Hull Repair Surprise: The Epoxy Filler Failed #shorts

Kris Fothergill inspects the underwater surfaces of the Leopard 46 catamaran Happy Days after discovering unexpected structural defects along the centerline seam. Having previously hauled out the vessel at Rebak, Malaysia to strip the hull back to the gelcoat and check for osmotic blistering, the crew of Sailing with six did not expect to find spongy hollows in the fiberglass laminate.

Discovering Soft Spots in the Hull

While checking the underwater profile, Kris discovered that a household butter knife could penetrate directly into the seam. He admitted, “I’ve just dug a hole in our hull with a butter knife, and that should not happen.” A closer look confirmed deep voids where the seam filler had completely lost adhesion to the fiberglass cloth underneath.

Confronted with the structural flaw, the team assessed the depth of the void along the centerline. Observing the flaking material, Kris remarked, “That is not good what we just saw.” The filler peeled away cleanly from the laminate instead of remaining bonded, exposing the underlying hull seam to potential water penetration.

Identifying Improper Filler and Grinding Back

The failure stemmed from the material applied during their previous yard visit. The yard had mistakenly used an improper fairing compound rather than true marine-grade epoxy. As Kris explained, “Below the waterline, epoxy filler is the standard because it bonds properly to the fiberglass and keeps water out.” Standard fairing compounds may appear smooth upon initial application, but they deteriorate over time in submerged conditions.

To rectify the issue, the crew engaged boatyard professionals to buzz back the centerline seam with grinders. The team planned to lay glass in sections where needed and rebuild the seam with G-Flex marine epoxy, ensuring an impenetrable bond along the hull.

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