You need to find a surveyor
and yard who have some idea what they are talking about. If, as you said earlier, the moisture readings were made on antifouling bottom paint
, then the person making them has no idea what they are doing. You cannot take moisture meter readings on bottom paint
. The bottom paint
must first be completely removed. Antifouling paint will give false positive readings every time.
Most moisture meters work by measuring the relative conductivity of the material in question, which is why moisture meter readings are relative and taken on multiple scales, ie a wood scale and an FRP scale. Because wood has different base conductivity than fiberglass
. Obviously any metals in the substrate will read as moisture, as metals are much more conductive than fiberglass
or wood. Antifouling bottom paint has copper in it, which is highly conductive on a relative scale. Hence the false positives. Any surveyor
should know this, as should any yard. I would not let anyone who didn't know this work on my boat in this regard.