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Obsidian Surge Water Rower Review (Sunny SF-RW5713)

Today, we’re reviewing the Obsidian Surge water rowing machine, model SF-RW5713.

I’ve had a chance to try the rowing machine twice now, so I can say from experience how it compares to other options in the same price range.

Obsidian surge water rowing machine indoors
Not a bad-looking machine!

I’ve heard a good amount of feedback from owners, so I have a good idea of how it holds up over the long term.

Overall, the Sunny Health & Fitness Obsidian Surge water rower is a good affordable alternative to the expensive WaterRower models. It provides the same rowing experience and full-body workout without the fancy wooden frame and S4 monitor (the two main benefits of WaterRower brand models).

As for durability and sturdiness, it’s a solid rowing machine, but nowhere near that of WaterRowers. This is obvious when you compare the difference in weight capacity, with the Obsidian Surge capacity being ¼ that of a solid wood water rowing machine.

The simple monitor is only a downside if you want to race online with others or plan to get deeper into the hobby of indoor rowing at some point. An air rowing machine would be better suited for the sport since it’s the kind you’ll use at rowing and CrossFit studios.

For a good budget water rowing machine, you can’t do better than the Obsidian Surge 500. I’ve reviewed a handful at this point, and this one is the best for the money hands down.

If you like what you see, I recommend getting it at a major retailer. For the lowest price, choose a place that offers free shipping, which is typical of big retailers.

Resistance Type

The Sunny Health & Fitness SF-RW5713 is a water-resistance rowing machine. The resistance comes from the water instead of air or magnets, which offers a few benefits.

Unlimited Resistance

Water resistance operates by pulling the handle and spinning the paddles (hydro blades) suspended in the tank of water.

As you pull the handle, the paddles must “move” the water in front of them, thus providing resistance.

The faster you row, the faster the paddles spin, creating what’s called “viscous” resistance. So the faster you row, the more resistance you create!

We call this “variable” resistance because the amount of resistance depends on how fast you row. So, resistance goes up with increasing speed and thus is unlimited in that sense–unlike most Sunny Health machines that are limited by the magnet size, etc.

Air rowing machines operate the same way. You can see how air and water-resistance rowers compare to each other by reading my article here.

“Adjustable” resistance rowing machines exist, too, such as those with magnets and hydraulic pistons, which you can learn more about here.

There are 3 stainless-steel “Hydro Blades” (special fan blades) suspended in the water tank to provide dynamic resistance that feels like you are rowing on water!

Resistance Mechanism on Sunny Health Fitness Obsidian Surge Water Rowing machine

One major benefit of choosing a water rowing machine is that the noise is much lower than with an air rower. People enjoy being able to row while watching TV or allowing other family members to rest.

Most find the water sound to be meditative and use it as a way to relax!

How to Increase Intensity

Like with any water rowing machine, resistance operates using the “Rule of Cubes”.

This rule states:

“The resistance in rowing is due to the drag of the water moving over the hull of the boat. By the laws of hydrodynamics, this resistance/drag varies to the cube of the velocity/speed. The rule of cubes, therefore, dictates that a doubling of the speed of the boat will require an eight-fold increase in resistance.” –WaterRower

This means to feel more resistance, just row faster!

You can further increase the resistance by adding or subtracting water from the tank. The tank holds up to 3 gallons. Adding water makes the rowing stroke feel heavier and a full tank feels like rowing a boat by with people inside.

To change the water level, you can use the siphon and funnel that come with the rowing machine.

This does take a few minutes to perform but it is the same method used on the much more expensive WaterRower rowing machines.

Monitor/Control Panel

Close-up view of monitor on Sunny Health Fitness Obsidian Surge 500 Water Rowing Machine

The Obsidian Surge 500 Water Rowing Machine comes with the brand’s R2 Fitness Meter that lets you design your own personalized workout or choose from various pre-programmed features.

