Rub Rail Repair

Do It Yourself!

Richard Strauss April 5, 2012

We’ve all done it. As active boaters we somehow or another at sometime or another managed to damage our rub rail. Since we’re only human and accidents happen, the following tips can be implemented as a basic guide to ensure proper repair. Constructed of highly durable, impact resistant materials, rub rails are typically available in rigid vinyl, semi-rigid vinyl, flexible vinyl, aluminum or stainless steel configurations. Although the primary function of a rub rail is to protect protruding portions of a boat’s hull from superficial damage, rub rails serve as an additional buffer between the harsh marine elements and the inner portions of your boat.

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Damaged rub rails are unsightly and can lead to unwanted water intrusion. Photo: FSF Mag

Rub rails are installed directly over a critical structural joint between your boat’s hull and deck liner that must remain watertight at all times. Therefore, in the event your rub rail has sustained significant damage, your first concern should be to determine whether the integrity of the joint beneath the rail has been compromised. In order to do so, you’ll first need to remove the damaged portion of the rub rail so a thorough inspection of the critical hull/deck joint can be made. After confirming that all joint fasteners are secure, inspect the surrounding gelcoat and fiberglass finish for cracks and/or fractures. If either is present, consider having a qualified technician perform the necessary repairs.

Although rub rail repair may sound straightforward, as always it is best to consult a reputable technician before undertaking a project of this nature for the first time.

After you’ve surveyed the damage, and assuming it’s only cosmetic, you’ll need to determine exactly what type of rub rail you’re working with. In today’s market, there are several types and configurations of rub rails that may appear on your vessel depending on its size and intended use. Some are simple one-piece PVC or vinyl strips, while others are two-piece systems consisting of PVC or vinyl rails with PVC, vinyl, or stainless steel inserts. Both designs are considered equally effective for most applications. However, two-piece systems are generally considered more aesthetically appealing and are a bit more costly.

Rub rails are fabricated with several different degrees of hardness and are applied to different types of vessels based on the vessel’s weight and intended use. If your rub rail is relatively soft and has been sliced, partially cut or gouged, repair will most likely require only a section of the rail be replaced. This often requires little more than a sharp utility knife, a tape measure and a tube of marine-grade sealant. Proceed by cutting out the damaged section of rail with clean 90° cuts at each end. Once you have removed the damaged section and determined how long the new section needs to be, finely sand and thoroughly clean the area. The replacement section should be measured and cut at exactly the required length.

The downside to sectioning in a new piece of rub rail is the potential for the new section to shrink in cold weather. Fastening a stainless steel screw at each end of the new section of rub rail will help prevent shrinkage. If you choose to do so, use high quality sealant on the threads of each screw. This will seal the screw holes, as well as help keep the fasteners from backing out with normal vibration.

In many cases, rub rails are installed as one continuous piece spanning the entire length of the hull, including the bow and transom. If yours is such, you will need to decide whether you’ll be happy simply sectioning in a new piece or whether you would prefer to replace the entire rub rail. With late model vessels, local boat dealers and boating accessory retailers should have access to rub rail kits directly from the OEM manufacturer.

For two-piece rub rail systems, the plastic or PVC inserts are usually one piece and are screwed at each end to minimize shrinkage. Therefore, whether you decide to replace one section of your two-piece rub rail or the entire rail, you will most likely need to replace the entire insert on a two-piece system. The exception to this would be if your rub rail incorporates a stainless steel insert. When this is the case, sectioning in a new piece of insert is usually quite simple.

Typically, stainless rail inserts come in 6, 12, or 18-foot sections. If only a portion of your existing rail is damaged, simply replace that section by removing the damaged portion of the old rub rail and installing the new section in its place. The final step when replacing a section of insert is to keep the seams of the insert offset from the seams of the rub rail.

If the rub rail is of a high durometer (harder), then a slice, partial cut or gouge can most often be sanded out and buffed for cosmetic purposes. When sanding imperfections, start with fairly aggressive 80 or 100 grit sandpaper. Then work the area with progressively lighter grits, all the way down to 600. Finish by buffing with a medium-grade compound until the shine matches the original rail.

After a rub rail has been repaired or replaced in sections or in its entirety, run a bead of marine grade silicon or UV protected urethane sealant along the top and bottom edge where the rub rail meets the deck. This will help keep dirt, grime and saltwater from getting behind the rail.

Although rub rail repair may sound straightforward, as always it is best to consult a reputable technician before undertaking a project of this nature for the first time. Review the damage and let your technician know how you plan to proceed. A professional may recognize something that you overlooked and may be able to guide you and/or keep you out of trouble.

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