similar.
While in certain cases the owner can “self-certify” the inspections, generally most people are not qualified to do this, and ask a qualified marine surveyor to conduct this inspection for peace of mind.
The checks are required bi-annually or after any grounding.
Please contact us at info@solentmarinesurveys.com if you would like us to provide this essential inspection for you.