Sunny Health & Fitness SF-RW5713 Obsidian Surge Review

Sunny Health & Fitness SF-RW5713 Obsidian SurgeI’m not sure of the exact “full” name, but I think it’s the Sunny Health & Fitness SF-RW5713 Obsidian Surge Water Rower.

I’ve seen it called all different names, so don’t mind all the variations in this review!

Whatever you want to call it, just know it’s an excellent budget water rower.

With strong, smooth resistance and great quality, the SF-RW5713 has quickly become a top seller.

Especially now that people are starting to understand rowing is a full-body, low-impact workout that exercises 85% of your muscles!

The Obsidian Surge 500 has many great benefits that you will discover below. However, like all products, it has a few downsides and some competition. Read below for the complete details on this model.

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Table of Contents
(click a title to jump ahead!)

1. Resistance Type
2. Monitor/Control Panel
3. Build Quality
4. Comfort
5. Storage
6. Capacity
7. Dimensions
8. Assembly
9. Pros and Cons
10. Consumer Reviews
11. Warranty
12. Price
13. Overall Review

Resistance Type

The Sunny Health & Fitness SF-RW5713 is a water resistance rowing machine.

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

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

The faster you row, the faster the paddles spin, and the more water they must move. So the faster you row, the more resistance you create!

We call this “variable” resistance because the amount of resistance depends on the speed at which you row.

This is the same way the resistance operates on air rowing machines. You can see how air and water resistance rowers compare to each other by reading my article here.

There are also “adjustable” resistance rowing machines such as magnetic and hydraulic-piston that you can learn more about here.

SF-RW5713 Obsidian Surge Resistance Pros

Water rowing machines create a smooth and quiet rowing stroke and that’s no different on the Obsidian Surge!

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

Users felt the resistance overall was smooth, even, and adequate for all fitness levels. One user commented that is wasn’t as strong as a Concept2 on a level 10 but it was more than enough for a great workout.

SF-RW5713 Water Resistance

One major benefit of water resistance is the noise volume is much lower than an air rower. People enjoy being able to row while watching TV or allowing other family members to rest without being annoyed by their workout.

A lot of users even find the water sound to be meditative and use it as a way to relax!

How to Increase Intensity

The water resistance on the Obsidian Surge SF-RW5713 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 also change the feel of the rowing stroke by adding or subtracting water from the tank. While technically this doesn’t change the “resistance” it does make the rowing stroke feel heavier or lighter. Sort of like rowing a boat by yourself or 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. However, some water rowing machines like the FDF Newport Challenge, have an adjustment knob that can transfer water between two chambers.

Resistance Overall

Overall the Obsidian SF-RW5713 has excellent water resistance that rivals any water rowing machine in it’s price range.

Users felt the resistance was smooth, strong and gave them a complete full-body workout. Plus, the sound of the resistance is pleasing!

The only issue some users mentioned is having to adjust the water levels manually.

Monitor/Control Panel

The Obsidian Surge 500 Water Rowing Machine comes equipped with the R2 Fitness Meter. This digital monitor is designed to track all essential workout metrics such as:

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

As you can see the monitor tracks more than enough data to get a great workout! Plus, it’s very well organized in easy to read sections.

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 setup and rowing fast!

Monitor Features

The Sunny Health & Fitness SF-RW5713 monitor has a lot of great features besides tracking a ton of data points!

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 bestselling 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.

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.

There is also a “Race” feature where you can select the pace of an “on-screen” digital boat and race it to the finish!

Monitor Downsides

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

One complaint was about the monitor not having a back-light and being difficult to read in low-light settings.

The other being a complaint about the accuracy of the data compared to the WaterRower and Concept2 models. While I understand this persons concern, they have to realize the SF-RW5713 cost half as much as the models they are comparing it to!

If you are looking for very accurate distance and calorie calculations, then yes, moving up to the Concept2 or WaterRower is a good idea. However, if you want to stay in the lower price range and have “good” and not “highly accurate” data, then this is a great choice!

Monitor Overall

Overall, the Obsidian SF-RW5713 monitor has received favorable reviews and not many complaints.

It can track enough data to keep a user engaged during a workout, while also being able to track overall progress as a user becomes more experienced.

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Build Quality

Build quality is such an important feature on mid-range rowing machines because it is often where you see the most negative responses.

It’s difficult for manufactures to balance the aspects of quality and cost when being stuck between high-end models and budget models.

Luckily, the Obsidian Surge 500 Water Rower seems to have their quality in order because it hasn’t received many complaints!

Surge 500 Build Quality

The frame is constructed from lightweight, sturdy steel and the 3 hydro-blades are made of stainless steel. This means no rusting or wearing down over time!

The water tank is made from polycarbonate plastic, which is extremely strong and durable. There were no issues with the tank breaking, cracking or leaking.

Users felt the seat, rollers, handle, and rowing strap were all made from high quality materials. The SF-RW5713 also comes with “leveling caps” so your rower always feels strong and stable.

Most users felt the footrests and strap were strong but a few did have an issue with a screw or weld breaking. Luckily, Amazon was able to ensure the rower was replaced without having to send the unit back.

