Weighting options with BP/W setup

[Brewone0to]

Well, for me i weight myself as neutral.
It is not needed as part of my rig.
It is a preference of mine for no-mount situations.

There are many options for tanks with varying boyancy characteristics.(see link below)
Scuba Cylinder Specification Chart from Huron Scuba, Ann Arbor Michigan

Also there are several plate choices.
If you still need more weight there are weights designed to go into the depression of the plate.
This will spread the weight across your torso being least obtrusive to trim. (like the plate does)

The most difficult item for me had to be fins, finding the right ones with
the right boyancy was the battle for easily having good trim out.
Subtle differences here make dramatic effects in trim because fins are as far from center as one can get.
Good luck working out your rig, have fun and dive safely.

 

[Ricky B]

trim weights on your cam bands

I am not entirely clear about the suggestion to put trim weights on the cam bands. The cam bands are what hold the tank to the backplate, correct? So does one thread a cam band through some sort of pocket and have the pocket affixed to the side of the tank like some kind of wart? You use them in pairs, putting one on each side of the tank, so that the weight is evenly balanced from side to side?

It seems to me that weights on the cam bands would be non-ditchable. Is that right?

---------- Post added March 13th, 2014 at 07:39 PM ----------

Also there are several plate choices.
If you still need more weight there are weights designed to go into the depression of the plate.

Like this? XS Scuba V Weight Pouch discounts on sale XS Scuba

Or like this?: V-Weights

Or are you referring to something else altogether?

 

[doctormike]

I am not entirely clear about the suggestion to put trim weights on the cam bands. The cam bands are what hold the tank to the backplate, correct? So does one thread a cam band through some sort of pocket and have the pocket affixed to the side of the tank like some kind of wart? You use them in pairs, putting one on each side of the tank, so that the weight is evenly balanced from side to side?

It seems to me that weights on the cam bands would be non-ditchable. Is that right?

You are correct on all counts! They are little pockets that hold 4-5 lbs max on the outside of the cam band. They don't get in the way, since the "warts" are tucked in close to the backplate.

But remember, you don't need to ditch ALL of your weight. For example, the backplate is non-ditchable ballast. If you try to make all of your weight ditchable, then whatever you need is going to be in one place (like a weight belt or pockets). Much more comfortable to have it distributed, in my experience.

 

[Ricky B]

Let's say the steel backplate is 6 lbs. and a steel PST LP-80 is negative 7 lbs. when full. If the bladder in the wing is empty, wouldn't the rig be 13 lbs (plus the weight of the rig), or is there something that would create buoyancy that I'm not thinking of?

And if the diver needed, say, 27 lbs. of lead, would the 13 lbs for the rig and 14 lbs of lead on the body be balanced? But if the diver needed 27 lbs to submerge at the beginning of the dive, wouldn't the diver be positively buoyant if he doffed his rig and wouldn't the rig be negatively buoyant?



---------- Post added March 13th, 2014 at 07:51 PM ----------

But remember, you don't need to ditch ALL of your weight.

Just enough so you can swim to the surface without any lift from a buoyancy device (e.g., in case of wing failure)?

 

[gcarter]

Let's say the steel backplate is 6 lbs. and a steel PST LP-80 is negative 7 lbs. when full. If the bladder in the wing is empty, wouldn't the rig be 13 lbs (plus the weight of the rig), or is there something that would create buoyancy that I'm not thinking of?

And if the diver needed, say, 27 lbs. of lead, would the 13 lbs for the rig and 14 lbs of lead on the body be balanced? But if the diver needed 27 lbs to submerge at the beginning of the dive, wouldn't the diver be positively buoyant if he doffed his rig and wouldn't the rig be negatively buoyant?



---------- Post added March 13th, 2014 at 07:51 PM ----------



Just enough so you can swim to the surface without any lift from a buoyancy device (e.g., in case of wing failure)?

Don't forget that part of the lead is to compensate for the air you will use throughout the dive. The equation changes at different points of the dive.

 

[Luis H]

scrapping the redundant buoyancy discussion as its off topic from OP.

i do run a QR buckle on my crotch strap; it (crotch strap) managed to get tangled around the backside of the weight belt during a ditch drill after the belt had cleared the bottom of the plate. needless to say, that rattled me just a bit. maybe when i get up to 1000+ dives it may be easier, but for now ill take intuitive one step ditch rather than two step (QR, then weight belt) and having to think about it.

balanced rig with a pocketed weight belt under the strap seems the best of both worlds for rec diving.

