Halcyon or DSS rig?

[alexxred]

Hi All and thanks for the replies. Thanks for the offer to go diving, but I'm in Australia so maybe one day down the track.

I am diving with steel doubles, they are faber 10.5L. In regards to the angle of the plate I was juse curious if this made any difference when diving with doubles. I understand why the DSS works better for singles and was just curious if this would make any difference to its performance with doubles.

Originally Posted by NWGratefulDiver
"The DSS backplate has a very flat bend and shallow channel, which makes it an excellent choice for a singles configuration ... it'll put the cylinder closer to your body than a plate with a deeper bend angle.

Conversely, a plate with a very deep bend angle, like a FredT, is a better choice for doubles ... for much the same reason."

Seems I've had two different answers to that, although Tobin's seems to make the most sense.

Can NWGratefullDiver or anyone else explain why a plate with a deep bend angle would work better on doubles??

As for the wing still got some thinking to do on that one, but reckon that the torus would certainly be worth considering.

 

[GreenDiverDown]

I have looked very closely at how my plates sit on my doubles. I have numerous plates, including a DSS, FredT, and Halcyon brands. They each have a different bend angle as well as center channels of different depths. The FredT plate has the most acute bend and the deepest channel, the DSS plate is the flattest and most shallow, and the Halcyon is somewhere in the middle.

It would seem that the plate with the most bend would allow the body of the diver to sit back further between the cylinders. This would have the effect of bringing the cylinders and the valves closer. But in reality, I do not believe that this happens. If you look where the diver's back contacts the plate you will see that it this occurs on the flat part on both sides of the channel. On all of these plates this 'flat part' rest firmly against the cylinders and in about the same position. The only difference is in the thickness of the plates and this is relatively small.

If you don't believe me, then simply take a look at where your back contacts a set of twins without a plate. You will see that this contact does not occur deep between the cylinders but closer to the very front plane. There is no way that a plate with a greater bend is going to significantly change the location of the contact point.

Though this may be a bit of an exageration, it may still help you visualize what I'm talking about. Place your twins against a wall. Where does the wall come in contact with the cylinders? Not in between them...right? Now think of your back as the wall.

Perhaps if our bodies were more triangular in cross-section or if we were bean-pole skinny then we could nestle further back in between the cylinders with plates of sharper bend!

 

[cool_hardware52]

What I have learned about plates and bend angles:

First it needs to be understood that plates fit the diver differently when diving doubles vs singles. At first glance this seems a strange statement, but it's true.

Double tanks are close to the divers back, regardless of bend angle, seperated from the diver by basically the thickness of the plate. This means that the lower edge of the plate may not contact the diver at all! Instead the lower end of the tanks hit the diver in the rear.

With a single tank this is not the case. Because the tank is spaced away from the diver by the center channel the plate will contact the diver at the lower edge.

I found, while developing our plate, that a flatter plate was more universally comfortable, when rigged with a single tank. By this I mean a wider range of divers, height, width, male, female, found a flatter plate comfortable.

I also found that a given plate that caused complaints when fitted with a single tank, did not when fitted with doubles, for the same diver!

If you want confirmation of this, just look at many of the plates sold today, they have two "extra" bends at the lower corners. Why? because they are so steeply bent that the lower corners dig into your back, when used with a single tank.

It is not surprising that plates are steeply bent, they were of course originally developed for doubles (where steep bends are not uncomfortable)

What are the limits to making the plate flatter? If you want to mount doubles you need space for the bolts and wing nuts. These fit in the center channel. Shallower plates (like a DSS for example) may require slightly longer bolts than some steeply bent plates, but never so long as to present a risk of contact with the diver.

All my doubles are set up so that the bolts on the bands do not protrude beyond the tanks. In other words if one places a straight edge across the tanks the tip of the bolts will be ~ .25" below the straight edge. This lenght allows the plate to be secured and still keeps the fasteners well away from the divers exposure suit.

(I should point out that even if my tanks are used on a steeply bent plate the bolts will never be closer to the diver, they just stick through the plate further.)

In short the only advantage I've found to a steeply bent plate was when trying to fit doubles with very short bolts. There may be others but I have not seen them.


Regards,


Tobin

 

[limeyx]

A Halcyon bp would require a STA if used with the Eclipse wing. A STA is not needed for a Pioneer wing (as it "incorporates a built-in single tank adaptor welded into the "backbone" of the wing").

yes, but bear in mind that the built-in STA makes it a pain to switch from singles to doubles (you have to keep removing & inserting the bands through the BP)

 

[limeyx]

Hi All,

...

3. The inflator, I've read that Halcyon has had issues with theirs. Is this something to even be concerned about??

Cheers

Alex

The new Halcyon wings come with stainless steel inflators. If you plan on diving in salt water, the best thing (in my opinion) is introduce the steel inflator the the trash can and put on a cheapo plastic one. I and a buddy have had two steel ones "leak" and i know other people with the same issue.

I have heard the inflators are OK if you "service" the inflator every 6 months (dont know as mine didnt last that long!)

 

[WaterDawg]

1. In regards to the SS BP themselves, I notice that both do not require a STA. DSS points out that due the angle of their BP, it is a better choice if diving singles. Is this the reason that Halcyon also does not require and STA, or is their configuration (angle of the BP) different again??

Like someone said the need for an STA depends on which Halcyon wing you get. a Pioneer does not need it but an eclips does

2. The wing - I'm pretty sure that I will only need the 40lbs lift, If I went with Halcyon I'd get the 40lb Evolve wing as the 60lb would be over-kill. If I went with DSS I'm faced with two options either the 50 LCD or their Torus 45lb. The main thing that I wondering about here, especially when compared to the Halcyon setup is that the the DSS has no zipper, and therefore less failure points. The lift is also closer to what I need. But if something happens repair wise, say a pinched bladder, am I'm better off with the Halcyon as this can be accessed easier to be repaired??

The Torus is the same width as the Explorer 40, so more than the Evilve. You CAN accsess the bladded on both, w/ the DSS is thru the velcro.

3. The inflator, I've read that Halcyon has had issues with theirs. Is this something to even be concerned about??

Starting Jan 06 Halcyon is going back to the plastic inflator. So no worrys either way