BP Orientation

[JBFG]

probably a stupid question but what's the orientation that the B should be?

let me clarify, the center of my dive rite PB has a bump. does the bump go against the back or does the cavity goes against the back.

I can't see the bump going on the back as it wouldn't be confortable, but again I can't see the tank going on the bump as it wouldn't be stable.

 

[buddhasummer]

The "bump" goes against the tank and the flat or "cavity" part against your back. The tank is sandwiched against the wing or STA if you're using one and held securely by the tank cam bands, it is stable.

---------- Post added August 31st, 2013 at 11:33 AM ----------

This video might make things clearer for you. If you have any more questions ask away. Good luck.

Browse Videos equipment: bpw Videos on ScubaDivingTube

 

[JBFG]

ok thanx!

 

[halocline]

I can't see the bump going on the back as it wouldn't be confortable, but again I can't see the tank going on the bump as it wouldn't be stable.

It's a great question that's answered by realizing that backplates were originally designed for double tanks, and the ridge existed to accept bolts from the doubles' bands without poking a large wing nut into your back. When people started using plates for single tanks, they designed "single tanks adapters" (STA) that used the same bolt holes to mount an adapter for the cam bands and to cradle the single tank.

Eventually plates started including slots for cambands so the STA was not necessary, but to keep the plate useful for both double and single tanks, the ridge remained. Some wings incorporated stabilizers to help line up the tank and keep it still. If the cambands are tight, the tank's not going anywhere with or without stabilizers in the wing. Then a few companies started making plates for single tank use only; one of these was the jet harness plate which was dead flat and surprisingly comfy. Another more recent is the excellent 'freedom plate' made by Eric S on this forum; that plate is somewhat based on the shape of the old pre-jacket BC plastic plates that divers used decades ago.