High Great SeaKool D2 Hands-Free Underwater Thruster review – you’ll glide through the water with the greatest of ease

We use affiliate links. If you buy something through the links on this page, we may earn a commission at no cost to you. Learn more.

highgreat seakoold2 5

CROWDFUNDING REVIEW – Have you ever power-snorkeled?  We have.  We did it in Grand Turk.  You don your mask and are given what amounts to a caged propeller with handles and a trigger.  Hold it in front of your body and pull the trigger.  The propeller spins and pulls you through the water.  It is great fun and easy to do.  There were issues for us.  The first is that you have this big, clunky thing out in front, partially obscuring your view.  Next is that it ties up both of your hands so carrying an action camera is out, unless you want to rely on a mask mount. In that scenario, you’ll have the propeller in every photo.  Finally, if you aren’t careful with how you orient the propeller, you’ll get a blast of rapidly-propelled seawater directed straight into your face.  Wouldn’t it be cool (or Kool) if you could just zip through the water like Aquaman so your hands are free to carry a trident, or more likely an action camera?  High Great, a maker of drones used to produce massive light shows, is expanding into water sports and wants to provide you with exactly that experience.  Today, we’re going to take a look at their brand-new underwater thruster system, the SeaKool D2.

What is it?

The High Great SeaKool D2 is a battery-powered waist-worn belt that features a pair of thrusters capable of generating up to 29 pounds of thrust.  This is designed to propel the wearer through the water at speeds of up to 4.5 miles per hour.

What’s in the box?

highgreat seakoold2 1

  • Storage box
  • Thruster belt with thrusters and controller attached
  • Battery pouch
  • Battery
  • Charging power adapter
  • Charger power cord
  • Startup guide
  • User manual
  • Warranty card (to be included with purchased units)
  • International voltage adapter with storage pouch (unclear if that will be included or was just included for this test)

Hardware specs

  • Main materials: Nylon, glass fiber, aluminum alloy
  • Total system weight: 16 pounds
  • Belt weight with thrusters: 10.8 pounds
  • Speeds: Levels 1/2/3 based on a 176-pound user – 1m/s – 2.2MPH / 1.5m/s – 3.4MPH /  2m/s – 4.5MPH
  • Nominal power: 500W
  • Maximum thrust: 29 pounds
  • Thruster speed: 3000RPM
  • Operating depth: 0 – 66 feet, 200kPa water tightness
  • Battery weight: 5.2 pounds
  • Battery: 13.6Ah, 25.2V Li-Polymer
  • Battery life: Level 1/2/3 – 120/60/33 minutes
  • Operating temperature: 32°F – 95°F
  • Charging: 110/240V, 100W dedicated charger, 3.5 hours

Design and features

highgreat seakoold2 23

The High Great SeaKool D2 Hands-Free Underwater Thruster is heavy and a little unwieldy to photograph.  There are a bunch of wires that are part of the system that make it difficult to pose nicely.  I’ll do my best to describe what you’re seeing.

In the photo above, you can see the whole system.  The large white items are the two thrusters.  These mount on your legs.  The box is the three-button controller that thrusts the system on/off and sets the speed.  Everything is mounted to a heavyweight canvas-like material.  It feels very well-made and sturdy.  All of the belt connectors are quick-release plastic connectors.  They clip together easily, stay put, and release easily with just a squeeze.

Here’s a look at the belt laid flat.  You can see the belt buckle clips on each side of the belt.  The battery connector is peeking out below the belt in the middle.  You can also see the leg straps on each of the thruster mounts. Two velcro-adjustable straps secure the thruster to each leg.

highgreat seakoold2 14

Here’s a closer look at the leg mount.

highgreat seakoold2 15

That center pad on the belt contains wire routing loops.

highgreat seakoold2 12

On the back of each side of the High Great SeaKool D2 Hands-Free Underwater Thruster’s belt, we find sets of really heavy nylon loops.  These are designed to hold the mounting straps for the battery pouch. You can purchase an additional battery and pouch to double the usable time.

highgreat seakoold2 13

The pouch is mounted on the belt and visible on the left in this photo.

highgreat seakoold2 11

The battery looks like a big can.

highgreat seakoold2 18

Weighing in at just over five pounds, the High Great SeaKool D2 Hands-Free Underwater Thruster is bulky.  Good thing the pouch to hold it is very sturdy.  The battery connector is located on top of the battery.

highgreat seakoold2 17

Insert the keyed connector into the socket on top of the battery and twist down the locking nut to make a waterproof seal.

highgreat seakoold2 19

The battery fits into the pouch. The battery connector sticks out of the flap.  The flap secures with another plastic clip.

highgreat seakoold2 16

The two thrusters have a large output port.

highgreat seakoold2 22

It narrows slightly to accelerate and focus the thrust.

Everything is controlled by the belt-mounted controller.

highgreat seakoold2 21

The buttons from left to right are power on/off, speed down, and speed up.  Below that are four LEDs.  The left LED in the power and speed indicator.  When you turn on the system, the multi-LED display lights up based on the remaining power.  The manual states that one LED means 20% or less power but doesn’t give any guidance for the thresholds for two or three LEDs.  When the unit hits 20% power, it will reduce speed to ensure at least ten minutes of operation so you can get back toward shore.

Once the High Great SeaKool D2 Hands-Free Underwater Thruster is powered up, pressing the “+” button increases speed, and the “-” decreases speed. The single LED changes color as well.

