What are the implications of being overweighted with a backplate?

[Michael.52]

I've just got back from my second dive with my new gear configuration, and would be glad to hear your advice, opinions, feedback, and anything else useful that is relevant or related...
Background:
I got a 25lbs lift bladder, with a SS 5.5lbs plate. I weigh 60kg, and compared to divers around me, I usually find the water a bit colder than them.
Most my diving is as an assistant instructor in the dive-season in the Red sea - quite stable water temperatures. I also dive with friends from college a bit in the Mediterranean - which has a vaster temperature range.
I Own a 3mm and 7mm full wetsuit, and also a 3mm chicken vest with hood, which gives me enough options to switch around etc. to have a comfortable temperature in whichever season I am diving (except winter Mediterranean).

Yesterday's dive: Med sea, 3mm suit, 4 pounds on belt, 12L aluminum tank.
I Knew in advanced I would be over weight, but I intended to test my gear with the extra weight since next week I'll be in the Red Sea where if I am at work, I might have to use a weight belt when working and demonstrating drills to other divers.
I also noticed my inflator controls were relatively short to my previous BC. They only just reach about an inch ABOVE my nipple's height.

Today's dive: Med sea, 3mm suit, no belt, 7L aluminum tank.
On the surface I did the weight check (empty BC, full lungs, exhale)...with full lungs I sunk at a moderate pace.
After the ascent at the end of the dive, I chose to orally inflate my BC. Since one's mouth and lungs aren't a power inflator, the bladder wouldn't achieve it's best capacity, but was inflated enough to give me positive buoyancy, but when feeling it with my hand, it was still quite soft...I wonder what would happen if I would have to use it to support a distressed diver in rougher conditions...

Some of the points to discuss:
Did I purchase the wrong backplate or too small a bladder?
How critical is it being over weighted, considering that most the weight is near my centre of buoyancy, instead of on my hips?
Is there a reason I am unaware of that they make such short corrugated hoses for certain inflators?

 

[Hatul]

You may need to change to an aluminum or plastic plate, if you want to keep some ditchable wt and not be overweighted.

 

[DevonDiver]

Is there a reason I am unaware of that they make such short corrugated hoses for certain inflators?

After much painstaking research, a secret industry-insider team calculated that very few divers inflated their LPI using their nipple...

On a serious note; ascertain desired functionality:

Can it be orally inflated? yes/no
Can it be power inflated? yes/no
Can it be raised upwards for dumping? yes/no

If all the above are fulfilled, what benefit is there in having it dangle around your mid-section?

 

[Wookie]

In the States, you can get any length corrugated hose you want. I know that doesn't really help, but I get an extra long one so my inflater falls right. As for the buoyancy, I find I am in trim with no weight on my hips. I wear a ss backplate and 12l steel and no lead with a 3 mil. I am about 2# heavy, which I figure I can swim up in the event of a complete failure of my wing. I wear a 32# wing for normal diving. With an aluminum 12l cylinder, I wear 12# of lead with the same configuration, but have to work to keep in trim.

As far as helping a distressed diver, you can only plan for so many failures at a time. If you had a complete failure of buoyancy, use the distressed divers. If they have a complete failure of buoyancy, use yours. I don't plan for multiple failures at the same time, scuba gear is fairly reliable, and we'd all be carrying 2 of everything if it weren't.

 

[Michael.52]

@DevonDiver:
Can it be easily reached without getting into cramp or out of trim? yes/no
...in my case, I think I will get a longer one, without impairing the ability to dump air clearly.

@Hatul:
&
@Wookie:
I just made a chart of combinations of insulation I could wear, how much weight I estimated each would require, and if the amount would be more efficient to acquire with a SS or Aluminum plate. The score was 2v2.
This is pointing me towards a conclusion that require more consulting:
Is it smarter to be unconventional and stay with the SS, and when I rarely dive with little/no exposure gear, add some sort of positive buoyancy such as a low-density solid I could stow under my back padding (for got to mention, that I also got padding in the configuration, but that's only slightly positive)?
Or is it smarter to switch to an Aluminum plate, and when diving with the thicker wetsuits, add weight to my belt (which will defy half the point of having a backplate weight system), or use an STA for that season? (since the Hollis S 25 doesn't require an STA)

 

[PfcAJ]

If your wing can float your gear (full tank) without you in it, its good.

If you can swim up from depth (suit compressed) with an empty wing and full tank, its good.

If you can hold a stop at 3m with an empty tank, its good.

If you can orally inflate, pinch your nose to clear your ears while holding the inflater, and hold your inflater and reach your drysuit valve (if you have one), its good.

If you cannot do one of the above things, something is wrong and needs fixing. It is not good.

 

[eelnoraa]

I highly doubt with 7mm wetsuit, a SS plate makes you over weighted. So let's worry about the 3mm. Simple test is with nearly empty tank, empty bladder, if you are still sinking at the surface, then you are over weighted.

 

[Hatul]

Michael, Can I ask you what brand of BP/Wing you got? Personally I would not dive with less than 4 lbs of ditchable weight -- that's only 2 lbs on each side. You can get a lighter plate/harness and save the steel plate with harness for your 7 mm wetsuit diving. 25 lb wing should work well with a 3 mm wetsuit. When I dove with BP/Wing I also had two sets: steel and aluminum for California and warm-water diving.

Also can I ask you where in the Med you dive in Israel? Several years ago I was looking in the Caesarea area to dive but never found any dive operator there.

