Rub(rail) Your Boat the Right Way

Posted: January 1, 2014

Is it time to replace an unsightly rubrail? Here’s how.

By: Capt. Wilson J. Sheppard

For quite a while, my wife has patiently allowed my 16-foot-long Duffield project to take up half of our two-car garage. In a symbolic gesture of getting it started, I decided to replace the boat’s rubrail.

Despite its unassuming appearance, the rubrail actually serves two important purposes. One, it is used to conceal the area where the boat’s deck is joined to the hull. Two, since most boat hulls widen with height (known as flare), the rubrail usually sits on the widest part of the boat and, consequently, is the first point of contact when the boat encounters a tall structure (e.g., other boat, piling, seawall, wife). The latter is my true inspiration for this project.

Whatever your inspiration, here’s how you can add a new rubrail to your boat.

Off with the Rail

The rubrail is a two-part fixture with a rail and an insert. The rail is secured to the boat with screws or rivets, and the insert slides or clips into the rail. Most rubrails are terminated on the transom with end caps. Once the end caps are removed, you have to slide the insert off the rail or pry it out with a flathead screwdriver and then remove the fasteners.

Before removing your existing rubrail, use a pencil to lightly trace the top and bottom of it, which will help you position the new rail and install it straight.

My boat is styled like a runabout with minimal flare. At the bow, two screws and some type of compound secured the rope insert (1). On the transom, one screw on each side held the rope in place (2). After removing these four screws (3), I was able to simply pull the rope out of the rail (4). Once it was removed, the mounting screws were accessible (5). A mere 78 screws later, I had the rail completely removed.

Choosing a new Rail

Three important factors to consider when purchasing a rubrail are the system’s material, height and length. Aluminum, vinyl and stainless steel are the most popular materials. Vinyl cushions better against impact, but aluminum and stainless steel last longer. Select a replacement rail that is similar in height to your current one. A smaller rail may expose the deck-to-hull seam. A larger one may overhang the area. If your boat doesn’t have a rubrail, use the following formula to determine the length you need: (Boat Length x 2) + Beam Measurement + Extra. The amount of extra rubrail will depend on how far you want it to extend across your transom. You can always cut it down to size.

My boat had a 1 7/8-inch rigid vinyl rubrail with a 1-inch rope insert. Since I am more interested in aesthetic appeal than fending off close-quarter encounters, I planned to keep the rope-style rubrail. Using the formula, I calculated that I needed 38 and a half feet of materials. In the spirit of “measure twice, cut once,” I put a tape measure on my original rubrail: 37 feet. Shopping online, the replacement materials for my project came in under $425.

Instead of buying parts individually, you can buy a kit that includes everything you need for installation. For example, Taco Marine has a 70-foot semi-rigid rubrail kit for less than $400.

Rubbing it In

To make sure you have a solid foundation to secure the rail, do not use the screw holes from the previous installation. Fill them with a marine sealant and allow plenty of time for it to cure. Gently use a paint scraper or sandpaper to remove old and excess sealant. A smooth installation surface will allow the new rail to sit flush against the hull (6).

Your new screw holes should be about 6 to 8 inches apart. Mark their locations with arrows along the edge of the pencil outline. Also, find and mark the middle of the entire length of rail. Have someone hold this point at the bow. If your rail does not bend easily, use a heat gun or a hair dryer to slowly heat it until it bends around the bow.

Use a drill bit smaller than the mounting screws to make pilot holes along the center of the rail at the indicating arrows. Since you already have the power drill handy, use it to install the screws, too. Coat each screw with sealant to ensure each hole is watertight. Be careful not to damage the rail or hull while using the drill. Once the rail is secure, you can install the insert. Your boat is now ready for another season of close-quarter encounters.

Since my Duffield has minimal flare, any encounters with another structure will not only be evident on the rubrail, but also on the hull. Everyone will know that I have rubbed something the wrong way; hopefully, it wasn’t my wife.

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