This digital monitor is designed to accurately track all essential workout metrics such as:

  • Total Time
  • 500m Split Time
  • Strokes per Minute (SPM)
  • Total Strokes
  • Distance
  • Calories
  • Heart Rate
  • Ambient Temperature (Room Temp)

So, the monitor tracks the essential workout metrics which is more than enough data to get a great workout! Plus, it’s very well organized in easy-to-read sections.

Sunny Health Fitness Surge Water Rower Monitor

The monitor will turn on by pressing any button and will turn off after 4 minutes of inactivity. When inactive, the monitor will display the current time.

2AA batteries are included to get you set up and rowing fast!

Monitor Features

The Sunny Health & Fitness SF-RW5713 monitor has a few features on top of the data tracking.

The monitor also has a few options to select from when starting. You can just begin rowing and have the metrics start counting. You can also pre-select a value such as Time or Distance and have the monitor count down.

While you can’t race with others online, there is a “Race” feature where you can select the pace of an “on-screen” digital boat and race it to the finish!

Users can purchase a compatible heart rate monitor separately and have their heart rate displayed on the monitor as they row. Compatible with ANT+ heart rate technology or any 5.3 kHz HR chest strap transmitter. Here is a list of the best-selling heart rate monitors.

You can then use the HRM to track your fitness level by selecting “Recovery” after a workout. The monitor will then calculate a score based on your heart rate and how fast you are able to recover.

Monitor Downsides

There were only a few downsides mentioned about the Obsidian Surge 500 monitor.

It’s not backlit and thus can be difficult to read in low-light settings.

The data tracking, while accurate, isn’t on par with the Concept2 PM5 or WaterRower S4 monitors. This is hardly a problem unless you plan to really get into the hobby in the near future.

Bottom Line

The SF-RW5713 water rowing machine comes with fitness technology designed to help users track their progress and achieve fitness goals.

It’s not as advanced as the high-end monitors of more expensive rowers (e.g, the S4 and PM5). Specifically, the data isn’t as accurate and you can’t race against others.

But the console displays the most important metrics like distance, time, calories burned, total strokes, and strokes per minute (SPM), and a few extras like ambient temperature and heart rate (monitor not included).

This allows users to monitor their performance and adjust their workouts accordingly to ensure long-term progress.

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Design and Build Quality

Sunny Health Fitness Surge 500 Build Quality

The Obsidian Surge 500 water rowing machine provides the same comfy and efficient workout experience of the wooden rowers, but in a sleek and modern design that’s lightweight and easy to move around.

It may not hold up to 1000 lbs, but it has a sturdy steel frame that can withstand regular use.

Light Weight Sturdy Steel Frame for Steady Rowing Experience

The steel frame is designed to be lightweight, yet sturdy and durable.

The rail is slim, but I felt quite stable when rowing. So, it’s stronger than it looks. Overall, it provides a stable platform for rowing.

Non-Slip Foot Pedals and Durable Nylon Velcro Straps

Aside from the frame, some of the smaller parts I found to be surprisingly good quality for the price. One thing I noticed was how secure my feet felt. The foot pedals are designed to be non-slip to provide a secure grip for your feet during your workout.

The pedals are adjustable, too, which allows you to find the perfect position for your feet. More on pivoting in the Comfort section.

This water rowing machine also comes with durable nylon Velcro straps, which can be adjusted to fit your feet securely.

Withstanding Water Corrosion

Importantly, any metal parts on a water rowing machine should resist corrosion.

Sunny Health & Fitness SF-RW5713 rowing machine uses a special coating designed to resist water corrosion.

Overall, the rowing machine is made of high-quality materials for a machine in this price range.

Check it out in action below:

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Sunny Health Fitness SF-RW5713 Comfort

Comfort is important since rowing is one of the few types of cardio that involves sitting for longer periods.

Rowing provides a full-body workout not matched by conventional cardio exercises–hitting almost 90% of your body’s muscular system at once, a higher calorie expenditure, etc. But it does involve more points of contact–namely, your butt, hands, and fingers. So, choosing a machine with a good design is important

The Obsidian SF-RW5713 has a molded, padded seat that I found to be reasonably comfortable. For long, hard rowing sessions you might still want to consider a rowing machine seat cushion.

