Dropping a keel looks like a big job, but sometimes it is the only way to truly see the keel-hull joint and the bolts. The decision rests on a survey finding; the work is planned with its sequence and check points.
When is it needed?
- A crack opening at the keel-hull joint, especially at the leading edge.
- A history of grounding, with cracking or separation in the internal floors.
- Rust, standing water or looseness around the keel bolts.
- When the bolts' age and material mean their inside needs to be seen.
The sequence
- Support the boat. The hull is supported separately, since the keel will no longer carry it.
- Measure and mark. Keel position and angle are recorded before removal.
- Removal. Bolts out, keel lowered.
- Inspection. Bolts, keel top, hull bottom and internal structure inspected in the open.
- Repair. Laminate and internal structure repaired; bolts and backing plates renewed if needed.
- Rebedding. The joint face is prepared, the keel refitted with sealant and the bolts torqued to the maker's value.
- Finishing. The joint is faired, primed and antifouled.
Check points
The inspection in the open after removal and the final check before rebedding are the two critical moments. Both are photographed; acceptance comes after relaunch, when the internal floors and bolts are seen to stay dry.
What we often see
- Opening at the keel-hull joint: A clear crack and paint separation along the keel joint, at the leading edge.
Why a keel drop may be needed
A keel drop comes up when survey or maintenance suggests a problem at the keel joint: a crack at the joint that reopens after every launch, advanced corrosion on keel bolts, signs of internal damage after a hard grounding, or bolts that have not been checked for many years. Dropping the keel is the way to see these problems directly and fix them for certain.
The process
- Preparation. The boat goes into a suitable cradle, the keel is supported from below and a safe lowering arrangement set up.
- Removal. Nuts are slackened from inside and the keel lowered under control.
- Inspection. Bolts, the keel's top face, the hull stub and the internal structure are examined; bolts are replaced if needed.
- Refitting. Mating faces are cleaned, sealant applied and the keel refitted.
- Torque. Bolts are tightened to the maker's torque and sequence, and recorded.
What sets the cost
Keel weight, number and type of bolts, access to the internal structure and whether bolts are replaced set the cost. If the bolts are cast-in or the structure needs repair, the job grows. The written quote asks for unit rates for these uncertainties.
Afterwards
After refitting, the joint and inner floor are watched for leaks at launch and on the first passages; bolt torque is rechecked at the maker's recommended interval.
After a grounding
A hard grounding does not always mean a keel drop, but it always means a careful inspection of the joint, floors and keel bolts before the boat goes back to sea.
Not every crack needs a keel drop
A fine line at the keel joint is often just a surface crack in filler and paint, with no structural meaning. A keel drop comes up when there are further signs: the crack reopening at every haul-out, movement or damp in the inner floor, corrosion on the bolts. The survey makes that distinction and bases the decision on measurement.
Photos of the nuts serve as a reference.