I need help with my first twins: PST E-7 80s

[tangfish]

Hello, I just bought a pair of PST E-7 80s and I want to twin them up. I need a little help getting started since this will be my first pair of doubles. I know I need bands, a manifold, backplate and a new BCD setup. Problem is that there are so many choices to make. Can some of you who have more experience give a brotha a hand?! I'm looking at going with some OMS gear, mostly because it looks good and my LDS carries them.

A few questions to start out with:

- I've heard that I should get a rotating crossbar manifold, the ones I'm looking at come in both 200 and 300 bar versions. Do I need 300 bar?

- Do backplates come in different sizes and if so, what size do I need and what do I look for in a backplate? I've heard SS is better to go with but what weight and what features to look for?

- I hear that bands are very important. I don't know where to even start here. Since my tanks are smaller, do I need different types of bands to fit them?

- I'm looking at the OMS comfort harness and IQ pack, probably because they most closely resemble the type of BCD I'm used to, not for any other good reason. Any thoughts here? Also, these things look like you have to add so much to them. What size/lift bladder do I need?

- what about buying used gear, is it advisable? I'm not trying to pinch pennies here, I just want to get a good setup that I won't have problems with later, but something like a backplate doesn't look like it really "wears down".

Anything else I haven't thought of here? I'm 5'8" about 170 and dive a 7mm neoprene drysuit if that helps.


thanks in advance,

FS

 

[Mat4020]

Ill take a stab at a few of your questions

- I've heard that I should get a rotating crossbar manifold, the ones I'm looking at come in both 200 and 300 bar versions. Do I need 300 bar?

Do you have all DIN regs? The only advantage I see of a 200 bar manifold is the feature of having the ability to hook yoke regs up to them via a DIN plug.
I also would recommend an Isolation manifold, used in the event that you have burst disk or neck o-ring failure, you can shut down just one side.
As for leaving the isolation piece loose, I dont do it, I keep mine snug, but not too tight. Some like the idea so if it hits the ceiling of a cave (or anything else) it will rotate instead of possibly breaking the knob.

- Do backplates come in different sizes and if so, what size do I need and what do I look for in a backplate? I've heard SS is better to go with but what weight and what features to look for?

Some companies make different size backplates (I think Fred T does), but I wear a standard size that came from the manufacturer i use. I would look to make sure it have crotch strap slots (preferably the 2 inch as opposed to the one inch). And if you want to use an MC storage type pack, make sure it has proper holes for that. The holes in the center should be the standard 11 inches, so dont worry about that.

In my opinion a ss backplate is not needed with steel doubles, but you may need the extra weight being that you are in a neoprene drysuit. I use a alumn plate with my doubles (but they are 104's).

- I hear that bands are very important. I don't know where to even start here. Since my tanks are smaller, do I need different types of bands to fit them?

Highland Bands it looks like you might need model # 725. If you, or your dealer, contacts highland and tells them the tanks and manifold you will be using they will send you the perfect bands.

- I'm looking at the OMS comfort harness and IQ pack, probably because they most closely resemble the type of BCD I'm used to, not for any other good reason. Any thoughts here? Also, these things look like you have to add so much to them. What size/lift bladder do I need?

Im not a fan of OMS equipment, but the lift you will want is probably in the 40-50 lb range.


I hope this helps,

 

[xiSkiGuy]

- I've heard that I should get a rotating crossbar manifold, the ones I'm looking at come in both 200 and 300 bar versions. Do I need 300 bar?

You do not "need" 300 bar for the service pressure of HP 80s. I assume you are looking at the OMS manifolds and the burst disk service pressure is the same on the 200 and 300 bar manifolds: http://www.omsdive.com/valves.html
If you want to use yoke regs you'll need the 200 bar.

- Do backplates come in different sizes and if so, what size do I need and what do I look for in a backplate? I've heard SS is better to go with but what weight and what features to look for?

The OMS BPs you are looking at do not come in different sizes (the harnesses do). With a 7mm neoprene drysuit and HP80s, you'll probably want a SS BP.

- I hear that bands are very important. I don't know where to even start here. Since my tanks are smaller, do I need different types of bands to fit them?

Yes, you will need narrower bands to give you the ability to move the bands up and down on such short tanks. The bands will need to be designed for 7.25" tanks and be set at the standard 11" spacing.

- I'm looking at the OMS comfort harness and IQ pack, probably because they most closely resemble the type of BCD I'm used to, not for any other good reason. Any thoughts here? Also, these things look like you have to add so much to them. What size/lift bladder do I need?

Skip the IQ Pack. Not worth the price and you don't need the padding in a 7mm drysuit. If you want easy adjust-ability, go for the Comfort Harness. Most folks will suggest just using 2" webbing. If you want OMS wings, look at the 45# or 60# models. You don't need the 100# or the dual bladder models.

 

[kidspot]

if it helps here's a list of various bp/wing variations http://www.kidspot.org/personal/scuba/bpwing.html

I use Steel 72's and got 3" wide bands... while they are really nice, I wish they were narrower so I could move the tanks down another inch or so... fwiw

I use a 40# wing with my double 72's (lp 2250psi) and it's more than adequate... I'd guess that until you start going multiple stage bottles that will be the case...

For manifolds, I went with 200bar, however if there was no chance of ever needing to use the valves with yoke regs I would have gone with 300bar... This way I can break down the doubles and use them as singles in the future, which if a buddy comes along he will most likely have a yoke adapter. Easier to fill at most of the LDS over here too since they are not set up for filling DIN tanks.

As to used gear - Bands really can't go "bad" over time... If manifolds are bought used, you might consider rebuilding them. You might also check http://www.salvodiving.com/ as their prices seem to be quite good on things like manifolds.

Aloha, Tim