Visual inspection.

Most keel checks are visual inspections. Whether it be part of annual maintenance, inspection after collision or grounding, or to take part in organised races, some form of visual inspection is undertaken. The areas that are generally tested are the hull structure supporting the keel, the keel bolts anchoring the keel to the hull, and the external connection of the keel to the hull. Based mainly around these areas, Marine surveyor’s will have devised their own tests (potentially driven by insurers) for recreational sailors.

Keel boats racing in Category 1-3 races must undertake a Keel and Rudder test See Further Reading The test must be carried out by a qualified person. “The definition of a “qualified person” varies from “a designer, builder or marine surveyor” to an experienced boatyard boss where the boat is hauled”See Further Reading

Non-Destructive Testing (NDT)

“NDT stands for Non-Destructive Testing. It is a wide-ranging group of techniques used to evaluate the properties, integrity, and quality of materials, components, and structures without causing any damage to them…… The primary objective of NDT is to inspect and assess the condition of an object or material without altering its functionality or structural integrity.” See Further Reading

If you are looking to purchase a boat or are maintaining your own boat, and get a standard Marine Survey, it is highly unlikely, that NDT testing would be used by the surveyor. NDT is more likely to be used to avoid removing the keel. Removing a keel often requires considerable cost and labour, specialist tools and expertise, and is not a DIY job for most boat owners or satisfactory for insurers. NDT testing is primarily used in the maritime world in the “big ships” area.

Our research and discussions indicates that most marine surveyors who carry out NDT on yacht keels have come from the “big ships” area and have adapted the tests to suit the specific problem to do with yacht keels.   There are very few specialists NDT “keel testers” – who carry out keel tests as their core business and no standard testing protocols with NDT for keels. when you have your Marine Survey done ask if they can do or arrange for NDT as part of the inspection.

NDT testing is mainly applicable to the things we can’t see in the keel inspection process including;

•Hidden damage from groundings or collisions may not show externally.
•Fatigue over time can lead to micro-cracks that grow unnoticed.
•Environmental exposure (saltwater, temperature changes) accelerate degradation.

NDT testing is of greatest value with keels that suffer from weld fatigue, which won’t be picked up by visual testing. Most conventional tests for keels focus on the way the keel is attached to the boat (hull integrity, keel bolts etc) and is based on mainly on visual inspections. (as outlined above)

With NDT testing for all keel boats, there is not one specific test or piece of equipment that covers keel testing. Thorough testing therefore can be time consuming and costly, and NDT testing isn’t normally part of the annual maintenance regime for most boats.

Many of the test results lie in the skill of the operator, the experience of the shipwright, and the knowledge of what test is appropriate for what keel, and the damage it may have sustained. 

Further Reading

Keel and Rudder Inspection Form Australian Sailing Website.

Remember to check your Keels and Rudders World Sailing World Sailing.2023.

Australian Institute for Non- Destructive Testing. AINDT website.

Checks to stay upright”. Published Thu 28 Nov 2024 AS

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