 

[DevonDiver]

@DevonDiver:
Can it be easily reached without getting into cramp or out of trim? yes/no
...in my case, I think I will get a longer one, without impairing the ability to dump air clearly.

Mystified... your head is on top, arms at the sides... shoulders under the head? Standard configuration for a homo-sapien?

I'm trying to picture this conundrum, but admit I'm confused...

At what point can't you reach the LPI??

For dumping.. you are aware that with BP&W.. being horizontal in good trim... you'd be dumping from the rear (butt) valve?

I just made a chart of combinations of insulation I could wear, how much weight I estimated each would require, and if the amount would be more efficient to acquire with a SS or Aluminum plate. The score was 2v2.
This is pointing me towards a conclusion that require more consulting:
Is it smarter to be unconventional and stay with the SS, and when I rarely dive with little/no exposure gear, add some sort of positive buoyancy such as a low-density solid I could stow under my back padding (for got to mention, that I also got padding in the configuration, but that's only slightly positive)?
Or is it smarter to switch to an Aluminum plate, and when diving with the thicker wetsuits, add weight to my belt (which will defy half the point of having a backplate weight system), or use an STA for that season? (since the Hollis S 25 doesn't require an STA)

I think you might be over-thinking this. Do a proper weight check... not the 'float with a breath' taught on OW, but a full confirmation of your weighting needs (maintain neutral buoyant shallow stop with near-empty cylinder and no air in BCD). Plenty enough threads on that process. This will give you decisive feedback in your weighting needs.

I dive a 3mm suit all the time. With BP&W and AL80, I use an AL backplate and 2lbs of lead (trim weight on upper cam band). The wing is Oxycheq 18lb. It could hold a steel (no probs) and the difference would just account for the 2lbs I prefer (less to carry around traveling).

 

[Michael.52]

If your wing can float your gear (full tank) without you in it, its good.
If you can swim up from depth (suit compressed) with an empty wing and full tank, its good.
If you can hold a stop at 3m with an empty tank, its good.
If you can orally inflate, pinch your nose to clear your ears while holding the inflater, and hold your inflater and reach your drysuit valve (if you have one), its good.
If you cannot do one of the above things, something is wrong and needs fixing. It is not good.

Check.
Did that from 6 meters (18ft) today, but that was with a 7L full tank and under optimal conditions, no stress or fatigue.
Check.
Check. (no dry suit)

What is the source of this list? all these tasks can be done even when extremely over-weighted (even the second one)..

I highly doubt with 7mm wetsuit, a SS plate makes you over weighted. So let's worry about the 3mm. Simple test is with nearly empty tank, empty bladder, if you are still sinking at the surface, then you are over weighted.

7mm will be fine with the SS. The dilemma is in regards to the 3mm (as you said), which I can always add weight if I change to an Al plate. The test I performed today was with a full 7L, how much a difference would that make in comparison to an empty 12L?

Michael, Can I ask you what brand of BP/Wing you got? Personally I would not dive with less than 4 lbs of ditchable weight -- that's only 2 lbs on each side. You can get a lighter plate/harness and save the steel plate with harness for your 7 mm wetsuit diving. 25 lb wing should work well with a 3 mm wetsuit. When I dove with BP/Wing I also had two sets: steel and aluminum for California and warm-water diving.

Also can I ask you where in the Med you dive in Israel? Several years ago I was looking in the Caesarea area to dive but never found any dive operator there.

Hollis S series 25lbs, OMS SS plate, Dive Rite basic harness. I am hoping to find the cheapest CORRECT solution, considering that this is expensive gear, especially in Israel.
Do I want an STA and Al plate? do I want an Al plate and belt? do I need to change bladder?
As for diving in Israel, I have little experience in the Med, but I could easily find that out for you.

---------- Post added August 7th, 2013 at 11:01 PM ----------

Mystified... your head is on top, arms at the sides... shoulders under the head? Standard configuration for a homo-sapien?
I'm trying to picture this conundrum, but admit I'm confused...
At what point can't you reach the LPI??
For dumping.. you are aware that with BP&W.. being horizontal in good trim... you'd be dumping from the rear (butt) valve?


I think you might be over-thinking this. Do a proper weight check... not the 'float with a breath' taught on OW, but a full confirmation of your weighting needs (maintain neutral buoyant shallow stop with near-empty cylinder and no air in BCD). Plenty enough threads on that process. This will give you decisive feedback in your weighting needs.

I dive a 3mm suit all the time. With BP&W and AL80, I use an AL backplate and 2lbs of lead (trim weight on upper cam band). The wing is Oxycheq 18lb. It could hold a steel (no probs) and the difference would just account for the 2lbs I prefer (less to carry around traveling).

I can always reach the LPI hose. I have it bungied next to my D ring.
Maybe I am just used to a slightly longer inflator, I will practice more, and if I don't get over it I will consider lengthening it.
I learned that when dumping from the rear it's harder to see how much air comes out, and is less preferable. Or could this be a mind-set that I am bringing from my recreational training and gear, and also just need to adjust?

As for a proper weight check, could you direct me to a thread that has the steps clearly stated? I'll run a search of my own also to compare.

So far my conclusion is veering towards what you said also; I might need to change to an Al backplate, which would go well with 3mm, then if I add my vest on, I can add a belt or an STA, if I am with 7mm I will use the STA and belt, and if I am with the 7mm and vest I will add more weight.
Could you list the methods and places I could add weight on to a BP/W?