BP/W: I officially don't get it

[MSilvia]

Pick up those knees Jim!

 

[halocline]

I am not in any way opposed to the use of backplates, but to the idea that there isn't any sensible alternative.

I like your attitude and despite my conviction that BP/Ws are a far batter design than jacket BCs for diving, I agree that each diver should find his/her own preference, and some people will prefer using a jacket.

 

[Adobo]

Here is a diver that is just ok in the water but you can see the difference from RI to BP/W. Take it easy I know the diver!

Rear inflation / steel hp120 / 4lbs added / 80 feet / Cozumel

BP/W / Alum plate 2lbs / STA weighted 6lbs / Alum 80 / 6lbs added / 60 feet / Turks & Cacios

So are you saying that the only difference between pic 1 and pic 2 is the choice of BCs? There were no other gear changes that took place and more importantly, no other training (formal or through a mentor) that helped result in pic 2?

 

[Adobo]

It isn't an either/or answer... it's both. You should be going for having the weights as close as possible to your lungs while still achieving the desired trim. Trim is more important, but the greater the percentage of ballast is located above (or below) your lungs/wing, the easier that trim is to maintain.

Assuming your center of gravity is right around where your lungs are - which is true for me when diving in a wetsuit but doesn't feel so in a drysuit.

 

[peterbj7]

I like your attitude and despite my conviction that BP/Ws are a far batter design than jacket BCs for diving, I agree that each diver should find his/her own preference, and some people will prefer using a jacket.

Yes, but also a wing with a softback harness rather than a backplate.

 

[Mayor]

So are you saying that the only difference between pic 1 and pic 2 is the choice of BCs? There were no other gear changes that took place and more importantly, no other training (formal or through a mentor) that helped result in pic 2?

Of course the pictures show other gear changes but the main one was the BP/W. I was just showing you the difference between a BP/W vs RI. All that extra fluff has to cause issues with trim.

This diver spent a ton of time working to get Pic #1 to look like Pic#2 but could not. I'm sure he would have gone through his life not knowing that there was a better way till he bumped into cave diver.

 

[peterbj7]

That may be the main gear change, but his whole attitude in the water is different. Look at the angles of his upper and lower legs. If he kept his legs that straight without a backplate his attitude would be different. Also, are both pictures of a stable position that he held for say 10 seconds minimum? And in the "backplate" picture he appears to be in clear water, whereas in the other he is near the bottom apparently looking at something.

 

[Adobo]

Of course the pictures show other gear changes but the main one was the BP/W. I was just showing you the difference between a BP/W vs RI. All that extra fluff has to cause issues with trim.

This diver spent a ton of time working to get Pic #1 to look like Pic#2 but could not. I'm sure he would have gone through his life not knowing that there was a better way till he bumped into cave diver.

I see at least two other gear changes that IMHO are not insignificant - tank is different and fins are different. Not to mention whatever the cave diver taught you in terms of how to distribute your weight, how to position your body, etc.

My point is, one doesn't go from back inflate to backplate and end up with pic1 to pic2 right away. The process is more involved than that. And in fact, at this point, even you were again using a back inflate, you could pick the right equipment (tanks, fins, etc) to weight yourself in a fashion that you could achieve the same trim.

 

[Mayor]

That may be the main gear change, but his whole attitude in the water is different. Look at the angles of his upper and lower legs. If he kept his legs that straight without a backplate his attitude would be different. Also, are both pictures of a stable position that he held for say 10 seconds minimum? And in the "backplate" picture he appears to be in clear water, whereas in the other he is near the bottom apparently looking at something.

He might be looking at his SPG and is stopped in the water now that you mention it. How about this one. I'm not saying the BP/W is for everyone but it does help.

 

[Mayor]

I see at least two other gear changes that IMHO are not insignificant - tank is different and fins are different. Not to mention whatever the cave diver taught you in terms of how to distribute your weight, how to position your body, etc.

My point is, one doesn't go from back inflate to backplate and end up with pic1 to pic2 right away. The process is more involved than that. And in fact, at this point, even you were again using a back inflate, you could pick the right equipment (tanks, fins, etc) to weight yourself in a fashion that you could achieve the same trim.

Picture #2 could have an HP130 on his back and look the same. Maybe a puff of air in the wing at the start of the dive. The tank does have some effect but in this case it is a non issue. The OMS slipstreams are neutral in the water and I would guess the Aqua Lung blades are positive. They are not negative for sure.

Yes training and time in the water has a lot to do with it but can you trim out a jacket style BCD as easy as a BP/W?