Boat Painting Tips: Avoid Print-Through and Paint Failure

Painting a vessel’s hull or deck is a significant undertaking—financially and logistically. It requires the unstepping of spars, the removal of hardware (ideally), and the production of copious amounts of dust, which means the cabin needs to be sealed tight. Even then, some dust always makes its way into interior or deck locker spaces, necessitating a deep cleaning.

I managed a boatbuilding and refit yard for 11 years. We routinely painted hulls, decks and spars, primarily using traditional two-part paint. In many cases, the hull color was being changed, and it was the rare exception when an owner opted for a light or neutral color. Almost invariably, folks wanted the snazzy dark colors such as super jet-black, vivid red, aristo blue, jade mist green and, of course, ­Stars-and-Stripes blue.  

It’s hard to deny that these colors look great. However, I tried in earnest to talk customers out of them. Other than aesthetics, there really are no advantages to dark colors, unless you cruise exclusively in high latitudes and are looking for a solar boost to warm up the cabin. 

Changing a hull from a light or neutral color to a dark color increases the surface temperature considerably. I conducted a series of tests one summer: Side by side, a light-gray hull measured 90 degrees Fahrenheit, while black and dark blue hulls measured 130 degrees Fahrenheit. Not only does this increase the cabin temperature—and the load on the HVAC—but it also leads to a phenomenon known as postcuring and print-through.  

In essence, when a hull’s color is changed from a light to a dark color, the resin cures more than it has cured previously. In doing so, it shrinks slightly. The warp and weft of the fiberglass fabric immediately beneath the surface or, worse still, the checkerboard pattern of core blocks beneath the outer fiberglass skin, often become visible—printing through the resin. It’s unsightly, to say the least, and the opposite of a paint job’s goal. 

Print-through can be prevented during the ­construction process. After the fact, it’s costly to correct. For this reason, I’m with legendary Capt. Nathanael Herreshoff, who reportedly said, “You can paint a boat any color you like, but if you paint it anything other than white, you are a fool.”

Another consideration is hardware. It’s critically important to understand the details of any estimate for a paint job, including whether hardware will be removed. Hardware removal adds cost; however, in my ­opinion, it’s nearly always worth the expense.  

In my experience, the longest-­lasting paint jobs are achieved when the coating is contiguous, and that can happen only with the removal of hardware. If hardware is not removed, then the number and length of seams grow exponentially. Each seam can become a toehold for paint failure. 

When the hardware is replaced, it should be sealed with ample bedding and plenty of “squeeze out,” meaning excess bedding that is pushed out from around the entire perimeter of each piece of hardware. This practice ensures that paint, which is invariably damaged by the hardware as it is installed—even if the damage is invisible to the naked eye—is sealed from water penetration and lifting.

Steve D’Antonio offers services for boat owners and buyers through Steve D’Antonio Marine Consulting.

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