The seat is large enough for any user at 10.0″ x 12.5″.

At 17.0″ off the floor, I found it VERY easy to get on and off. From what I’ve read, others seem to feel the same. The taller-than-average seat height helps prevent people from putting extra stress on their knees and back when getting on and off the rowing machine.

The seat sits on 3 sets of rollers and bearings for an extra smooth, quiet rowing stroke. Along with the water resistance (which is quieter than air), you’ll have no problem hearing the TV when rowing.

The non-slip foot pedals are great, but the pivoting part gets mixed feedback. They don’t pivot as you row, which can be bothersome since you have to stop to adjust your feet.

The pivoting is supposed to help with ankle mobility to ensure “optimal rowing mechanics”. While I’ve heard a complaint or two in this department, it shouldn’t be an issue since nearly every other rowing machine (including the most expensive) use fixed footplates.

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Portability and Storage

Sunny Health Fitness Surge 500 Water Rowing Machine Storage

Upright storage of Sunny Health Fitness Water Rowing Machine

The Obsidian Surge 500 is long at 80 inches, but it easily folds which reduces the length by more than half. Stored upright, it’s only about 33-1/2″ long.

When stored the Obsidian Surge 500 measures: 33.46″L x 22.05″W x 78.74″H

It has transportation wheels making it portable and easy to store.

To store upright, simply lift from the rear and roll the rowing machine forward on the high-density rubber wheels that prevent making any marks on your floor.

Then lift the rower vertically and move to your desired location. It’s best stored against a wall or in the corner of a room.

This water rowing machine rests on a front “end-cap” that is designed to hold the rower upright. There is no need to empty any water from the tank and it doesn’t feel heavy at all!

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Sunny Health Fitness Surge 500 Water Rowing Machine Capacity

The Obsidian has a weight capacity of 250 lbs, which is a bit below the average of 300 lbs–and a far cry from the wooden models that hold up to 1000 lbs!

It has a slide rail length of 42 inches and a slide rail inseam of 38 inches, which accommodates a max user height of around 6’4″ tall, on average.

As always, the max height depends on leg length. If you are over 6’4″, I would recommend measuring your inseam length and contacting the manufacturer to double-check.

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  • Assembled Dimensions: 
    • 78.74″ x 22.05″ x 33.46″ (L x W x H)
  • Stored Dimensions:
    • 33.46″ x 22.05″ x 78.74″ (L x W x H)
  • Assembled Weight
    • 81.6 lbs.
  • Shipping Dimensions:
    • 42.74″ x 22.4″ x 20.5″ (L x W x H)
  • Shipping Weight: 
    • 95.5 lbs.

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Pros and Cons


  • Smooth, quiet water resistance
  • Adjustable water level provides additional tension adjustment
  • Multi-function monitor that tracks the most important data
  • Convenient transport wheels and foldable design
  • Easy upright storage to save space
  • 17.0″ seat height for getting on and off easily
  • Easy assembly


  • No backlight on monitor
  • Must use siphon to add or subtract water
  • Average warranty

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  • Frame: 3-Years
  • Parts & Components: 90-Days
  • Model #: SF-RW5713

The 3-year frame and 90-day parts warranty are pretty standard with Sunny Health & Fitness equipment. They are pretty good about getting customers spare parts and luckily Amazon will step in if they try to make customers pay for items under warranty.

I do wish the parts warranty was a bit longer than 90 days but this is what they offer for all their lower-priced rowing machines.

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Sunny Health & Fitness Obsidian Surge 500 Review: Conclusion

The Obsidian SF-RW5713 is one of the best budget rowers in the water-resistance category. You’ll get the same great full body workout as you would with a luxury water rowing machine at less than half the price.

For a higher-quality water rowing machine and a better monitor, maybe check out the WaterRower A1 water rowing machine.

