About to dive Poling for first time!

[DavidInNH]

Tomorrow I will be diving the Poling for the first time and am really looking forward to it. I'll be diving an AL-80 with 28% Nitrox mix. Bottom time (according to my calculations for a 100' depth) goes from 19 minutes to 25 minutes with this mix. My guess is that my bottom time will not be limited by nitrogen uptake but more likely by tank capacity. I'm thinking that I should begin my ascent when I hit around 1000 PSI. That should give me plenty of gas to reach the surface including a good safety stop.

How do you other fine folks plan this dive?

 

[Sharky1948]

v-planner gives you a 4 minute stop at 10' after a 25 min dive and, assuming a RMV of .8, requires 90 cft of gas. So, you're right, you'll be limited by gas.

Leaving the bottom with 1000 should be fine...IF you have a redundant air source. Are you slinging a 40 or something? My personal opinion is that you should not do that dive without the redundant air source.

BTW, I assume you're diving the stern. (The bow is a bit deeper than 100fsw...)

Dive safe!

 

[DavidInNH]

My only redundancy will be my buddy. My typical RMV is in the .65-.7 range and I think I'm building in a little extra safety since the max depth of 100' is in the sand and I will more likely be in the 80-85 foot depth range. Sounds like I should be okay. (Although, I'm thinking a pony bottle will be in my future.)

Thanks for the reply!

 

[Skeeter1097]

have fun, numbers look good to me.

 

[Rainer]

Tomorrow I will be diving the Poling for the first time and am really looking forward to it. I'll be diving an AL-80 with 28% Nitrox mix. Bottom time (according to my calculations for a 100' depth) goes from 19 minutes to 25 minutes with this mix. My guess is that my bottom time will not be limited by nitrogen uptake but more likely by tank capacity. I'm thinking that I should begin my ascent when I hit around 1000 PSI. That should give me plenty of gas to reach the surface including a good safety stop.

How do you other fine folks plan this dive?

What stops do you plan to do? I'd leave myself a bit more gas to do my ascent (min deco) from the Poling, and I'd also be taking at least 100cf. Finally, any reason you're only using 28%?

 

[DavidInNH]

Only using 28% because I'll be diving with a buddy on air so I won't really get any additional bottom time. Also, not sure what the other dive will be. 28% gives me margin to 130' in case we do a deeper first dive. (More likely, it will be a shallower dive but I don't know for sure.)

In any event, I COULD use air but figured to get the additional safety.

 

[Soggy]

The reality of the Poling is that it's not a 100' dive. The sand is about 95', but you can do a dive on the deck as shallow as 75-80' if visibility is decent. When I dive it, I use a 90' average depth since, even if I spend some time down in the sand, more time is spent on the more interesting deck.

You definitely will be limited by gas rather than time on this dive. An al80 is not a real good choice for cold water diving at these depths. It'll get you there and back if you plan it real conservatively, but you'd be better off with a larger tank.

 

[Belmont]

The reality of the Poling is that it's not a 100' dive. The sand is about 95', but you can do a dive on the deck as shallow as 75-80' if visibility is decent. When I dive it, I use a 90' average depth since, even if I spend some time down in the sand, more time is spent on the more interesting deck.

You definitely will be limited by gas rather than time on this dive. An al80 is not a real good choice for cold water diving at these depths. It'll get you there and back if you plan it real conservatively, but you'd be better off with a larger tank.

I concur, using the rule of thirds would leave even less bottom time on an al80

 

[Tampico_ED]

Hi,

Despite the fact that you can use a higher concentration of gas. 28 is alright...I will advice if you have the two tanks at the same EAX then the first dive go deep all around the bottom of the ship (only if vis is ok)....do not forget to look for goodies and a close look to the opening....if you still have time left ascend to the deck and sniff around.

On the second just browse on the deck and spend more time do not go to the sand....well that's I have found to work better while diving this wreck.

AND DO NOT FORGET to check out by pictures...
http://www.scubaboard.com/showthread.php?t=180174&highlight=polling

http://www.scubaboard.com/showthread.php?t=184953&highlight=polling


Good LUCK !

Tomorrow I will be diving the Poling for the first time and am really looking forward to it. I'll be diving an AL-80 with 28% Nitrox mix. Bottom time (according to my calculations for a 100' depth) goes from 19 minutes to 25 minutes with this mix. My guess is that my bottom time will not be limited by nitrogen uptake but more likely by tank capacity. I'm thinking that I should begin my ascent when I hit around 1000 PSI. That should give me plenty of gas to reach the surface including a good safety stop.

How do you other fine folks plan this dive?

 

[Soggy]

I concur, using the rule of thirds would leave even less bottom time on an al80

Rule of thirds isn't really a valid planning device for square profile dives. Rock bottom is what you need to be using.