Running Gear Service: What a Full Underwater Package Includes

By Tomas Iglesias, Yacht service diver, South Florida. Reviewed by Dana Whitcombe, technical reviewer.

Propeller Removal & Repair | Hull & Bottom Cleaning Six-thirty this morning, I'm in the water off a 70-foot Ocean Alexander, and the stink of dead barnacles is already in my nose. I'm down there to look at a shaft vibration, and the owner's already on the phone asking about haulout. I tell him to hold off until I get a look. A full running gear service package is not just a hull scrub. It's a systematic inspection and maintenance of everything that spins and steers your boat. I've done this 15 years in Fort Lauderdale, and most surprises are predictable if you check the right stuff. Here's what I mean by full package, and why you'll want it done before a season hits.

What a Full Running Gear Service Covers

When I work a boat, I'm looking at props first. I'll check blades for dings, bends, and that proper pitch and cup. I use my fingers and a thumbnail to feel for burrs. I'm also eyeballing the shafts for runout, though below 1,000 RPM you usually can't see it; that takes a dial indicator on the hard. Then cutlass bearings—that's the sleeve that supports the shaft exit. I'll try to wobble the shaft. If it moves more than a 1/16 of an inch at the strut, call it worn. You can't measure clearance exactly underwater without hauling, but you can feel it. Then rudders and posts, trim tabs, through-hulls, and the strut itself. I'm checking for cracks, loose fasteners, damaged anodes. I'll replace zinc anodes right there with a socket wrench and a bit of thread compound. I'll also clear the rope, line, plastic, and fishing wire off the running gear—that's the thing that causes most mid-season surprises.

The Tools of the Trade

My bag is not that big. Knife, scraper, several wrenches, a torque wrench, underwater epoxy, and a camera that shoots hi-res photos and video. I've got a set of SS shaft guards that I can fit from below, and a full set of anodes for common shaft sizes from 1 inch to 4-1/2. I like OEM anodes for the big boats—that's no place to cheap out. On the dive side, I'm working off a surface air supply, not a single tank. That gives me bottom time to do the job right. I use a comms box or a slate. And every time, I take video. The owner wants proof, and I want to show them what I saw before I touched anything.

When Routine Becomes Repair

There are jobs you can handle under water, and jobs you shouldn't. Polishing a prop with emery cloth takes care of some fouling and minor roughness. Replacing an anode or clearing a line—no problem. But a bent prop with a visible wobble, a cracked shaft, a split cutlass bearing, a leaking shaft seal—that's a haulout job. Once I found a shaft that had worn almost all the way through at the stuffing box. The owner was talking about a simple clean. Instead, I gave him a video of the corrosion and told him flat out: don't run that boat. Call it a lucky catch. If we'd only done the package, he'd have been stranded offshore. That's the part of my job that doesn't show in an ad. Sometimes running gear service is more about the diagnosis than the polishing.

Scheduling, Cost, and the Pricing Model

The price for a full underwater running gear service depends on the boat's size, condition, and the diver. Most shops quote a flat fee per foot, and that includes cleaning and inspection of running gear, plus a basic report. Reputable divers don't charge per part unless it's a custom deal. A typical package on a 50-foot boat—cleaning, anodes, inspection, and video report—runs in the low three figures per foot, with the anodes extra. But that's a ballpark, not a price list. It varies with the plant, the marina, and the season. More important is frequency. If you run a boat hard in South Florida, I'd say every 90 days for fouling control and anode check. Once a season for a full package is the bare minimum. You'll need more if you're in dirty water or near the inlet.

How to Get a Good Underwater Service

Ask the diver what's included. A full package should cover all under-hull appendages, not just the props. Make sure you're getting a photo or video report. If a diver says they can fix a shaft seal underwater, run, don't walk. The good ones tell you when it needs a haulout. Also, look for someone with commercial dive insurance and a track record. In Fort Lauderdale, there's no shortage of guys with a tank and a scraper. Ask for references, check they've worked on your brand of running gear—Volvo Penta, Yanmar, Zeus, whatever. And get the scope in writing, even if it's a one-page quote.

Frequently Asked Questions

How often do I really need running gear service? Honestly, depends on where you boat. In Fort Lauderdale, I recommend a quick look every 90 days to check anodes and clear fouling. A full running gear service—props, shafts, cutlass bearings, rudders, trim tabs—once a year at least. If you notice vibration or loss of speed, get it checked sooner. Can you replace a cutlass bearing underwater? Not usually. On some smaller boats, you can force out the old bearing and press in a new one with a special rig, but most of the time the shaft has to come out, which means haulout. I'll tell you honestly if it can be done underwater—I've done it twice, but it's rare and depends on the installation. Will a running gear service stop my shaft vibration? It can, if the cause is fouling, a strummed line, or a slightly bent prop that just needs cleaning and a light polish. If the vibration is from a deeply bent prop, a worn cutlass bearing, or a sprung shaft, then no. I'll tell you what will and won't fix it. What does a full underwater running gear service cost? Most divers quote a flat fee that tracks with boat length. On a 50-foot boat, you might pay anywhere from $200 to $500 for a full package with anodes, depending on condition and the shop. But I wouldn't shop by price alone—check the diver's experience and what exactly is included.