Safety Questions

[TSandM]

Hey, guys! In whose open water class was anybody taught how to calculate rock bottom for a 110 foot dive? We go over basic gas planning in our OW class, but the mechanics of calculating an appropriate reserve are not really part of it -- the diver is more or less GIVEN a reserve number, based on a 60 foot dive. And although we do tell our students that LP leaks will empty a tank faster than HP leaks, we don't go into the numbers. An OW diver with a significant leak should be aborting the dive, period.

I don't think the OP's questions are bad questions. I do think doing spearfishing dives to 110 feet as a brand-new open water diver is something which is probably ill-advised. I haven't done those dives, but my understanding is that they frequently involve significant exertion and are almost always executed essentially as solo dives. Putting a novice diver at that depth, with the typical high consumption rates of new divers, and setting that diver up to be alone, seems to me to be a bad scene. But if the OP has ambitions to do that type of diving in the future, after gaining some experience, then his questions are, to me, completely appropriate, and deserved thoughtful answers.

 

[WB2GLP]

You may take issue with some of the replies you've received, but their points are valid. As an open water diver, regardless of agency, you've been trained to a max depth of 60 feet. Diving beyond your training and experience puts you and your dive buddy at risk. That being said and apparently falling on deaf ears.....

If you were a well seasoned diver who was certified beyond open water and looking for redundancy, I would recommend 30 CF at minimum. As a new diver, you must also figure panic into your air consumption equation. If and when the s#!t hits the fan, your air consumption will be through the roof.

 

[uncfnp]

Good for you for looking for answers to make you a safer diver. You describe yourself as a "complete newbie" and for good reason. You have a lot to learn. And I also disagree that your questions should have been addressed in OW. OW does not prepare you for your dive plan. Not in any remote way.

And why the hurry? Is this a one time opportunity? Take the others suggestion to slow down, develop your dive skills. Ask more questions here and try to be open to the responses. They are not always sugar coated but usually they are well meant and often valid.

So my answer to your questions.

1) with the little info we have, sling a 30 at minimum and know how to use it. Open it on the surface and leave it on. You are very likely to need it. I am not being snarky. The previous posters are right. You will lose track of time and gas and you will go through that gas quickly.

2) My understanding:

at 4 ata...

burst disk...72 seconds
ruptured HP...22 minutes
ruptured LP...83 seconds
freeflow...155 seconds

Don't count on a buddy. Speros are solo. Grap your redundant and head for the surface.

 

[cgm73]

burst disk...72 seconds
ruptured HP...22 minutes
ruptured LP...83 seconds
freeflow...155 seconds
These are the answers im looking for. I am aspiring to this level of diving not . Im going to probably stay around 60ft for the rest of the summer to get more experience before I continue my training. As for as computer i have a Mares Smart computer and am proficient with it. I will keep reading and expanding my knowledge, but experience is what i am lacking. thanks for the help.

 

[dumpsterDiver]

burst disk...72 seconds
ruptured HP...22 minutes
ruptured LP...83 seconds
freeflow...155 seconds
These are the answers im looking for. I am aspiring to this level of diving not . Im going to probably stay around 60ft for the rest of the summer to get more experience before I continue my training. As for as computer i have a Mares Smart computer and am proficient with it. I will keep reading and expanding my knowledge, but experience is what i am lacking. thanks for the help.

GOOD! You just need to get a small pony bottle and you don't have to worry about all these failures. Then you need to learn to dive and then to spearfish. Spearfishing is so much different than "just diving" it s probably hard for some people to understand. It can be a lot of fun, but can also be extremely distracting, so to be reasonably safe, you need to get the diving down so well that it is routine.

For myself, a solo dive to 200 ft (on air) to take some video, is much less challenging than spearfishing in 125 ft in many of our local spots. Don't underestimate how quickly things can get out of control with spearfishing.

 

[Dr. Lecter]

GOOD! You just need to get a small pony bottle and you don't have to worry about all these failures. ...
Don't underestimate how quickly things can get out of control with spearfishing.

To that I would add practicing with the pony enough that deploying it unexpectedly and under stress is smooth and unremarkable; it's one thing to stick a handgun in a holster and walk around with it, and quite another to be able to properly draw and present when suddenly confronted with a problem.

Dumpster, don't you have a good video somewhere of a spearfishing dive that went sideways when the fish wrapped you in your own line?

 

[cgm73]

I will practice enough with the pony bottle to be very comfortable switching to it if i decide to go that route. I dont see many spear fishers using pony bottles is there a particular reason why, am I being overly cautious?

 

[dumpsterDiver]

I will practice enough with the pony bottle to be very comfortable switching to it if i decide to go that route. I dont see many spear fishers using pony bottles is there a particular reason why, am I being overly cautious?

Because way, way too many spearfisherman are freaking cowboys and don't really give a crap about safety. My buddy won't wear a pony on 130 ft dives, but I told him I won't dive with him to 180 , if he doesn't borrow my 13 cu-ft tank.

You have to realize that the activity of spearfishing is very dangerous, the incremental danger from gear failure to a very experienced spearfisherman is not so great. Never the less, I personally always carry redundancy, but i have seen people die, i have seen people be stuck using a walker forever - from diving accidents.

For me, it is stupid to not take a pony that will at least keep you from drowning. But there are some very good and experienced divers who hunt over 200 or 230 ft on a single 80 tank.. and they get away with it over and over again - even though they have friends who have not.

A pony is more drag and some weight.. you need to decide how important it is. I mean i have been driving to the same place for wok for like 15 years,,, never had an accident and never needed my seatbelt. Yet, I (usually) keep putting it on- even though it is a short commute at speeds less than 45 mph. Redundancy is like a seatbelt.. you don't really need it - unless you do.

If you are diving with people that are going solo over 100 feet, you need to realize that they probably will not have a good outcome if they have a total scuba failure - especially if they are winded and chasing a fish.. they will die.. not much more to it.

 

[cgm73]

Quick Question about pony setup. If i have a zeagle Octo z breather as reserve regulator and a 13cu pony bottle is it feasible to have a quick connect hose leaving the pony first stage and following the same path as the quick connect line on main tank to Octo z. If catastrophic air failure on main tank ie oring blow out regulator free flow etc., disconnect Octo from main tank and hook to pony tank quick disconnect line. This should reduce extra equipment. From what I understand spear fishing you want as less equipment as possible. This will not work if Octo z has the failure unless I have quick connect on main regulator also to do the same switch. I can't foresee both regulators going out at same time. I'm very particular about maintenance and upkeep especially when it comes to my life. Thanks for all the help if this will work I will post pictures of completed project.

 

[dumpsterDiver]

[video=youtube;j0sdSL-ng-g]https://www.youtube.com/watch?v=j0sdSL-ng-g[/video]