IDA-71 In The Bahamas

Mossyback

As promised a couple of months back, I said I’d let the IDA group how I made out taking my “71” to the Bahamas.

We flew out of Toronto, Canada on WestJet direct to Nassau with no problems. My O2 and diluent bottles went in our two dive gear bags and the IDA-71 went in a Fish Tote as suggested by Dave Sutton. I also put extra cable ties and a photo of me wearing the rebreather in the box. Each of our three bags weighed in at 57 pounds and WestJet allows 60 pounds per bag.

When the rebreather went through x-ray, the security person called me over to the screen and wanted to know what it was. I have to admit it really looked weird! I told her it was diving equipment and away it went. They did open it, because when I picked it up in Nassau, the cable ties had been cut on one handle.

From Nassau we flew charter to Fresh Creek airport on Andros Island – a 20-minute flight. We avoided a commercial link, as we didn’t want to endure a long wait in Nassau. A 15 minute taxi ride got us to Small Hope Bay Lodge where we had a week of great weather and three dives a day.

The staff was extremely interested in the “Russian Rig” and had encouraged me to bring it down when we were there last summer. They got my tanks filled – O2 and air so that I could dive it and loaned me a bailout bottle with reg. I had a defective bladder in my new BC and Mike the General Manager of SHBL, took the bladder out of his BC and gave it to me so that I could go diving. They’re a great group to dive with and want you to have the best dive experience possible. That’s why we keep going back.

As I had only tested it out in a swimming pool back home, I dove it conservatively, making dives of 70 and 80 feet. It performed well, no leaks and the manual feed for O2 (Dave Sutton design) worked to perfection. At depth I seldom had to add O2 as the continuous bleed (snubber?) kept me close to 0.5 on my O2 handset (Mark Munro electronics).

The WOB was a little heavy but not uncomfortable. If I was doing heavy work it could present a problem. I don’t see how I could overcome this situation even if I wanted to. Although I’ve added Drager hoses and DSV, the internal plumbing is still the original diameter. Besides, this is for recreational diving.

Perhaps the most valuable part of the whole exercise was figuring out what I liked and what I wanted to change on the unit when I got it back home. It’s now lying on my workbench or “slab” as Dave would call it, as I wait for parts to make my modifications.

Our week was great and Val and I got in both a wall dive (185 feet) and a new one (for us) – Church Windows (225 feet). Both of these were on OC.
Rebreathers are welcome at Small Hope Bay Lodge. Contact the owner, Jeff Birtch ahead of time if you intend to dive CCR so that he’s aware of what type of diving you wish to do.

Hank

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undrh2o

Thanks for the report - glad to hear it went well. What are the planned MODs likes/dislikes?

Chris

NEDIVER

Great report, any pictures?

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"slow is smooth, and smooth is fast" TM
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Dave Sutton

So we have positive data points on fish-totes as travel boxes, and cheap snubbers as orifices... great report! Glad all went well.

Dave

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SeaBass

Hank,

Great post! Glad to hear all the planning paid off.

But you know we've got to see pictures.

Thom

Mossyback

Hi Folks,

Yes, the trip did go well thanks to a lot of you making helpful suggestions. I only have one picture that I'll try and get scanned into the computer so that I can upload it. I borrowed an U/W camera from the local dive shop and Val got one shot of the 71 before the camera jammed. Just another motivation to get my Nikon into a housing.

As for mods - it's a little embarassing. Inspite of what I was told here on RBW, I tried to get both O2 and diluent tanks inside the housing. I managed it but the regs hung out. It didn't affect the operation of the 71 but it was difficult to put it down anywhere because of the regs sticking out. So ... if I go for off-board diluent (use a bailout bottle for diluent and BC), there's room inside for my O2. Doing this mod will also clean up the LP hose routings that I've been using. I'm also considering changing the OP valve set-up as suggested by Ken. Removing the hose from inside the CL will leave more room of the Delrin holder for the three O2 sensors.

Trim was another problem. I can easily fix it for diving up here by putting lead in the area of the CL. Flying, however, presents a weight problem.

On the positive side, (other than the stuff I mentioned in my original post), I really like the DiveRite Nomad harness and BC. I'm able to keep the unit stable and close to my body. I hate to have stuff shifting around when I move. The other mod that worked out well was the pee zipper in the CL. It nice to be able to easily take a peek inside and check the "T" and also the O2 sensors.

I'll have a shot at getting a photo up soon.

Hank

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jaap

Great!

I'm just curious did you run it at a pO2 setpoint of 0.5? I would say thats really on the low side.

I only played around a little with my 71 but I have a few ideas that could help:

Abot the WOB, for me the CL is really too big. So I added a big sheet of lead on top of the CL. Held in place against the top of chassis. It felt like this improved the WOB. By pushing the CL down the hydrostatic imbalance is reduced, sort of like a poor mans weighted bellow (as in the DCSC, PVR-BASC). It also cuts down a little on the excessive CL volume and improves trim.

If you want to restrict the CL a bit without adding a custom weight you could perhaps experiment by strapping the CL down with various lenght/strenght types of bungee cord?

To improve trim you could perhaps cut some slits and secure some ordinary weight belt lead (avaliable at any destination) in the top of the unit with some webbing and straps or simple tie wraps. I did this to several rigs. If you use straps or even lead pockets its quick & easy to take the lead off for transportation.

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Skipbreather

One combo weight/ trim/ WOB mod I’ve seen that is a subtle combination of the ideas mentioned in the above post: Zip tie a couple of those Velcro closure mesh-type weight pouches to the top inside of your lid over the CL. The zip ties should only be at the top of the pouches so that they can swing down freely when you’re horizontal. In that position the weight assists WOB per above post. When you’re vertical, the pouches hang toward base of rig and they don’t affect loop at all. When you travel, leave your lead at home and simply slip appropriate shot or block weight into pouches at your destination. This will be particularly effective once you remove the OP hose from the CL.

Ken

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Mossyback

Here are a couple of U/W pictures that my wife got before the camera quit working. You can see the problem with the reg sticking out at the bottom. The other one sticks out on the left side, so setting it down topside presents the problems that my mods will hopefully fix.

JAAP, I agree that the initial 0.5 set point was low. I later cranked it up to 1.2. I appreciate your suggestions re: the CL and the trimming situation. I'll try restricting the CL volume and see if the WOB changes. For diving when flying is not involved, I think I'll try a sheet of lead on the inside of the case, over the CL. I'll work something out for air travel so that I can use available weights at the destination as you've suggested.

Hank

Attached Images

	IDA U-W005.jpg (50.2 KB, 128 views)
	IDA U-W007.jpg (29.8 KB, 129 views)

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Mossyback

Hi Ken,

The trim pockets are a great idea, particularly for the air travel situation. I'll borrow some and try them out in the pool. The diving season here is still a month away.

By the way, I apologize to everyone for the size of the photos. I scanned them in as they were print film and got the size settings incorrect.

Hank

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"Be the kind of person your dog thinks you are."