Rowing Machine NerdSunny Obsidian Surge Review
Water rower · ~$400
Sunny Obsidian Surge
A budget water rower offering smooth dynamic resistance and upright storage, held back by a basic console and short parts warranty.
The Sunny Obsidian Surge (model SF-RW5713, with a Smart SF-RW5713SMART variant) is Sunny Health & Fitness's bid to bring water-resistance rowing into the budget tier. Where most water rowers carry premium price tags, the Obsidian Surge slots in under roughly $460, pairing a 16-blade water flywheel with an elevated seat and an upright storage design aimed squarely at home users with limited floor space.
It is best understood as an affordable on-ramp to the water-rowing experience rather than a performance or commercial machine. Buyers drawn to the smooth, swooshing feel and the dynamic resistance of a water tank, but who do not want to spend on higher-end brands, are the natural audience. Those seeking precise data, long-term durability, or competition-grade consistency should temper expectations accordingly.
Specifications at a glance
| Resistance type | Water (16-blade flywheel, dynamic resistance) |
|---|---|
| Monitor | R2 Fitness Meter (LCD) |
| Metrics shown | Total time, 500m time, SPM, total strokes, calories, heart rate, ambient temperature |
| App / connectivity | SunnyFit App; 5.3 KHz heart-rate strap compatible (Smart model SF-RW5713SMART) |
| Assembled dimensions | 78.9" L x 22.3" W x 32.67" H |
| Machine weight | 91.9 lb |
| Max user weight | 300 lb |
| Storage | Stores upright; transport wheels |
| Warranty | 3-year frame, 180-day parts |
Pros
- Smooth, naturally dynamic water resistance that scales with stroke effort
- Stores upright with a manageable footprint for a water rower
- Elevated 17-inch seat makes getting on and off easier
- Affordable entry point into water rowing, typically under $460
- Smart model adds SunnyFit app workouts and Bluetooth heart-rate support
Cons
- Water tank needs periodic maintenance and has reports of cracking or leaking over time
- 180-day parts warranty is short next to the frame coverage
- Basic R2 console lacks the depth and accuracy of premium consoles
- Build quality is mid-tier rather than commercial-grade
Best for: Budget-minded home users who want the smooth feel and ambiance of a water rower without paying premium-brand prices.
The water feel is the real draw, and it largely delivers
This is the part of the Obsidian Surge that punches above its price. The sealed tank with its suspended hydro blades produces genuinely dynamic resistance: pull harder and the water pushes back harder, with no resistance dial to fiddle with. Owners consistently describe the stroke as smooth and fluid, and the soft whooshing of the paddles moving through the tank is the calming, on-the-water soundtrack that draws people to water rowers in the first place. It is noticeably quieter than a chain-driven air rower, which matters if you row early mornings or in an apartment.
The honest caveat is that self-regulating resistance has a ceiling. Because the only way to get more load is to row faster and more aggressively, very strong or competitive rowers can max out what the tank gives back. For general fitness, steady-state cardio, and most beginners to intermediates, that ceiling is a non-issue. But if you are training for power or want repeatable, precisely calibrated workloads, the lack of a damper or adjustable resistance is a real limitation rather than a quirk.
The R2 console does the basics and not much more
The R2 monitor covers the essentials: time, stroke count, calories, distance, and a count of strokes per minute, plus a few preset programs and heart-rate compatibility. For casual tracking that is adequate, and most budget buyers will not feel cheated on day one.
Where it falls short is depth and trust. Reviewers note the data is reasonable but not in the same league as a Concept2 PM5 or a WaterRower S4 for accuracy, and the calorie and distance figures are best treated as motivational rather than precise. More concerning are owner reports of the display zeroing itself out mid-session, which is maddening when you are trying to track intervals. If you live by your numbers or want to benchmark against others, the console is the weakest link here, and no firmware will fix that on the base model.
Build quality is the thing to go in with eyes open about
The steel frame feels sturdy enough and the 17-inch elevated seat is a genuinely thoughtful touch that makes getting on and off easier, especially for older users or anyone with knee issues. Upright storage with a manageable footprint is another real win for a water rower, a category that usually demands a lot of floor space.
But this is a mid-tier machine, not a commercial-grade one, and the recurring complaints cluster in predictable places. The most serious is the water tank: multiple owners report cracking or leaking over time, often where the tank bolts to the frame and the vibration of rowing works the joint loose, in some cases after about a year of regular use. Others mention roller plastic wearing and getting noisy, and the assembly is fiddly enough that non-DIY types may want a second pair of hands. The 300-pound weight capacity is also lower than many rivals. None of this makes the rower a bad buy at the price, but it does mean you should expect to maintain it and not treat it as buy-it-for-life equipment.
Maintenance is part of the deal with this one
Like all water rowers, the Obsidian Surge asks for upkeep that an air or magnetic rower does not. Sunny includes anti-algae tablets, a funnel, and a siphon pump; the routine is dropping a purification tablet roughly every six months and changing the water periodically, or sooner if the tank turns cloudy. That is a few minutes of housekeeping, not a chore, and many owners enjoy the ritual.
The bigger maintenance reality is the tank durability noted above. Because reports of leaks and cracking are not isolated, it is worth registering the product promptly, keeping the rower on a level surface, and not over-tightening or ignoring the tank-to-frame hardware. The short 180-day parts warranty makes this more pressing: the three-year frame coverage is fair for the money, but the part most likely to fail, the tank, is the part you are least protected on after the first six months.
