Don't just take what one or two people say as gospel and verse. Take the time and make the effort to find out what works for you and your team. .
Absolutely! Take caution with anything you see on the internet. Anyone can say anything they want and you have no idea whether or not they actually know what they're talking about. We've had a few of them in here before, eh guys?
Everything Mark says is good stuff. Not because I agree with it because I don't but its his opinion and it works for him.
I will comment on the BCD's however because my opinions have changed. Mark may remember that I had been on the fence about the back vs jacket inflate debate. I do a fair amount of tech type sport diving in my spare time and for that purpose the back plate and wing combination is by far the best solution for the reasons you've outlined - as a tech diver, we spend pretty much ALL our time u/w and the streamlining IS important for that mode of diving.
But for PSD there was always this question the wing pushing you forward into the water. Is this enough of a reason to abandon the wing type BCD altogether? I've since dove all kinds of different makes of wing (OMS, halcyon, deep sea supply, zeagle) and of all different sizes (from 27# to 65#). In my mind I reasoned that a smaller wing may not cause this effect so much. Here's what I found:
1) PSDs in particular tend to go for the really big wings (usually +55lbs). We don't need wings near that big for the rigs we dive (an AL80 + 19pony?) but we do need a bit more than a standard inflate if we're pulling victims off the bottom. Probably around 35-40lbs is good enough
2) It didn't make any difference in how big the wing was! I was tipped forward just as much with the little 27lb as the 65lb! The difference seemed to be in how full the wing was - a half empty wing had little effect but a completely full one would cause all kinds of trouble
3) The only way to really avoid the effect was to lay on my back and this could be done not matter how full or what size of wing.
Let's go back to what our job is and for this think of the scenario of the most stressful type of dive in your mind - night, winter in full rescue mode.
I agree with Mark that most of our in water time is spent u/w but what is the most critical time? In my mind it would be when we find the victim until we get him to shore. It is in that time where the diver is the coldest, tiredest and definately the stress and breathing levels will peak as soon as you make contact with the victim.
Because we are in rescue mode we will surface the victim and get him to shore asap - we don't wait for extra hands. Here's what will happen:
1) The diver makes a good ascent but needs BOTH hands to really control the victim so when he gets to the surface the BCD is pumped to the max - telling someone to only fill the BCD part way isn't going to happen. He is too excited and busy to worry about fine tuning his flotation on the surface. He'll blast the power inflator for all its worth
2) As I said earlier, I found the only way to combat the head forward tilt was to lay on the back; doing this while trying to manage the victim is very difficult at best. The diver will end up vertical and the head will be pushed forward into the water as was previously known
3) To combat the head from going into the water the diver has to use his fins. He can't use his arms - he has the victim. What's worse the weight of the victim will compound the effect even more and the diver must kick that much harder.
4) What about help? When do we send out the BU diver to help? Probably after he's on the surface because to send him to depth while the diver is making his ascent isn't logical. The point is the primary diver is already working really hard at the end of a stressful dive just to reach the surface. We logically would start to send the BU diver out when the primary diver is on the surface and already struggling with the victim. He could be as far out as 100ft (some teams will send their divers out even further than this) so we send the "help" (with the same floatation problem and now almost as stressed as the primary diver) probably as the primary is getting hauled in by the tenders. So lets say he only needs to actually go half the distance out.
I've thought that perhaps we might be able to send the BU out to the bubbles as soon as we get the signal from the bottom of the find but this may not always be possible - ie current, night etc.
Is this really enough time? All it takes is a teaspoon of cold water into the airway to cause immeadiate laryngospasm and asphyxiation OR the diver's grip may slip during his struggles and we've lost the victim and may have to search all over again.
I've seen this first hand in the
training of quite a few teams how much divers struggle in the water with these BCDs. Even in the pool divers will cramp up after just a few minutes of trying to remain upright at the surface. Adding the stress of a real rescue scenario would only make things worse. I believe in being streamlined in the water too but I think these factors grossly outweigh the small amount of streamlining that is gained by placing the bladder on ones back.
Trust me, I was probably one of the biggest proponents for the BP & wing as I was an avid tech diver long before I got into PSD and I pushed my team hard for us to get them and argued with the LGS big-wigs long and hard. But as I looked at it with an open mind and did realistic simulations its pretty hard to dispute. Try it for yourself - get a slippery mankin in the pool and make sure its weighted 16-20lbs (thats what we're dealing with) and let me know how you do vs a guy with a jacket BC
Heck, my own guys perfer the jacket after a few dives after using the zeagles for 5 years!
Just something to think about
mark
As for BCD's again keeping it simple is the common theme. This was one point that I really had to disagree with LGS. They are a proponent of the vest style BCD primarily because of the distressed diver on the surface scenario. If we dive the way they teach then there are always people around to assist if we surface in distress (safety, 90% diver, tender etc). We are not going to be on the surface without assistance for very long. Conversely we spend the most amount of our time under the water and having a comfortable streamline BC is very important. During the LGS class my team all had Zeagle Rangers which we all had been using for several years with great success and no problems. In addition to the rear inflation LGS also had problems with the integrated weight. After taking the training our team chose not to follow the LGS mindset regarding BCD's and we now all dive with Halcyon BCD's. They are very low profile and balanced in the water. Personally I have tried different amounts of air on the surface and have yet to feel like I am being forced face down. I attached a picture of me diving last week. You can see how streamline and clean my rig is.
