Question 1

How do I know if a gelcoat crack is cosmetic or structural?

Accepted Answer

Cosmetic gelcoat cracks (spider cracks, crazing) are surface-only and do not penetrate the underlying laminate. They appear as fine hairline patterns, often in stress areas like cleat bases or stanchion mounts. Structural cracks extend through the gelcoat into the fiberglass laminate — they are typically wider, may weep water, and often follow straight lines or radiate from hardware attachment points. Tap the area with a coin: a solid sound means intact laminate; a hollow or dull sound suggests delamination or core damage beneath. When in doubt, have a surveyor assess it.

Question 2

How much does fiberglass hull repair cost?

Accepted Answer

A cosmetic gelcoat repair (small chip or hairline crack) runs $200-$500. A structural fiberglass repair (through-hull damage, stringer delamination) ranges from $1,500-$10,000+ depending on the extent. Full gelcoat refinishing on a 40-foot hull runs $8,000-$15,000. Transom core replacement — one of the most common structural repairs on older boats — costs $5,000-$20,000 depending on boat size and construction. Osmotic blister repair and barrier coating runs $150-$250 per foot of waterline.

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