Underwater Propeller Removal: How Divers Pull a Prop Without a Haul-Out
By Tomas Iglesias, Yacht service diver, South Florida. Reviewed by Dana Whitcombe, technical reviewer.
Propeller Removal & Repair | Hull & Bottom Cleaning Last Thursday I pulled a 26-inch Veem five-blade off a 110-foot Hatteras without leaving the water. The owner had a slot at the yard in two weeks, but he had a trip Friday. So I went down with my gear and did the job in 45 minutes. We made it look easy because it is—once you know what you're doing. That's the whole pitch for underwater propeller removal. It saves you the cost of a haul-out, the time on the hard, and the hassle of pulling the boat out of a rental slip. In South Florida, most yards are booked up for weeks anyway. And a diver with the right tools can handle a stuck prop on the bottom just as well as a mechanic on dry land—better, in some cases, because I can see exactly what's happening on the shaft while it's still in the water.
Before You Grab a Puller, Look and Document
First thing I do is swim the prop and shaft. I take a GoPro along and shoot the whole thing before I touch anything. That gives the owner a clear before picture and me a reference if something goes wrong. Then I scrub the exposed shaft and the prop boss with a stainless steel brush to get the barnacles and corrosion off. I look for the cotter pin or tab washer on the prop nut. Most boats run a castle nut with a cotter pin, but some use a nylon insert lock nut. I always carry a handful of each size in my gear bag. I also check the prop itself. If it's beat up or bent, it's coming off easier than you'd think. If it's been on for years and the anode is shot, the taper might be seized. That's when you plan for extra time. But the prep is the same: get the nut free, clean the threads, and make sure you can get a puller on it.
The Pull: Hydraulic Pressure and a Little Patience
Once the nut is off, the prop still doesn't want to come. It's on a taper or splines, and it's been there for years. I use a hydraulic puller—call it a hydraulic gear puller. I carry an Enerpac P-38 hand pump and a small cylinder head with an adapter that grabs the back of the prop and pushes on the shaft. You tighten it down, give the shaft a few taps with a bronze maul, and pressure does the rest. If it's really stuck, I'll hit it with a small underwater torch. That's a last resort, and it takes practice to do without damaging the seal. In a bad current, you learn to wedge your body between the boat and the prop to stay put. I've had to hand the pump to a deckhand above and have them work it while I hold the puller centered. And yes, I've been the guy holding his breath for a long count while the prop finally pops. But it's not a race. You crack it a little, let the pressure sit, tap the shaft, and crack it again. That's the way. I once had a prop on a 60-foot sportfish that was so corroded the puller literally tore the center out of the prop. The owner thought I'd broken it. I showed him the before and after video and he calmed down. That kind of thing happens when zincs are neglected.
When the Prop Lets Go, Don't Lose It
The thing most people don't realize is the prop can come off with a bang and sink. So I've got a line around it before I even start. I rig a short sling around the hub and run the line to a boat hook or a deckhand. When it lets go, it'll drop maybe an inch before the sling catches it. Then I just float the prop up to a staging bag or hand it to a deckhand. I always check the shaft and keyway for wear and corrosion. If I see a groove or a crack, I tell the captain to get a surveyor or a shaft specialist. That's the kind of thing an underwater pass catches that a haul-out might miss—you can see the exact condition in situ, with the shaft in its natural alignment. And I take a close look at the cutlass bearing and the zincs while I'm right there. It's all part of the service.
What Comes Next: Cleaning and Reinstalling
Sometimes the job ends with the prop in my hand. But more often the owner wants me to swap props—put on a spare or a smaller one for speed. I'll clean the shaft taper and smear on a thin coat of Teflon grease or an anti-seize compound. I always use a new key and a new nut. Torque it to spec. I don't guess torque—I carry a torque wrench that's calibrated, and I know the standard for each shaft size. If the prop is going to the shop for a re-pitch or reconditioning, I'll tag it and hand it off. If my client wants me to store it, I'll bag it and keep it in my truck. Either way, the boat never leaves the water. And that's the point. For most boats under 150 feet, underwater prop removal is routine. It's the kind of job that used to be a haul-out only, but not anymore.
Frequently Asked Questions
How long does an underwater propeller removal typically take? Give or take 30 to 60 minutes once I'm in the water. A seized prop can stretch that to two hours. Add prep time on the dock and maybe 15 minutes for setup. Can a diver remove a propeller in poor visibility? Yes, but it's slower. I carry a strong dive light and work by feel as much as sight. In Fort Lauderdale, murky water is common in winter after a storm. Is underwater prop removal safe for the shaft seal and running gear? As long as the diver is careful. I use a bronze maul and never strike the shaft or prop brass directly. I also inspect the seal and cutlass bearing while I'm under there. What tools are needed for a standard removal? A wire brush, a puller kit, a torque wrench, a bronze maul, plus cutting tools if the prop is fused. I carry spares for every size.