Hey everyone, thanks for stopping by the blog! If you’ve spent any time browsing crawler chassis lately (especially if you’re shopping around for reliable ground movement solutions), you’ve probably asked yourself this question at some point: can a crawler chassis even hold up underwater? Crawler Chassis
I get it—when most people think of crawler chassis, they picture heavy construction equipment plowing through mud on land, robots navigating dirt paths in a warehouse, or even toy tracks zooming across your backyard lawn. The idea of submerging those tracks in water, saltwater, or murky underwater muck sounds pretty wild, right? For years, our team here at the crawler chassis supply company got this exact question nonstop. A lot of folks wrote them off straight away, like water and rubber tracks or metal sprockets are just a terrible mix. But after working with dozens of clients over the last few years—from underwater drone builders to aquaculture maintenance crews to coastal search and rescue teams—we’ve learned this isn’t a straight yes or no answer. It’s way more nuanced than that.
First, let’s break down why people used to think crawler chassis can’t go underwater. Let’s start with the basics: crawler systems rely on a few key parts to work. There’s the track itself (usually rubber for small units, steel for heavy industrial stuff), the sprockets that turn the tracks, the rollers and idlers that keep the tracks tight, and the frame that holds all that together. On land, most of these parts use materials that work great in dirt, oil, dust, and rain—submersion is a whole different beast.
For steel parts, the big enemy is rust. If you take a standard steel sprocket or roller and dunk it in saltwater, which is way more corrosive than regular freshwater, it’s gonna start pitting within weeks, maybe even days. That’s a huge problem because a crawler only moves if those sprockets can grip the tracks, and if a roller seizes up from rust, the whole thing grinds to a halt. Then there’s rubber tracks. Most standard rubber is made for road or off-road use—some can handle light rain, but prolonged submersion? It breaks down. The rubber gets waterlogged, it loses its grip when it’s wet, and the oils used to keep it flexible leach out, making it crack and fall apart way faster.
Wait, but that’s the old standard stuff. Our clients don’t want a crawler that works for 10 minutes and dies. They need something that works for hours, days, even weeks underwater, no issues. So what do you change? Let’s talk about the material tweaks that make this possible, because that’s the game-changer here.
First up, the frame and structural parts. If you’re building an underwater crawler, you can’t use plain steel. We started testing 316 stainless steel a few years back, and let me tell you—this stuff is a game-changer. It’s not 100% rust-proof (nothing is, really) but it’s highly resistant to corrosion in saltwater, freshwater, and even that nasty, sulfur-rich muck you find at the bottom of lakes or bays. We also have a few clients who use coated aluminum frames, for lighter-duty underwater stuff like small inspection robots. Aluminum is way lighter than steel, but you have to get the right anodized coating—regular anodizing wears off fast under constant submersion. The hard-coat anodized we use? It sticks, doesn’t flake, and holds up for years.
Then there’s the track. Standard rubber is out, but we found two great alternatives that work way better. For lighter units (like the kind used for pipeline inspections in shallow water), we use marine-grade polyurethane tracks. Poly holds up way better in water than rubber—it doesn’t get waterlogged, it resists UV rays if you’re moving around near the surface, and it’s tough enough to handle small rocks or sediment on the underwater floor. For heavy-duty stuff—like crawlers used to pull sensors or dredge small debris from the bottom of a harbor—we use heavy-duty steel tracks, but they’re coated with a special anti-corrosive polymer. We tested those last year in a saltwater test tank for 6 months straight, and there was almost no sign of rust. The coating didn’t even peel.
Wait, what about all the moving parts inside? The bearings, the shafts, the sprockets—those are the most important bits that make a crawler work smoothly, right? Regular bearings would seize up instantly underwater. So we switched to sealed, grease-packed bearings that are rated for submersion. Not just “water-resistant”—these are “can sit at 100 feet underwater for 2 years without needing a regrease” rated. We also use food-grade, non-toxic grease for some of our aquaculture clients, because they don’t want any chemicals leaching into fish tanks or shellfish beds. That was a big request—one client does underwater shellfish population surveys, and they didn’t want their crawler harming the stuff it’s surveying.
Now, let’s get into real-world use cases, because that’s where the rubber meets the road (pun totally intended). A few years back, we hooked up a custom crawler chassis to an underwater ROV (remotely operated vehicle) for a coastal search and rescue team in Florida. They needed something that could move across the murky, mucky bottom of the Gulf of Mexico, where regular propeller-driven ROVs get stuck in the silt. The crawler chassis we built for them? It can go down 150 feet underwater, runs on lithium-ion batteries that are sealed so no water can get in, and it’s been working nonstop for almost 3 years now. They use it to search for lost fishing gear, boat parts, and even personal items like phones or wallets that people drop overboard. The team says it’s way more reliable than their old propeller ROVs—they haven’t had to replace a track or a bearing in that time.
Another client is an aquaculture farm in Norway. They have salmon pens that need to be cleaned every few weeks, and the algae and barnacles growing on the pen nets are a nightmare. Their old crawler (land-based, obviously) wouldn’t work when they had to wade into the shallow water around the pens, so they came to us for a submersion-rated chassis. We built them a small, lightweight unit with polyurethane tracks, aluminum frame, and sealed motors. It’s used in 10 feet of saltwater, moves along the pen nets, and sprays a mild, non-toxic solution to kill algae. They told us it cut their cleaning time in half, and they haven’t had to do any repairs on the chassis since we delivered it two years ago. That’s huge for them—time is money when you’re running a farm.