How it stacks up against the obvious alternatives
At around $400 the Obsidian Surge is roughly half the price of the machines it gets compared to, and that framing matters. The natural rival in spirit is the WaterRower Natural, which starts near $1,200 and buys you a beautiful hardwood frame, a more trustworthy S4 monitor, and the kind of build that holds up for years. The Obsidian gives you most of the water feel for a third of the price, but you can tell where the savings came from in the plastics, the console, and the warranty.
The harder comparison is the Concept2 RowErg at around $990. It is not a water rower, so it trades the soothing whoosh for a louder fan, but on every metric that affects long-term ownership it wins: the PM5 monitor is the gold standard for accurate, comparable data, parts are cheap and DIY-replaceable, resistance has no practical ceiling, and resale value is famously strong. If your budget can stretch and you care about training data or longevity, the Concept2 is the smarter long-term buy and most serious rowers should save up for it. The Obsidian Surge wins on exactly two axes: upfront price and the water experience. That is a legitimate niche, just a narrow one.
The smart model is a modest upgrade, not a different machine
The Smart Obsidian Surge adds Bluetooth and access to the SunnyFit app, which brings guided and scenic workouts and easier heart-rate pairing. If you respond to follow-along classes, that can be the nudge that keeps you rowing, and the app content is a reasonable freemium layer rather than a locked ecosystem you are forced into.
Set expectations accordingly, though. The underlying hardware, the same tank, frame, and seat, is unchanged, so all the durability and resistance-ceiling caveats carry straight over. The smart version is worth the small premium only if you genuinely want app-led sessions; if you just want to row to your own numbers, the extra spend buys you little, and you would arguably be better off putting that money toward a sturdier machine.
Our take
Buy the Obsidian Surge if you specifically want the water-rowing experience, the smooth dynamic pull and the calming sound, on a tight budget, and you are realistic that this is an entry-level machine you will maintain rather than a lifetime investment. It is a strong fit for beginners and casual-to-moderate exercisers, for people short on space who value the upright storage, and for anyone who finds an air rower's noise and engine-block monitor off-putting. The elevated seat also makes it friendlier than most for older users.
Skip it if you train seriously, live by your performance data, or want something that will shrug off years of hard use without fuss. In those cases the short parts warranty, the basic console, and the documented tank failures should steer you toward a Concept2 RowErg, or to the WaterRower Natural if the water feel and a premium build are non-negotiable. At 3.3 out of 5 this is a competent budget pick that knows its lane; it earns its place on price and feel, and loses ground on console depth and long-term durability.
Our verdict
The Sunny Obsidian Surge is the budget on-ramp to water rowing, and judged on that brief it largely succeeds. You get the smooth, self-scaling pull and the soothing whoosh that people pay three times as much for, plus a thoughtfully elevated seat and upright storage, for around $400. What you do not get is depth or durability: the R2 console is basic and occasionally drops its readout, the build is mid-tier, and the recurring reports of the water tank cracking or leaking after a year or so are the real shadow over an otherwise likeable machine, made worse by a stingy 180-day parts warranty.
Recommend it to beginners and casual exercisers who want the water feel without the water-rower price, who value quiet operation and space-saving storage, and who accept this as an entry-level machine to maintain rather than a forever purchase. Tell anyone who trains seriously, lives by their data, or wants buy-it-once durability to spend up on a Concept2 RowErg, or on a WaterRower Natural if the look and feel matter most. At 3.3 out of 5 it is a fair-value pick that knows exactly what it is and does not pretend to be more.
Frequently asked questions
- Is the Sunny Obsidian Surge quiet enough for an apartment?
- Yes, for the most part. The dominant sound is the gentle whoosh of water moving through the tank, which is meaningfully quieter than a chain or fan air rower and is one of the machine's genuine selling points. The main exception is owner reports of roller plastic wearing over time and becoming noisier, so keep the seat rail clean and watch the rollers as the machine ages.
- How much maintenance does the water tank actually need?
- Routine upkeep is light: drop in one of the included anti-algae purification tablets about every six months and change the water periodically, or sooner if it looks cloudy. A funnel and siphon pump are included. The bigger issue is durability rather than cleaning, since several owners report the tank cracking or leaking where it bolts to the frame over time, so keep it level and check the tank hardware periodically.
- Can I get a hard enough workout on it as I get fitter?
- For general fitness and steady cardio, yes. Resistance is self-regulating, so it scales up the harder and faster you pull. The limitation is that there is no damper or resistance dial, so strong or competitive rowers can eventually hit the ceiling of what the tank pushes back. If you want precise, repeatable, high-load training, this is the wrong tool.
- Is the warranty any good?
- It is mixed. The roughly three-year frame coverage is fair at this price, but parts are only covered for about 180 days. That short parts window is a real concern given that the component most likely to fail, the water tank, can develop leaks after the warranty lapses. Register the product promptly and inspect the tank-to-frame hardware as part of upkeep.
- Should I pay extra for the Smart version with the app?
- Only if you actually want guided, app-led workouts. The Smart model adds Bluetooth and the SunnyFit app with scenic and instructor-led sessions plus easier heart-rate pairing, but the frame, tank, seat, and resistance are identical to the standard model. If you prefer rowing to your own metrics, the upgrade buys you little.
References
- Premium Smart Obsidian Surge 500 m Water Rowing Machine (SF-RW5713SMART) - Sunny Health & Fitness
- Sunny Health and Fitness Obsidian Surge 500 Water Rowing Machine Review - Garage Gym Reviews
- Sunny SF-RW5713 Obsidian Surge 500 Rower Review - Rowing Machine Guide
Jordan Lockwood (BSc, CPT)
Certified personal trainer (CPT), sports-science graduate, and lifelong rower. Jordan writes and reviews every guide on Rowing Machine Nerd.