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Rebreather Diving (With my Prescription Dive Mask) on the Fu Sheng Wreck in Sint Maarten

Rebreather diving in Sint Maarten

One of the ways we are differentiated is the fact that we are divers, not just opticians and optical techs. While the last two years have been challenging for us and others in the dive industry, I was finally able to start getting back in the water this year. The video above highlights a recent awesome dive we we are able to do on a wreck in Sint Maarten. For those wondering, I dive a prescription scubapro d mask with single vision lenses. 

I like to write about some of my dive travels with my own prescription dive mask and share them with you all.

In this article, I will also cover specific prescription dive mask concerns for rebreather divers.  (Be sure to check out my video above highlight the whole dive).

Dive mask and scuba equipment.
My Scubapro d mask with prescription lenses sitting on my Hollis Prism 2 rebreather.

What is a rebreather?

A diver underwater with a rebreather diving along a wreck
Aiar diving his prism 2 rebreather on the Fu Sheng wreck in Sint Maarten

In Scuba, we have a compressed air tank attached to a diving regulator (a first and second stage). Every time we inhale the regulator provides us (normally) air (or nitrox, or even other gases, depending on the dive) at the surrounding pressure, so our lungs can inflate. Every-time you exhale, all the air in your lungs exits the regulator as bubbles. The human body, however, is not so efficient as to extract all the available oxygen in a single breath of the same gas, so the bubbles contain a significant amount of wasted oxygen. If there was a way to recycle this air, you could extend your time diving.

On a simple level, this is what a rebreather accomplishes. Instead of all your exhaled air exiting as bubbles, you exhale into a counter-lung. The exhaled air then moves across a scrubber removing the carbon dioxide. As the oxygen in the breathing loop decreases, you either manually add, or the rebreather adds pure oxygen to the loop to keep your breathing gas at an ideal mixture. 

Prescription dive mask concerns for rebreather divers

If you are a rebreather diver, and like me need corrective lenses, there are a few unique concerns that open circuit divers don’t face. 

While heads up displays and computers for recreational divers have recently seen a surge in popularity (like the Scubapro Galileo HUD), they are a mainstay in rebreather diving. Rebreathers either utilize a heads up display (HUD) with a series of different color lights to indicate different rebreather conditions or a computer with a full digital display that can provide more information than the more basic HUDs. The most popular HUD computer is the Shearwater NERD, which I personally use on my Prism 2 now. 

The shearwater NERD uses a special lens to focus the display when the diver is looking at a distance, despite the computer sitting inches away from the diver’s face. This allows the diver to be watching his or her surroundings while also having the dive computer screen in focus. If the diver utilizes bifocals or readers in their dive mask, however, the near vision portion of the lens is not suitable for viewing the NERD (While beneficial to a standard light HUD). For rebreather divers who utilize bifocals or reading glass for near vision, we generally suggest using only distance lenses on the side of the mask they view the NERD (normally the right eye).  For more information on our bifocal lens scuba mask options, please read my article here. 

We are also able to produce fully customized lenses that include a reading section at the top of the lens instead of the bottom of the lens, where the NERD is placed, so the diver can use the top of the lens for photography or other macro work. 

Whether you dive a rebreather or open circuit scuba, our diving experience allows us to help you pick the right prescription lens for your needs. Feel free to give us a all or shoot us a message. Our prescription lenses are installed in house in our lab in Houston and are able to provide corrections for astigmatism, double vision, and other unique needs.

The Fu Sheng wreck in 110 feet of water in Sint Maarten- A great dive for a rebreather.

Diving the fu sheng wreck in Sint maarten/st. martin

A dive boat on the surface of the water
Dive Sint Maarten's boat waiting for us at the surface following our hour long dive on the Fu Sheng wreck.

During my time on St. Martin, I dive the Fu Sheng wreck, a dive I have been trying to do since arriving on the island. The wreck, nestled in about 110 feet off the coast of St. Matin, remains largely in tact. The wreck sank unintentionally, and is one of the older wrecks on the island.

The wreck hosts a variety of marine life including garden eels, moray eels, rays, and a mix of coral.

Diving the wreck on my rebreather allowed me a dive time of just over an hour with only a short deco time of 20 minutes on the way to the surface. 

