Cave Diving, Cave Exploration and Cave Mapping in Yucatan, Mexico
Rebreather Diver at Chac Mool Cavern, Mexico

Spy photos of Rob’s Sidemount Prism Rebreather.

Okay, they are not really spy photos.  I emailed Rob after I saw his post on his wreck diving blog about his new sidemount rebreather and asked him some questions and if he had any other photos.  I thought that my “valued” readers would love to see more of his unit.   And I have my own selfish motives, I really wanted to learn more about his unit.  I think it is totally RAD!

One of the most popular questions I am asked is, “When are you going to sidemount your rebreather?”  My standard response is, “I am not planning on it anytime soon.”  That is followed with, “Why not, Hans?”  I usually answer, “Any place I would want to use my rebreather sidemount would require too much bailout to sidemount effectively.  It might work for survey where I need a lot of bottom time, but I might not be covering a lot distance.  However, I just haven’t felt the need.”  I think at some point, I might change my mind, just not today.  But I digress, the point here is that you want to see photos of Rob’s sidemount Prism rebreather.  Here they are.  Click the images to see a large version.

Rob ready to gear up with his Prism rebreather.Rob all dressed for the show in his sidemount Prism rebreatherRob entering the water at Dutch Springs with his Prism rebreatherRob in the water with his sidemount Prism rebreather
The unit is still in development in these photos.  Rob had some issues to work out, like the wing and the placement of his light canister.  My understanding is it is progressing nicely.  I asked Rob a couple of questions and here are his answers.

Hans: Have you dove it in the ocean?

Rob: I have indeed taken the sidemount rig into the  ocean.  Did two nice dives on the Arundo last Sunday, 100 minutes and 70  minutes.  Big bag oflobsters, 3.5 dozen scallops, plus an old  bottle.

Hans: How hard is it to kit up on the boat?

Rob: Kitting up is definitely different.  Put on the harness/counterlungs,  cinch everything up.  Sit down, butt clip both sides, hook up manual O2,  display and hud on one side, adv and wing on the other.  plug in the hoses  and connect, a bit of a pain but a one-click manifold is in the works.   Then bungee both sides and I’m set.  Easiest thing is on an engine cover,  barring that to just sit on the ground.

Hans: What modifications did you make to the Prism?

Rob: As you can see from the pics, I’m still wearing the standard counterlungs, just customized – Y-pipes, meg adv, inspiration opv, stock prism drains.

Hans: How is the work of breathing?

Rob:  WOB is the same as a stock unit.  The counter lungs are in the standard position, so I still get all the benefits of over the shoulder counter lungs.

Hans: What kind of weight do you need to trim the unit in the water?

Rob: Weight wise I am using:

  • Two 2lbs on top of the harness
  • A 3lbs and a 4lbs in the counterlung pockets.  (Prisms have these on the back.  Very convenient.)
  • A 5lbs in my right side weight pocket.  Nothing in the left.
  • The rig itself has a 3lbs and a 5lbs weight zip tied to the base.

I am possibly a bit heavy in this configuration, but not terribly so for salt water.  I can also use an AL80, in which case I can drop a few pounds.

Hans: Is it hard to turn off the O2?

Rob: It takes nothing to shut off the O2 as the knob is pointed right at my  hip. Can also unclip either side and swing it around in front of me to get through restrictions.

I want to thank Rob for allowing me to post his photos and his response!  And now for the extra special treat.  Here is a photo of a Prism (Right) and a Megalodon (Left) rebreather.  Both are sidemounted in the same fashion.  Click the image for a larger version!

Megalodon and Prism Rebreathers (CCR) Sidemounted at Dutch Springs NJ

If you want to see a video, I posted a link to Rob in his sidemount rebreather. If you have any questions you want me to ask Rob, let me know by commenting. I will follow-up and get responses as fast as possible. Safe diving and keep on pushing.


1 MK { 07.25.08 at 6:28 pm }

They do look like they are characters in a 007 movie.

2 Hans { 07.25.08 at 9:46 pm }


Your totally right! They look like something out of either Bond or Apollo 13. Can’t really tell if they are super heros or

I like to think of Rob as a Super Hero. He does some big dives and loves to stay down way longer then anyone I know. Even when it is cold!


3 Dan { 07.30.08 at 11:48 am }

would like to know if the t-pieces are available from ISC or some other mnf ?