Last week, we talked about engine hours and how important—or less important—the number can be. If the engine is in good shape and maintenance is carefully documented, the next item of worry are the moisture meter readings determined through survey. For some people, high moisture readings are absolute showstoppers, while for others, they garner a mere shrug. Here again, knowledge is power!
Fiberglass is not a waterproof material, and eventually water molecules can find their way into the pores of the material. As build techniques and materials improve over time, the degree to which these molecules gain entry is minimized, but can’t be eliminated. If you are looking for a boat that is older than about 10 years, there is a very good chance that moisture readings will be higher than when the boat was factory fresh. What that means for you depends on your level of comfort. Let’s break this down into general categories: Very High Moisture, Moderate Moisture, and Elevated Moisture.
Very High Moisture Readings
In situations with very high moisture readings, there’s likely rot in the coring material and associated delamination. This is the debonding of the fiberglass skins from their structural reinforcing material, and the remedy is to cut out the rotten portion, replace the coring, and re-laminate the section. This can be expensive to repair properly, but not impossible. In other words, depending on the area(s) affected, the boat can be repaired. The photos below show an anchor locker hatch on my boat that was rotten and in the advanced stages of delamination. The surveyor found the area, and I had a nice winter project ahead of me!
Moderate Moisture Readings
With moderate moisture readings, there is enough moisture to warrant keeping an eye on the area, and some localized repair may be necessary. Often it occurs on deck where hardware is bolted down. The bedding material under the hardware is a life-limited seal and needs to be refreshed every few years. Otherwise, moisture ends up seeping through the bolt holes and eventually getting to the coring. Choosing the correct sealant for the job is paramount, as there is no one-size-fits-all product for the varieties of materials bedded to the deck. Plastics, woods, and metals all behave differently and require the correct sealants for proper bonding. Better boat building techniques remove coring in areas where hardware is bolted down, opting to either reinforce the area with metal backing, or drill the holes through solid fiberglass. You can do this yourself by removing the hardware, over-drilling the holes, and filling them with thickened epoxy. When you re-drill the holes, you’ll be in solid material that cannot rot. I did this on my boat and sleep wonderfully at night!
Elevated Moisture Readings
Lastly, the elevated moisture reading is a pretty common occurrence. Take care to know the extent of the moisture and have a plan to keep it in check. If the area is below the waterline, these areas should be monitored for possible blistering down the road. Though we don’t suffer from blistering these days to quite the same extent that we did 30 years ago, it can be a big job if they get out of hand. Again, proper maintenance can keep moisture readings in check for a long time.
Your surveyor has precision instruments to take moisture readings, and these tools are usually sent out for regular calibration/recertification. An accredited surveyor can be vital in identifying areas of higher moisture and finding the possible entry point(s). Trust their expertise, and keep in mind your level of comfort if repairs are in order. If you want to keep tabs on moisture on your own, you can purchase a moisture meter to keep with your tools. Practical Sailor magazine recommended a reasonably priced model made by Klein Tools, and I added one to the bag. You’ll see it in the pictures. Though not the pro-level tool that your surveyor uses, it is handy and accurate enough to give you solid perspective on where your moisture levels stand.
Keeping a boat shipshape is a process, but with a good game plan, a proven routine, and some basic tools, you can keep little jobs from becoming big ones. In addition, you keep your vessel’s value high, reduce the number of maintenance surprises, and ultimately, enjoy your time on the water more fully.