I hauled my boat for bottom paint. The hull looked like it had the pox—thousands of tiny blisters. The yard manager said, “Osmosis. The fiberglass is delaminating. Needs a full peel and re-glass. $12,000.” I called my insurance. “Denied. That’s maintenance.”
Key Takeaways
- Osmosis is “Gradual Deterioration”: Insurance covers sudden and accidental loss. Osmosis happens slowly over years as water penetrates the gelcoat. It is universally excluded as “wear and tear” or “inherent vice.”
- Consequential Damage: Some high-end policies (Pantaenius) might cover consequential damage resulting from a latent defect, but rarely the blister repair itself.
- The Survey Trap: If you buy a used boat, the surveyor checks for high moisture readings. If you skipped the survey and bought a blistered boat, that’s on you.
- Prevention: Barrier coats (epoxy) are maintenance costs you must pay to prevent this.
The “Why” (The Trap)
The trap is “Inherent Vice.”
Fiberglass naturally absorbs water over time. It is a known property of the material. Therefore, it is not a “fortuitous” (unforeseen) event.
Just like insurance doesn’t pay for rusty steel, it doesn’t pay for blistered fiberglass.
The Investigation (I Asked Yards)
- The Repair: A full blister job involves peeling the gelcoat, drying the hull for months, and re-glassing. It is expensive and takes the boat out of commission for 3-6 months.
- The Exception: If the delamination was caused by a manufacturing defect on a new boat, the hull warranty (from the builder) covers it, not insurance.
Comparison Table
| Issue | Hull Warranty | Insurance |
| Blisters (Year 1-5) | Yes (Usually) | No |
| Blisters (Year 10+) | Expired | No (Wear & Tear) |
| Delamination from Impact | N/A | Yes (Collision) |
Step-by-Step Action Plan
- Get a Moisture Meter Survey: Before buying any boat, have the surveyor map the hull moisture.
- [IMAGE: Photo of a moisture meter reading ‘High/Wet’ on a boat hull]
- Apply Barrier Coat: If you have a new boat, pay the $2k now to epoxy barrier coat the bottom. It prevents the $12k repair later.
- Don’t File a Claim: Filing a claim for osmosis will just get you a denial letter and a “Claim Incident” on your record. Don’t bother.
FAQ
Can I just paint over them?
You can, but they will pop back out and eventually weaken the laminate structure.
Does ‘Latent Defect’ coverage help?
Latent defect coverage usually pays for the damage caused by the defect, not the defect itself. E.g., if the hull splits open due to a bad layup, they pay for the salvage, but maybe not the new hull.