Wait, but it’s not all smooth sailing, right? There are still limitations, and I don’t want to sell anyone something that won’t work for their needs. First, depth. Most of our submersion-rated crawlers are rated up to about 300 feet. If you need something for deep sea—like 10,000 feet, where submersibles go—we don’t have that yet. The pressure at that depth is insane, and even our stainless steel parts can get crushed if they’re not reinforced for high pressure. That’s a whole different engineering problem, and we’re still working on it, but right now our stuff is for shallow to medium-depth underwater work.
Then there’s power. If you’re running a crawler underwater, you can’t plug it in easily—so it needs batteries. We use high-density lithium-ion batteries that are completely sealed, no vents, no exposed wires. But keep in mind, the deeper you go, the more pressure you put on the battery seals. We test every single unit we build at our workshop before it goes out, submerging it in a test tank for 72 hours straight to make sure no water gets in. But even with that, if someone’s using the crawler in super cold water (like near the Arctic, or glacial lakes), we have to adjust the battery type. Regular lithium-ion dies fast in freezing temps, so we use lithium-iron phosphate batteries that hold up in cold.
Another big thing: traction. Underwater, there’s less friction between the track and the ground than there is on land. Silt, clay, small rocks—those all make it hard for tracks to grip. That’s why we design our underwater tracks with a deeper tread pattern, similar to the treads on a heavy-duty construction track, but modified so they don’t trap as much sediment. We also do custom tread designs for clients who work in super mucky areas—one client in the Pacific Northwest works in muddy riverbeds, and we built them a track with open slots that let silt fall out instead of getting stuck, so they don’t slip all the time.
I think a lot of people also worry about maintenance, right? If you’re running something underwater, cleaning it after every use is a big job. But our crawlers are actually pretty low-maintenance. The sealed parts mean you don’t have to regrease bearings every month—you just rinse the whole chassis off with freshwater after use to get rid of salt or sediment, and that’s it. For heavy-duty units that work a lot, we recommend a once-a-year inspection to check the polymer coating on the steel parts, but that’s way less work than maintaining a standard underwater vehicle.
Wait, let’s address the elephant in the room: cost. Submersion-rated crawlers aren’t cheap. The materials—316 stainless, hard-anodized aluminum, sealed bearings, marine-grade tracks—are way more expensive than standard off-the-shelf parts. But when you compare it to the cost of replacing a whole underwater ROV every year, or losing days of work because your unit breaks down, it’s worth it. Our clients tell us that within 6 months of using our crawler, they’ve made back the extra cost in saved time and repairs.
We also get a lot of people asking about saltwater vs freshwater. Is one easier than the other? Freshwater is way less corrosive, so a crawler built for freshwater use will last longer than one built for saltwater. But we can customize any unit for either, or even for areas where you switch between both, like coastal areas that have both rivers and the ocean.
Let’s wrap this up with the big takeaway, because I know you’re here for a clear answer. Can a crawler chassis be used in underwater environments? Hell yeah, it can—if you build it right. It’s not a one-size-fits-all solution, and it’s not for super deep sea work, but for shallow to medium depths, for tasks like pipeline inspection, aquaculture maintenance, search and rescue, underwater construction, even scientific research, a properly built submersion-rated crawler chassis is way more reliable than a propeller-driven underwater vehicle. It can handle muck, rocks, uneven terrain that propellers get stuck in, and it’s easier to control for straight-line work or climbing gentle slopes underwater.
If you’re someone who’s been searching for a ground vehicle for underwater work, don’t write off crawler chassis just because your first thought was a standard construction track. Talk to us—we’ve worked with every kind of client, from small startups building underwater robots to large industrial companies with teams of engineers. We can walk you through what parts work for your specific needs, what depth you’re working at, what kind of water (fresh vs salt vs mucky river) you’re dealing with, and build a custom crawler chassis that fits exactly what you need. No generic stuff, no overpaying for parts you don’t need.
If you’re tired of ROVs getting stuck in the silt, or propellers breaking on every rock, or units seizing up after a few weeks of submersion, hit us up. We’re here to help you find the right solution, and we’ve got decades of experience building crawler chassis for every environment, including underwater. Don’t let anyone tell you crawlers can’t go underwater—we’re living proof they can, and they work really well when built right.
Thanks again for reading, and feel free to reach out for more info anytime.
Tracked Drill Rig Chassis References
- ISO 12944: Corrosion Protection of Steel Structures by Protective Paint Systems
- Society of Automotive Engineers (SAE) J1926: Sealed Bearings for Submersible Applications
- National Oceanic and Atmospheric Administration (NOAA): Coastal Underwater Vehicle Terrain Compatibility
Murphy Construction Machinery (Shandong) Co., Ltd.
Murphy Construction Machinery (Shandong) Co., Ltd. is one of the most professional crawler chassis manufacturers and suppliers in China, also supports customized service with low price. Please feel free to buy CE approved crawler chassis made in China here from our factory. For pricelist, contact us now.
Address: Room A3, Zone E, Yangqiao Industrial Park, Liuxing Street, High Tech Zone, Jining City, Shandong Province
E-mail: mefgcjx@126.com
WebSite: https://www.mefjx.com/
