when do you use a pony bottle?

[dcs917]

Although lots of room here for personal preference (search the Board) I use a 30cf AL Pony clipped to the left side of my BP/W when diving over 60'. Typically run 40% Nitrox (MOD 99'), and do not use except in case of bailout. I believe in the 150% rule for tank selction, and assume the worst. Clipped bottle can be handed off in case of buddy emergency.

DSAO

 

[jeckyll]

You calculate your MOD on the contingent depth? Just curious as I'd have stuck with the 82...

 

[dcs917]

Yes, since this only a bailout emergency situation, I use a more aggressive PPO2. So, MOD = ((1.6/.4)-1)*33' = 99'. You should make your own choices however.

 

[mirrocraft]

for a short flush with a higher o2 mix (nitrox) to shorten deco times