Article by Capt. Steve Katz
The Shiny Side
While many of my past columns hovered around electrical, mechanical and electronic topics, these systems are all contained within the fiberglass, wood or combination of materials that forms the structure of the boat.
How your boat is built, the materials used, assembly process and finishing methods have a lot to do with how the boat should be maintained and repaired.
Many boats are built within a production line in a factory, similar to how automobiles are built. The hull structure rolls on a wheeled trolley or similar device, through the factory while it is progressively being built and assembled until a finished boat is ready to leave the building.
Years ago, on a visit to the Ocean Yacht factory in New Jersey, while touring the factory floor, we were asked by the staff if we could help push the partially completed hull, contained in a wheeled cradle, across the shop to the next production area. Times have changed for many boat manufacturers and the process is much faster with more automation, though some lower volume boat builders still do it the same way as observed years ago. Many custom boat builders keep the hull in one location and bring the structural components, materials and workforce to the boat.
Why is this important? To properly maintain and repair your boat, knowing the materials and construction methods will determine how the boat should be repaired or maintained.
Unlike mass produced automobiles that have detailed service manuals that provide assistance when service is needed, boat repair often relies upon the skills and expertise of a marine technician. It is important to choose a company or technician that is familiar with the needs of your boat. If you are not sure on how your boat was built or the materials used, it is best to contact the manufacturer or other reliable sources to gain that information.
Even if you or your crew are performing a “do-it-yourself” repair, it is still important to have a thorough understanding of your boats design and construction.
One example is the basic structure. Most boat are built with fiberglass, but that term is a little too general. What most people call fiberglass is properly referred to as Fiber Reinforced Plastic (FRP). A fiberglass boat is made from glass fiber or other similar materials combined with a resin (plastic) to create a strong but light composite structure. Those materials include glass-fiber, carbon-fiber, non-woven glass or carbon mat combined with a resin such as polyester, vinyl ester or Epoxy.
If major repairs or modifications are needed, the same materials or compatible materials should be used in the repair process that are equivalent to the materials used in the original production process. We don’t often see these materials since they are contained under a coating of gelcoat or paint. Even a visual examination of the construction materials may not be enough to differentiate some of the above materials.
When it comes to small modifications, such as drilling a hole or cutting part of the boat for the installation of new equipment, knowing what you’re cutting through, and if there is wood, foam or solid fiberglass in the construction is important to properly prepare, seal and strengthen, if necessary, the modification to preserve the original structure of the boat.
When it comes to the shiny hull and topside surfaces on your boat, you need to know if the surface is painted or gelcoated. These similar, but different, surfaces have different cleaning, polishing and repair techniques. Using the wrong products or techniques may cause undesirable results.
How do you know if the finish of your boat is gelcoat or paint? Most production boats are built in a female mold and the first step is to spray the mold with gelcoat. Afterwards, the rest of the materials are added in layers to form the boats structure. Once pulled from the mold for further assembly, the outside surface is finished. With a jig-built (cold-molded) boat, the structure is built first and the outside surface is often painted (not gelcoated) as the last step in the building process.
Many gelcoated boats are painted later in life since the shine of the gelcoat may have permanently dulled or the boat is painted to change it’s color. It’s rare for a boat to be re-sprayed with gelcoat, though it can produce nice results with long-term shine and protection.
Another way to tell if your boat is painted or gelcoated is to examine the area after damage has occurred. If the surface color is the same from the surface to the fiberglass structure, then it is most likely gelcoat. If the surface color is thin and reveals another color or material under the surface color, then the boat is probably painted. A gelcoat finish is much thicker than paint, generally 15-30 mils (.015”-.030”) thick and paint is about 5 Mills (.005") thick. The thick gelcoat allows you to regularly compound, polish and buff the boat without worrying about wearing through the finish quickly as compared to a painted boat.
Learning about your boats original construction will help guide you in the necessary maintenance and repair techniques that will preserve your boat for years of enjoyment.
Captain Steve Katz is the owner of Steve’s Marine Service and holds NMEA, AMEI and NMEA2000 certificates along with ABYC Master Technician certification and factory training from many manufacturers. To reach Steve, call 410-231-3191.