Overall, the build quality on the Sunny Health & Fitness SF-RW5713 was excellent for a water rowing machine at this price! Check it out in action below:

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Comfort is another feature that is extremely important on a rowing machine. If you aren’t comfortable on your rower, you aren’t going to use it!

The Obsidian SF-RW5713 features a molded, padded seat to ensure comfort on long, hard rowing sessions. It is large enough for any user at 10.0″ x 12.5″ and it also sits 17.0″ off the floor. This taller than average seat height helps prevent people from putting extra stress on their knees and back when getting on and off the rower.

The seat sits on 3 sets of rollers and bearings to allow for a smooth, quiet rowing stroke. Users commented how the Obsidian Surge 500 was very quiet and you could easily watch TV while rowing.

SF-RW5713 Comfort

It is equipped with a non-slip sweat resistant handle that is wide enough to account for different grips.

The only controversial comfort design comes from the foot pedals. While they hold your feet comfortably in place, they do pivot as you row. Some people enjoy the pivoting foot pedals because they are not flexible and it helps with their ankle mobility.

However, others wish the foot pedals were fixed in place, like you see on the WaterRower and Concept2 models. One user even screwed them in place!

Overall, there were very few complaints about the comfort features of the SF-RW5713 Water Rowing Machine.


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Some users will leave the rower out when not in-use, so it can be easily used everyday. Others would like to save space and store the rower after each session.

These people are in luck because the Sunny Health & Fitness SF-RW5713 has very easy storage capabilities!

Simply lift from the rear and roll the rower forward on the high-density rubber wheels that prevent making any marks on your floor.

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

Surge 500 Water Rower Storage

Upright storage

The rower will rest 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!

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

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The Obsidian SF-RW5713 has a fairly large capacity and is in-line with most other rowing machines in this price range.

The seat rail measure 49.00″, which should be good for users up to 6’4″ tall. If you are over 6’4″, I would recommend measuring your inseam length and contacting the manufacturer to double check.

Sunny Health & Fitness Surge 500 Capacity

The weight capacity is listed at 250 lbs. but this is usually a conservative estimate. I would be comfortable saying someone who is 300 lbs. would be able to use this model without any issues. However, this technically would void the warranty and could come with more risk of injury.

Bill, one of our readers commented that after purchasing the Obsidian Surge he noticed the weight capacity sticker now says 300 lbs. While the website hasn’t been updated yet, I guess they have increased the limit!!

Anyone below these limits will be fine to use the Obsidian Surge 500. There are no factors that would inhibit shorter users or children from rowing.

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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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Assembly of the Sunny Health & Fitness Water Rowing Machine is fairly straight forward but will take about 45 minutes. I would give myself about an hour and plan on taking my time and reading all the instructions.

Assembling the rowing machine can be done by 1 person. The instructions are easy to read, the pieces are labeled, and it comes with all the necessary tools.

The most difficult part of the assembly is adding the water to the tank. You will have to use a bucket of water and the included pump with syphon hose. Just take a bucket of water, insert the pump, and beginning pumping the water into the tank. You can fill the tank to your desired resistance level, which is marked on the side. The tank holds about 2-3 gallons of water at max level.

The rowing machine comes with water purification tablets that you need to add to the tank to prevent the water from becoming molded.

After that, just pop in the 2 batteries that are included and you are ready to start rowing!

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Pros and Cons


  • Smooth, quiet water resistance
  • Adjustable water level provides strong resistance
  • Great price for water rowing machine!
  • Multi-function monitor is great for the price
  • Excellent build quality
  • Easy upright storage to save space
  • 17.0″ seat height for great comfort
  • Easy assembly


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

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Consumer Reviews

Overall the Sunny Health & Fitness SF-RW5713 Obsidian Surge reviews have been very positive. Consumers are happy to be able to purchase a water resistance rowing machine at a great price. They felt the build quality was great, it has a good monitor, and it is comfortable to row on.

There were very few negative comments and most related to monitor functionality and filling the water tank. However, most of these people were comparing the Obsidian Surge 500 to rowing machines over 2x the price!

Read here for more Obsidian Surge SF-RW5713 Water Rower reviews

Average Rating: 4.4

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

The 3-year frame and 90-day parts warranty is 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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The price on this Sunny Health & Fitness Water Rowing Machine is one of the main selling points. It is one of the lowest priced water rowers on the market and is a great blend of quality and cost. Sunny Health & Fitness only sells through 3rd party websites and is a very popular seller on Amazon.

I feel Amazon is a great place to purchase from because they offer great prices, free shipping on qualified orders, and a layer of protection between the buyer and seller.

Check current pricing discounts:

Check lowest pricing

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Overall Review

If you are looking for a very low cost water rowing machine then I think the Obsidian SF-RW5713 is one of the best options.

As I mentioned, it has great build quality, strong water resistance, and sells for a great price!

I rated it higher than it’s main competitor, the Stamina Wave 1445, because it has less quality issues. If you want to check out my Stamina 1445 review just visit my review here.

If you are looking for something with a bit more quality and a better monitor, then I would suggest the WaterRower A1 Home Rowing Machine or the First Degree Fitness Newport Challenge. They will be in the next price range up but can offer a few more advance features. 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 everyday, but it is more expenses. 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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