Keel and rudder fins fail for various reasons, and periodic visual inspections by an appropriately qualified person can do to a lot to mitigate this risk.

The reasons behind keel fin and rudder failure include damage from groundings and collisions, or inadequate maintenance, even sub-optimal design or manufacturing, or attachment to the hull. The yacht types losing keels and rudders range from cruising to high performance racing yachts and from newly built, to old.

Crews need to be aware of the associated danger of keel detachment and have preventative procedures in place to reduce the risk. Visual inspections are critically important.

The periodic inspections may capture visual signs (cracks, movement, corrosion, loose keel bolts not tightened to the correct torque, loose or irregular rudder bearings) that may indicate a potentially serious problem. These might be identified by regular inspection of the keel attachment area and by performing a tip swing or deflection test.

For the tip swing test, the yacht is suspended with the keel off the ground/cradle. A member of the inspection team braces themselves and attempts to move the keel while the inspector looks, both from the outside and at the inside (keel floor) of the yacht, for movement (opening and closing of any cracks) at the keel/hull interface.

Some inspections that can be done in the water:

• Keel Bolts can be checked for excessive corrosion. Torque them to the manufacturer’s specifications.
• Internal Hull Structure can be checked for signs of structural failure and/or laminate separation especially in the area around the keel structure, keel floor and other stress points

Some inspections for when the boat is out of the water:

• External Hull Condition can be checked for hull stress cracks around leading and trailing edge attachment point to structure, hull appendages and keel sumps. Also inspect the keel/hull interface for signs for damage by tip swing test.
• Rudders can be checked for cracking of the rudder bearing/hull assembly. The rudder can also be checked for integrity by tip swing test.

It is expected that once any visual sign of a potentially serious problem is noted, a more detailed investigation would be undertaken or it would just get repaired.

Since January 2022, Special Regulation 3.02.4 has required boats competing in category 1, 2 and 3 races to have keel bolt checking and retightening and other visual checks done every 24 months. Appendix C to the Special Regulations goes on to provide detailed guidance to the person performing the checks.

These rules came about because of a number of keel failures, some of which catastrophically and tragically ended in fatalities.

For the Special Regulations, click here.
The safety incident reports can be found here.

By Glen Stanaway