questions answered
This post is from the comments you left on the last two posts.
My camera is rated to 130 feet because any deeper, the housing could crack or water could squeeze past the O-Ring seals and flood the camera. My old camera was rated to only 100 feet, but I took it to 170. At 170 feet, it didn't work though, I got a weird error on the screen and it wouldn't take a picture. I think it was being squeezed a bit. Maybe when the new gets worn off of this one I'll take it a little deeper, but I've flooded cameras before and it's no fun and expensive. I don't know why it's only 130 feet, it's just what the manufacturer says.
For the dive to 100 meters, the plan was 330 for 5 minutes, as we had an open circuit diver with us. (Two Inspirations and a tanker.) We used 10% oxygen and 50% helium for our bottom gas. (the open circuit guy had 12/60). 10/50 really wasn't really optimum for a dive of this depth on a rebreather, 8% O2 and 60% helium would have been better. Using a PO2 of 1 atmosphere, 10/50 should only be used to 298 feet.
It also should be noted that the open circuit divers gas bill was about $2000 CI ($2400 US) for 6 dives. Us rebreathers paid less than $100 for all our breathing gas for all our dives.
As you go deeper and deeper, nitrogen becomes more and more narcotic and oxygen becomes more and more toxic, so helium is added to reduce both oxygen partial pressure and nitrogen partial pressure.
Our runtimes were about 90 minutes, with the rebreathers clearing deco about 30 minutes before the open circuit diver. Run time is the time from when your head goes underwater till it comes back out of the water. It includes dive time and deco time. Our run times while planning the dive were about 60 minutes and his were about 90. Dive time is the time from when your head goes underwater till you begin your ascent, (330 feet, 5 minutes). But we stayed at 330 for about 5 minutes. (It takes about 3 or 4 minutes to descend to 330 feet) Everybody had computers and the profile was generated on land, and is really just a backup in case of problems. We stick to the profile, but the dive computers and the open circuit divers gas consumption gave us some flexibility.
The extra weight from the "Love Boat" helped me descend faster.
I'm not realy sure if we hit the sponge belt or not. I guess we did, but I'm not sure of the definition. At 330 feet, the dropoff is very vertical, so the sponges that like flat areas, like barrel sponges, are scarcer and not as big. But the sponges that attach to the wall and hang, like elephant ears and tube sponges are HUGE.
My friends left yesterday and today I'm studying and I really really want to go to the beach. Plus I have some personal business to attend to.
I'll get some pictures too
3 Comments:
Glad you posted! I thought maybe you imploded or something...
Thanks for the details, it's really very fascinating!
Nice post. Sounds like I'll have to get my butt over there and see these drop-offs for myself, they sound awesome!
My rebreather electronics packed in on Sunday so I won't have my Inspo for diving the wreck of the Russian liner 'Mikhail Lermontov' in a couple of weeks time... looks like I'll be a "tanker" for the trip!
i'm so jealous of you rebreather guys!
a bunch of guys at the dive shop i've been working part time for just bought and trained for megalodons. its just not fair.
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