If you attach the front of the crotch strap to the front of weight belt (with just a loop around the weight belt), when you release the weight belt, the front of the crotch strap just drops and the weight belt drops without getting tangled.

This system was used for a long time very successfully (mostly in Europe). I have used it for years and have tested it several time.

I use one inch webbing for my crotch strap with snap buckles at the end to form a loop. The last thing that I attach it the crotch strap around the front of the weight belt (instead of around the front of the tank harness waist strap).

It works well, it is reliable, and it is simple.

 

[Instructor_Tom]

Let's say the steel backplate is 6 lbs. and a steel PST LP-80 is negative 7 lbs. when full. If the bladder in the wing is empty, wouldn't the rig be 13 lbs (plus the weight of the rig), or is there something that would create buoyancy that I'm not thinking of?

And if the diver needed, say, 27 lbs. of lead, would the 13 lbs for the rig and 14 lbs of lead on the body be balanced? But if the diver needed 27 lbs to submerge at the beginning of the dive, wouldn't the diver be positively buoyant if he doffed his rig and wouldn't the rig be negatively buoyant?

Ah and the light goes on...

So this is the very reason that in another thread i stated the point the you need to figure out what your total weight requirement is and size your wing to float that weight should you need to ditch your setup, otherwise you will need to buy a new setup the first time you take you BP/wing or BCD off at the surface and let go as it will sink to Davy Jones Locker.

Because i dive dry a lot and need about 28lbs + -11lbs for my LP108 (39lbs) i dive a hollis LX 44lb wing ( add a light, spool, or misc) and you can quickly see why i use a higher lift wing than many will say is good for single tank diving. Half my weight is none ditch-able on the cam straps and half is on the waist strap with pockets that hook on to the backplate.

Hope this helps.

T.



Sent from my iPad using Tapatalk HD

 

[doctormike]

Let's say the steel backplate is 6 lbs. and a steel PST LP-80 is negative 7 lbs. when full. If the bladder in the wing is empty, wouldn't the rig be 13 lbs (plus the weight of the rig), or is there something that would create buoyancy that I'm not thinking of?

Your exposure suit

But remember, you don't need to ditch ALL of your weight.

Just enough so you can swim to the surface without any lift from a buoyancy device (e.g., in case of wing failure)?

Right. And ideally, you should be weighted in such a way that you are able to swim to the surface without ditching any weight (Andy has a good page about the "balanced rig" concept). Ditching weight is really for medical or other emergencies at the surface. If you ditch weight underwater, you may not be able to do a controlled ascent (or any required deco stops).

 

[Ricky B]

Your exposure suit

True enough, but what I had that in mind (but neglected to state) was whether I was missing anything else on the rig that would affect buoyancy. Based on your reply, it appears the answer is no (unless air is trapped in the wing, of course).

---------- Post added March 13th, 2014 at 08:50 PM ----------

Right. And ideally, you should be weighted in such a way that you are able to swim to the surface without ditching any weight (Andy has a good page about the "balanced rig" concept). Ditching weight is really for medical or other emergencies at the surface. If you ditch weight underwater, you may not be able to do a controlled ascent (or any required deco stops).

And now the light really goes on.

For some reason, I had this notion that the weight needed to be released only under water and did not consider emergencies at the surface (which of course would only happen to the other guy).

Being used to cheap rental equipment, where the only weighting is a canvas belt with lead weights that slide around, my view of ditching weight was that you unbuckle your belt and drop it--an all-or-nothing proposition. Since I never had trouble swimming to the safety stop with no air in my BC, even when over-weighted, I never considered having to ditch my weight belt as a likely contingency.

 

[doctormike]

True enough, but what I had that in mind (but neglected to state) was whether I was missing anything else on the rig that would affect buoyancy. Based on your reply, it appears the answer is no (unless air is trapped in the wing, of course).

Yeah, if you have a classic BP/W with just the plate, the wing, the webbing and whatever holds it to the tank (bolts for doubles, cam bands or single tank adapter for singles), then nothing is going to be positive. Some people put padding on their webbing, which is slightly positive...