Understanding Moisture Readings in Hulls

Moisture intrusion is the primary enemy of fiberglass boats, especially those with cored hulls (balsa or foam). It can lead to core saturation, delamination, and severe structural degradation. This is why every pre-purchase survey includes a moisture meter inspection.

How We Detect Moisture

We use non-destructive, capacitance-type moisture meters (like the Tramex Skipper Plus) to scan the hull, deck, and superstructure. These meters send a low-frequency signal into the material to measure its dielectric constant. Water is highly conductive, so elevated readings indicate moisture.

What Do the Readings Mean?

• Dry / Low: Normal for sound fiberglass. No significant moisture detected.
• Elevated: Indicates moisture presence, potentially from condensation or minor leaks. Further investigation (percussion testing) is needed.
• Saturated / Wet: The core material is likely compromised. This is a serious issue that usually requires invasive testing (drill samples) to confirm rot or delamination.

Percussion Testing

We combine meter readings with "sounding" the hull—tapping it with a plastic hammer. A sharp, crisp sound indicates solid laminate. A dull, dead thud often points to delamination or wet core, confirming the meter's findings.

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