Cleaning a Hull in Water You Would Not Swim In

By Tomas Iglesias, Yacht service diver, South Florida. Reviewed by Amanda McCallister, editor.

Hull & Bottom Cleaning | Marine Salvage & Recovery On a Tuesday morning in August, the water around Pier 66 was 87 degrees and the color of weak tea. The client, an 85-foot Azimut with a green beard hangers on the props, watched me pull on my wetsuit. He said, 'I wouldn't put my dog in that water.' I told him, 'That's why they pay me, sir.' He laughed, but it wasn't a joke. For fifteen seasons I've cleaned hulls and running gear in Fort Lauderdale's intracoastal, the New River, and the turning basins off Port Everglades. The water you see on the postcards, that clear Bahamian blue, is out east. Here in the 'Venice of America,' the water is a mix of Everglades swamp runoff, tidal salt, two-stroke exhaust, and whatever a hundred thousand boaters have leaked, dumped, or flushed. Visibility is usually under a foot. On a bad day, it's zero. You don't look for the hull. You feel for it.

The Water You Work In

The intracoastal isn't just dirty; it's alive. In the hours after a heavy rain, the freshwater pushes in and the visibility goes to about a hand's width. The bottom turns to a black muck that grabs your fins. The surface shimmers with diesel rainbow. You drop over the side and the world goes dark. That's a normal Thursday. On Memorial Day weekend, the boat traffic is relentless and every wake shoves you against the hull. You hear the big diesels before you see them. A 60-foot Viking idles past with a wash that threatens to tear your mask off. You stay close to the barnacle line, breathe slow, and wait for the slap of the water against the stern to pass. The locals know this water is not for swimming. But we're not swimming. We're working. There's a difference, and it's mostly one of respect. The water doesn't care if it gets in your ears. It doesn't care if you're hungover. It's just there, and the job needs doing.

Gear You Hope You Never Need

My rig is simple: a 3mm wetsuit, heavy latex gloves, a bracket-mount dive light that sees through coffee, a steel scraper on a lanyard, and a set of brushes wrapped in Scotch-Brite scored with a knife. A back-up knife is strapped to my calf. You learn early that nothing is as strong as a monofilament fishing line wrapping itself around your tank valve. The wetsuit doesn't keep you warm; it keeps the stinging critters off. You also wear a full-face mask with a wired communications headset so the tender on deck can pull you up if something goes wrong. The comms crackle with messages like 'There's a USCG inspection coming by' or 'The owner wants to know if the shaft zinc is still there.' You learn to work blind and trust the setup. I've been diving these waters for fifteen years and the worst I've had is a rusty hook in my glove and a jellyfish sting on the neck. But you don't take chances. The person who says they never cut themselves in this water is lying. You clean the cut with peroxide after you're out, and you keep a tetanus shot current.

Cleaning a Hull Without Eyes

The first time you drop into a zero-visibility slip, your brain fights you. You reach for the hull and it's not where you think. It's closer. You bump into it with your tank. Then you center yourself and start feeling down the panels. Fouling grows in a pattern. The waterline gets a hard band of barnacles and algae. The bottom below the waterline is a mix of slime and tubeworms. On a sailing boat, the roughness slows you down. On motor yachts, the first thing to suffer is the propeller. For the hull, I hold the scraper flat and pull in overlapping strokes. You can feel when the blade bites under a barnacle cluster. You learn the texture: the gritty crunch of dead barnacles, the slimy give of algae, the hard plastic feel of epoxy that needs no scraping. On the running gear, the prop is the big job. I wedge myself between the propeller and the rudder and work by feel, making sure each blade has the same finish. The worst is when the zincs are gone entirely and the shaft has started to corrode. You feel the pitting under your glove, but you can't see how bad it is. You call the captain on comms and tell him he needs to haul the boat. Some owners hear that as a sales pitch. It's not. You're just tired of running your fingers over someone else's electrical problems.

The Hidden Wrecks and the Gators

Every diver in Fort Lauderdale has a story. Mine is the day my hand closed around a sharp edge just off the 17th Street Causeway bridge. Turned out to be a half-buried storm grate from a 1930s roadbed. You don't know what's down there: old anchors, bicycles, a shopping cart, the occasional sunken Jon boat that some kid ran aground. But the most unnerving are the gators. They float down from the Everglades and end up in the canals. They won't go for a kneeling diver, but when you surface and see a pair of eyes ten feet away, you do the crawl-on-your-tank thing and keep a hand on your knife. Not that you'd ever use it on a gator. You'd just rather have it. Then there are the creatures that leave marks on the hull. Sea lice bites during winter dry season. Spiny oysters that slice a glove. A green moray eel has a habit of hanging out near the exhaust risers. You learn to tap ahead before reaching into a void. It doesn't make the water swim-worthy. It just makes you quick.

What a Clean Hull Actually Costs (and Saves)

I'm not going to quote an exact number, because it depends on the length of the boat, the amount of growth, and how long it's been sitting. A typical 50-foot motor yacht with a heavy fouling will run anywhere from $300 to $800 for a full bottom and running gear, depending on access and whether your haul-out fee is included. Monthly maintenance is cheaper, usually a quick swim and scrub for a few hundred. But the real money is in the savings. A clean hull means the boat burns less fuel, hits the same speed at lower RPMs, and doesn't strain the transmission. On a pair of big diesels, that's not nickels. It's hundreds of dollars per season in fuel. Plus you avoid the dreaded prop burn that happens when the fouling gets so thick it starts eroding the metal. I tell clients: if you don't want to swim in the water, that's exactly why you should hire someone who will. I'm the guy. You don't have to like the water. You just have to like owning a boat that runs right.

Frequently Asked Questions

Is it really safe to dive in that water? Safe is a relative word. We wear full wetsuits and gloves, use a full-face mask, and have a tender on standby. The biggest risks aren't bacteria you can see; they're cuts that get infected and boat traffic. You manage the first with first aid and the second with a float flag and a careful look on the surface. Do you ever get sick from the water? In fifteen years I've had the occasional ear infection, but I've been lucky. The standard practice is to rinse with fresh water immediately after the dive, clean any cuts with antiseptic, and keep your vaccinations current. I've seen worse cases of swimmers' ear from people sitting in a hot tub. Could I do this myself with a kayak and a mask? You could, but you wouldn't enjoy it. Visibility is terrible, the current is often strong, and you need to know what you're feeling for. Plus, if you scratch a bottom through the antifouling, you've created a bare spot that will foul faster. A pro knows how to scrape without hurting the paint.