  • LED: red, speed 1, 2.2MPH
  • LED: green, speed 2, 3.4MPH
  • LED: blue, speed 3, 4.5MPH

highgreat seakoold2 20

To get a sense of how fast those speeds are, consider this. An average swimmer swims at about 2MPH.  Elite swimmers swim at about 4.7MPH over distance.  Elite swimmers in a sprint can hit 5.35MPH.  This means that the High Great SeaKool D2 Hands-Free Underwater Thruster can propel someone along at a regular swimming pace or keep them up with an elite swimmer over long distances.


There are four setup steps.

  1. Charge the battery
  2. Install the battery pouch on the belt
  3. Properly size the belt and leg straps for the intended user
  4. Place the charged battery in the battery pouch and connect the battery cable


After getting everything set up and sized for my lovely wife, we were ready to head to one of our local sports pools.  Below, she is modeling the High Great SeaKool D2 Hands-Free Underwater Thruster.

highgreat seakoold2 2

You can see the belt around her waist and resting on her hips with a thruster strapped to each leg.  You can see the battery in the pouch behind her right hip.

Here’s a closer look at the controller and a truster. The instructions state to make the straps tight, presumably so the equipment doesn’t move on your body.

highgreat seakoold2 10

She put on her snorkel, hopped in the pool, and got to scooting!

Here, you can see the output of the thruster when she was up high and picked up a little air in the intake.

highgreat seakoold2 8 scaled

She proceeded to cruise laps in the pool

highgreat seakoold2 3

The more she used the High Great SeaKool D2 Hands-Free Underwater Thruster, the more comfortable she became with it.  She opted for the high-speed mode almost the entire time.

highgreat seakoold2 4

She liked being able to cruise along with her hands out front or tucked by her side.

highgreat seakoold2 6

With her hands out front, she could use them to control direction as well as turn her body to execute turns.

highgreat seakoold2 9

She was able to effortlessly dive and then come back up at will.

highgreat seakoold2 7

Here’s a look at the thruster in action.

Based on the stated battery specs and the fact that she was operating at high speed for over 30 minutes, I expected that the High Great SeaKool D2 Hands-Free Underwater Thruster would die.  But much to our surprise, more than half an hour into the test, the battery indicator was still on three LEDs.  Based on that, the stated battery life of 33 minutes on speed 3 seems to be conservative. She does weigh less than the 176-pound user the spec was designed around, but the battery life still seems to be terrific. The manual says that it displays one LED at 20% battery or below, so with three LEDs, the display isn’t linear.  I guess I can assume that three LEDs mean 60%+ and two LEDs mean 20%+ or remaining battery life, but that’s a guess.  With 20% for one LED and 80% divided somehow between the other two, you will be guessing at battery life unless the battery is fully charged.  Regardless, we smashed through the expected 33 minutes with plenty of battery to spare.

Her feedback is that speed 1 felt quite slow.  But, if you’re out snorkeling and want to just look around as you go, it would be perfect for that.  Speeds 2 & 3 are better for getting from one place to another.  She told me all these things through an ear-to-ear grin.  She gushed about how much fun it was to use and that it was simple to turn as well as dive. She can’t wait to get to the ocean and try it out in an open area.

This is designed for users of average build.  Unfortunately for me, I do not fall into that category.  Being somewhat (OK, a lot) bigger than that, I simply do not fit into the belt, even lengthening it to its maximum length.  The leg straps are another issue as they certainly don’t fit around my thighs.  My wife can count that as a win as we won’t be fighting over who gets to use this the next time we go snorkeling.  She’ll be zipping around like the goddess she is while I’ll be pumping my flippers, trying to keep up.

When we got home, I filled our utility sink and tossed the SeaKool D2 in.  High Great recommends soaking the unit for at least 20 minutes in fresh water after use, especially in salt water. I drained the water and let it dry before disconnecting the battery and storing everything in the storage box.

What I like

  • It works well and provides a good selection of speeds for various uses
  • Generally comfortable to wear
  • Appears to be well-made and durable
  • It has a massive fun factor

What I’d change

  • I’d like to see a better representation of the remaining battery life on the controller
  • It’s heavy and bulky – not a problem in the water but an issue for transport to where you’ll use it, especially if flying
  • It would be nice to be able to position the thrusters more on the front of the thigh versus the side to reduce sucking in air

Final thoughts

The High Great SeaKool D2 Hands-Free Underwater Thruster is not yet a retail product.  It is currently in its funding phase running through the end of July 2023 on Indiegogo.  As of this writing, 12 backers have pledged over $12,000 or over 600% of their initial $2,000 funding goal.  Shipments are anticipated to go to backers starting this month, July 2023.  They are also offering the SeaKool P1, a single thruster kit designed to mount on stand-up paddleboards as part of this campaign.

Should you be excited about this?  That depends.  If you don’t snorkel or scuba dive, then probably not.  If you do either of those activities regularly, then I have to say, “Yes”.  Being able to spend a couple of hours doing either of those activities without having to exert yourself could make it more accessible to a wide audience of participants.  For those that can handle that kind of activity already, let’s factor in the fun factor and you have another audience.

Price: Perks start at $1299 (varies slightly based on the current exchange rate)  for early bird backers ($1690 retail), and $1559 for the pro kit with a second battery ($1997 retail)
Where to buy: Indiegogo – shipping is expected in July 2023
: The sample of this product was provided by High Great.

Leave a Comment

Your email address will not be published. Required fields are marked *