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Toss the Sawzall!

So a guy walks into a boatyard and says, “Hey, I gotta have a bow thruster.” In a few days, an open-ended job begins, with the bill contingent upon the yard’s hourly rate, expertise, and the man-hours worked. When the guy returns he finds his boat starring in a veritable horror show. A couple of first-time thruster installers have blundered into a foam-cored transversal while cutting a hole in the wrong place with a Sawzall. The damage is serious, with whopping cost overruns in the offing.

True? Yes, unfortunately, but not an indictment of boatyards, which are typically staffed by competent workers. The point is to promote a phenomenon gaining popularity these days: expert crews that rove the nation in trucks and vans, installing electric and hydraulic thrusters on both new and older boats with specialized tools, locked-in pricing, and high levels of expertise and efficiency.

Why have them install your thruster? I got the answer from John Wurtz, vice president of Florida Bow Thruster, an outfit with six, two-man crews that travel Florida (and often other parts of the United States) doing roughly 400 thruster installs a year. Burt Mattke, a friend of mine who manages the boatyard at Lighthouse Marina in Panama City, Florida, steered me toward Wurtz as a reliable source of info, based on jobs he’s seen Wurtz’s crews do.

Here’s the drill: Once an owner’s signed a contract with Wurtz (which includes a firm price and a lifetime guarantee), a fiberglass technician and an electrician arrive at the boat, protect her interior with drop cloths, and then level her athwartships in her trailer or cradle in accordance with her waterline.

The next step’s crucial. After referring to the waterline, rubrail, stem, and other features, they drill two half-inch pilot holes on either side of the bow, creating an axis that centers and levels the thruster-tube cutouts. To obviate mistakes like stumbling into a transversal, they recheck their measurements, inside and out. They also ensure the cutouts are at least half of the tube’s diameter below the waterline and as far forward as possible.

The third step’s drama is significantly diminished by the specialized tools and standardized procedures used. Holding an electric drill powering a can-like hole saw with a six-foot-long drill bit sticking out (see drawings above), a guy bores two 17⁄8" guide holes through the pilot holes and then keeps right on going until the first thruster-tube cutout’s been partially excised. Next he switches to the opposite side of the bow and excises the second cutout entirely while using the bit and guide holes to maintain his lineup. Then he returns to the first side and finishes that cutout.

The last step’s easy. After any coring material around the cutouts has been removed and the area has been sealed with resin, the tube is glassed into place, faired into the hull exterior, and painted. Then finally, the thruster assembly (motor, drive leg, and propeller or propellers), electrical cables, and control system are installed.

The savvy way to go? You bet, especially when you consider the job I just described takes just 20 hours; costs a reasonable amount (an install on a 36-footer runs about $7,900); and virtually nixes chances of your boat starring in a horror show thanks to specialized tools, techniques, and expertise.

Florida Bow Thruster (866) 847-8783.


1.) Juice: A bad battery’s an electric thruster’s worst enemy. Make sure your’s battery is always fully charged.

2.) Corrosion Protection: Ocassionally check the small zinc on your thruster’s drive leg.

3.) Brush Up: Electric thruster motors need new brushes every few years.

4.) Fluid Check: Drain and check fluid in a hydraulic thruster periodically.

This article originally appeared in the August 2009 issue of Power & Motoryacht magazine.