Additional resources

For diving in St. Martin, I have used both of these operations, which have supported rebreather diving (and recreational open circuit). I do not receive anything in exchange for recommending them, and I found them to both be great dive centers.

Ocean Explorers Dive Center in Simpson bay

Dive Sint Maarten in Philipsburg


Picture of Josh


Josh is an optical technician and owner of See the Sea RX. He is a PADI instructor and rebreather diver- he has been involved in diving for more than 20 years. He has also worked as a sergeant at the Harris County, Texas, Sheriff's Office, which included time as the instructor for the dive team. Josh also holds a masters degree in data analytics from Texas A&M.

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Diving the Cenotes in December

See the sea rx, diving the cenotes

One of the joys of being in the diving industry is diving! Unfortunately, we have to ensure our customers are taken care of, and as we grew tremendously in 2019, I was unable to dive as much as I would like. In December, 2019 (pre covid days), I was able to duck down to Cancun for a quick vacation (just a few hours flight from our base here in Houston).  The trip was great, and I want to share a few pointers from it:

  • Diving the Cenotes (and open water)
  • New Ikelite Housing/Camera Test
  • Trying out Atomic Masks
I also put together a video on the diving, which you can check out below:
Scuba diver underwater wearing Atomic brand twin window lens mask looking at the camera.
Josh trying out the Atomic Subframe mask in Cancun

Diving the Cenotes- Josh's video

In Cancun, you have two major options for diving: open water and the cenotes. The reefs in Cancun are not as well known as those in Cozumel, but the diving is still pleasant. They also developed an “underwater museum” which allows divers to explore interesting views and sculptures while giving the reefs a break from the divers. 

Divers also can head south from Cancun to various cenotes where fresh water diving systems extend throughout the Yucatan. The above video I took focuses mostly on the cenotes. The Cenotes offer access for various skill levels including swimmers through technical cave diving. The diving I conducted on this trip is available for most certified divers and considered “cavern diving”. While there are times the diver cannot ascend immediately above them due to cover, the diver can at all times see an entry and exit point (light). Divers conducted cavern diving should be accompanied by a certified cave diver.  On this trip, I dove with Cancun Scuba Center and Juan Carlos. I did not receive any discount for diving with them (or posting about them here), but I always enjoy diving with them. 

Testing out cameras

Photography and underwater photography have always been a big passion of mine. In the above video I used my trusty Canon 5DmkIV for the above water shots; however, I tested out a new camera for underwater video and stills. See the Sea RX became Ikelite dealers in 2019, and one of the cameras I have wanted to test is the Sony RX100VI due to its small size and overall great reviews as a travel camera. There are now newer version of the camera available, but it is still compact powerful travel camera. I did use an external ikelite flash. I have included pictures from both the Cenotes and the open water diving I did below for you all to see. As a side note, if you are doing underwater photography (And use bifocals or progressives), you can check out my article on bifocal dive mask lens options for some suggestions.




Testing out masks

I dove two masks on this trip, both Atomic masks, as I have not tried either (and we are the home of ordering Prescription Dive Masks). During the whole trip, I did have stubble/facial hair, and I did not have problems with leaking in either mask. I dove with the both the Atomic Venom and the Atomic Subframe. I have discussed both these masks in my posts on prescription lenses for atomic masks.

While I do personally prefer twin lens masks for aesthetic reasons, I do see why the Atomic Venom (Frameless) has become one of our most popular masks as it was incredibly comfortable with a wide field of view. I have heard some complaints from other divers about fogging in the venom. After a full prep including burnout, I did not have any issues with fogging in the mask. KEEP IN MIND YOU SHOULD NOT DO ANY BURNOUT WITH OUR PRESCRIPTION LENSES, and in general we do a full prep in house. 

I also enjoyed diving the Atomic Subframe which is a twin lens mask. I found it to be sturdy and have a comfortable seal. The Subframe will likely remain my personal diving mask for some time. 

Picture of Josh


Josh is an optical technician and owner of See the Sea RX. He is a PADI instructor and has been involved in diving for more than 20 years. He has also worked as a sergeant at the Harris County, Texas, Sheriff's Office, which included time as the instructor for the dive team. Josh also holds a masters degree in data analytics from Texas A&M.