Hollis Explorer backplate question?

[reefrat]

A quick question for any Explorer users:
Is the frame of the Explorer rigid enough to use with a soft backplate (in particular the Scubapro Xtec) or does it need the support of a rigid backplate?
Cheers

 

[davegster]

I don't know the definitive answer myself (I'm guessing that it would be, as you can get an Explorer with a jacket-bcd that doesn't seem to have a rigid backplate), but curious to know why you're asking?

 

[reefrat]

Thanks Dave
I would use the wing instead of a BCD but in order to minimize WOB with the back mounted CL's I want to keep the unit as close to my back as possible. My thoughts are to use a flat backplate like the soft scubapro one (or a flat aluminum one that I have) and an adjustable Xtec harness. The standard one piece harness and backplate would probably be OK but not ideal.
Also wondering how resistant the Explorer design is to a caustic cocktail with a user packed scrubber?

 

[davegster]

No worries - I just had some experience fiddling around with backplates on the Explorer when I was diving it and thought I could offer something useful

With a SS backplate, I didn't have any issues with the work of breathing at all - because the counterlungs are within the rigid framework of the unit itself, I don't think you'd gain much difference in positioning, whether you're using a soft or hard plate, though you might find the biggest difference would come down to comfort and personal preference.

I had to carry more weight with the Explorer compared to open circuit (probably less of an issue with lighter wetsuits etc - I was diving in 7mm semi-drys and drysuits) - the SS backplate helped a little with that - if you go with a soft plate, you might find you need more weight on your belt anyway - again, a bit of a personal preference.

Caustic cocktails - I don't recall there being any specific design considerations that would make it any more resistant than other types of rebreathers. The exhale counter-lung does have a fluid draining mechanism via the LCV which is meant to help keep the loop free of water. Assuming you're packing the scrubber correctly, it's as risk-free (or risky, depending on how you want to see it) as any other rebreather.

 

[TechDeep]

FWIW, my experience with WOB on the Explorer w/SS backplate has been that it has been fine, and as Dave said, I don't believe the gain you would see by getting rid of the SS backplate would even be noticeable, and not worth the tradeoff on comfort and added weight. For me, WOB has depended much more on my position in the water (trim). I put my heaviest weight in that pocket behind my head, and it works out perfect, unless I'm forced to use heavy thermal underwear under my drysuit. I find the biggest difference is getting my head down.

Come to think of it, if getting rid of the backplate meant you would have to put more weight on your belt, that actually could very well make your WOB noticeably worse! But, YMMV, so give it a shot and see how it goes. A flat aluminum, or other rigid plate should work fine, I see no reason why it wouldn't.

 

[reefrat]

Thanks Techdeep
Your comments on trim are noted and because I frequently dive a double hose regulator (Kraken) I already take care to establish a horizontal- slightly head up trim to achieve best WOB. Interesting thing about the flat back plate is that it just plain works without any discomfort from the nuts securing the cambands- I think the whole wedge shaped backplate thing is overrated and unnecessary.
Also, take a look at the rEvo website regarding back mounted counter lungs and getting the unit as close to the back (lungs) as possible, they make a big deal about it and the rEvo has very highly WOB for a back CL rebreather!

 

[TechDeep]

No problem, glad to help if I can. The only thing I can do is pass along my experiences, and hope someone can benefit from it. I actually started out on a Meg. This Explorer became available at a price that was hard to pass up. I think it's great for recreational diving, where the Meg would be overkill. But I digress.

I had very low expectations for the unit before I dived it. Everything I had heard about WOB w/BMCLs. It made sense because I have a buddy that had a Revo. I mean to me, there had to be some drawback to BMCLs, or everyone would be using them. Having the CLs right there in the way is just something I had to get used to on my Meg. I was very pleasantly surprised at the WPB of the Explorer. It was much better than I expected. For me, it hasn't been an issue at all.

Glad the flat backplate is working out for you. My remaining issue is getting my weight right when I am forced to use thick underwear with my drysuit. I haven't been able to find anything warm that hasn't been a nightmare for buoyancy. But it will be a few months before I have to deal with that again.

 

[muzikbiz22]

Dump the aluminum BP that comes with the Explorer, and get an SS plate. Us the Alum plate as your warm-water OC vacation rig. WOB is just fine on the Explorer.