The A1 is named for having an A1 monitor which isn’t quite as advanced as the S4, making the model a bit less expensive. To find my reviews on these just visit my comparison table here and sort by “water” resistance.

As you may have seen when doing your research, the Concept2 Model D is often recommended as the #1 bestselling rowing machine on the market. It is the model I own and use every day, but it is more expensive. You can check it out here if you are interested.

I hope you enjoyed my Sunny Health & Fitness SF-RW5713 Obsidian Surge review! Please leave any questions or comment below!

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    1. Hi Bill,

      Regular tap water will be fine. Each rower will come with purification tablets and instructions. These will keep the water from becoming moldy.

      I’m sure you can find more if you run out at Walmart, Target, etc.

  1. Hi Edwin

    Purchased the Obsidian water rower.
    Straight forward assembley.

    I agree with others about the accuracy, on the Concept 2 I have 2;45-3-10 500 meter times.

    This one shows over 5 min. Need to try the Concept again to get my sr and total strokes.

    The siphon that comes with the rower is useless. I wish thsy had include a chart showing how much water for each level. # gal brought it to almost level 4, too much resistance.

    Just an fyi, the sticker on my unit now shows 300# capacity

    1. Hi Bill,

      Thank you for all the great feedback! We would love to hear how everything is going in a few months!

  2. Hey thanks for the review! I workout at a rowing club but for the money I’d be better getting one at home. I’ve only used WaterRower club A1 or concepts. I prefer Waterrowers.

    So my question is, any workaround with the inaccuracy or splits? I use them quite a bit with my workouts.

    Also, reading online and maybe I’m reading this WaterRower claims they create resistance by creating drag in the cylinder. They’re just saying by moving water which would be the same thing as this Sunny rower right or do WaterRowers use a separate flywheel to create drag resistance? Or let me ask it this way lol, I’m a 6’4” 235pd guy that has low splits, will this have enough resistance for me to get enough of a workout similar to WaterRowers?

    Thanks in advance you made search for these very simple easy!!

    1. Hey Josh,

      Unfortunately, there really isn’t a workaround for the inaccurate monitor. The best you can do is test yourself on a Concept2 then try to re-test under the same conditions on another rower and compare the results.

      As far as resistance, the WaterRower just uses paddles suspended in a tank of water to create resistance. As long as the surface area of the paddles and the amount of water is the same, then the resistance should be similar. I would say the Obsidian would have similar resistance to the A1 but could possibly lag a bit in quality, which makes sense due to the lower price.

  3. Thanks for the informative review! After reading many of your reviews, i I purchased the Sunny air/magnetic rower last night on amazon. Woke up this morning and this Sunny water rower is on sale for only about $20 more ($280 for air/magnetic and this is $299 on amazon). I’m a runner training for Boston and am currently injured, so I’m purely looking for a good workout and the most bang for my buck. Having it feel like rowing on water doesn’t matter at all to me. I don’t love the idea of having to mess around with emptying the water tank, etc. with this model. Is it significantly superior to the air/magnetic rower? It seems like the monitor is definitely superior? Which would you recommend?? Thanks so much!

    1. Hi Kelley,

      I would choose the SF-RW5713 if they are the same price. This model will allow a more complete rowing stroke without any forward limitations and it does have a better monitor.

      You can read my articles on the different resistance types to see if having a water rower is something you would rather have over air/magnetic resistance.

      Hope this helps!

    1. I would contact the Sunny Health & Fitness customer support. They will help resolve the issue or send you any replacement parts.

  4. I’m heavily debating between the Obsidian Surge and Concept 2 rower. I mostly workout in the early AM when the rest of the family is asleep, so noise is a huge concern. I understand the Concept 2 is the head of the class (at nearly double the cost of the obsidian), but will it be too loud? How much louder is the Concept 2 than the Obsidian Surge? Thank you!

    1. Hi Brett,

      It’s tough to say because everyone has their own opinion as to what is considered loud. I created a post about the Concept2 noise level here.

      I would say the Obsidian will be considerably quieter than the Concept2. However, if the room you are using the C2 in is far away from everyone, then they won’t be able to hear it.

  5. I’m stuck between the Obsidian and the Xterra ERG600W. If they were the same price, I’d probably go with the Xterra although The Obsidian is on sale for about $329, compared to $459 for the Xtrerra. What do you suggest?

    1. Hi Joshua,

      I agree, I would go with the Xterra if they were the same price but that is a great deal for the Obsidian Surge.

      I think I would pull the trigger and get the Obsidian Surge at that price. It’s a great rowing machine and it’s hard to find a good quality water rower for that price!

      I’d love to hear what you end up deciding on!

  6. Hi Edwin,

    On the Sunny Health Obsidian 5713 model, you mention 3 stainless steel blades in the tank? On their website it says 16 blades(no mention of what they are, they look like orange plastic) maybe the stainless are there and not viewable because of the orange cover inside the water tub?

    I’m deciding between this model and the Exterra ERG600W any idea how many blades in the Exterra 600W? I can’t find any info at all on that model or any like it. SunnyHealth is the only one that mentions the # of blades on their water rowers. I feel that may lend to the resistance as much as the water does, make sense? Or am I way off?
    Another question about Obsidian- do you know if there are any built in programs on the monitors? Exterra ad states they have 5 built in programs.

    Leaning towards Exterra because of the adjustable foot place holders(although you mentioned there were some issues with those). I have small feet– the Obsidian 5713 does not have adjustable foot plate and the foot place holder looks large/oval in shape , my concern would be my feet not staying in place or slipping out.

    I guess I have much to consider- any additional info you can add would be appreciated


    1. Hi Elizabeth – thanks for dropping a comment! I’ll answer your questions in number format below:

      1) It looks like Sunny Health & Fitness may have upgraded their “blades” and has a new design. If you look at the photos on Amazon you will see a uniquely designed system inside the tank that has 16 smaller “paddles”. I’m pretty sure the Xterra Erg600w has 3 large paddles. It’s tough to say which provides more resistance strength and it would depend on the amount of water and surface area of the paddles. I’d assume they are fairly similar.

      2) I believe the monitors are also similar. The 5 programs mentioned on the Xterra are programs like “time countdown” and “stroke countdown” so I’m not sure how much weight I would put on these “built-in programs”. They are nice to haves but I believe both monitors can perform these functions. If you want a full breakdown of the monitor functions I would visit the manufacturer website and read the manuals.

      Both rowers are fairly similar so it is a hard choice! I think both are great options and you will be happy with either option!

  7. I love the this machine for at home full body workout. Downside is I have small feat and it is hard to keep my feet strapped in when rowing. Second, my monitor recently stopped working and yes I changed out the batteries. It will not come back up and I don’t know where I can get a replacement.

    1. Hi Carol – thank you for the feedback! The best place to start would be contacting Sunny Health & Fitness customer service.

  8. I bought the Obsidian Surge during the beginning of the current pandemic as gyms were closed. Friends have the same model and highly recommended it, but warned me that their monitor began to malfunction and then stop working after some time. Mine (now 6mo later) has died. Where can I purchase a replacement for the monitor? I can’t seem to find a site online selling parts for the Sunny Fitness machines.

  9. Bought the Obsidian Surge in March when gyms closed. After about 7mo the monitor stopped calculating distance & strokes. I just received a replacement monitor on Christmas Eve, hooked it up, & put fresh batteries in. This monitor isn’t calculating them either. Everything is connected correctly. Any ideas on how to troubleshoot this issue?

    1. Hi D – it sounds like an issue with the sensor which is located somewhere on the seat rail. This would be sensing each stroke and calculating strokes and distance.

  10. Thanks for the information on the obsidian, I’ve been going back and forth between it and the snode water rowing machine. The two differences I see currently is obsidian slightly heavier which is good, the snode has a Bluetooth monitor which I’m not sure I’ll actually use. If you have information on both which do you think would be better for a beginner?

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