Balanced Rig

[in too deep]

I can balance in fresh water doubl 80's rather well, however, switching to Faber 95's is really challenging.
- double alum 80's with a ss bp, can light, no lead, using a 50lb wing, with or without stage and deco bottles in a wetsuit or drysuit - no problem.
- switching to 95's with alum bp, can light, no lead, using a 50lb wing with a drysuit i have to inflate the wing completely plus a little in the drysuit to be positive at the surface.
Is it worth getting rid of the 95's and getting alum 100's.

 

[ams511]

Here is a link to a chart of tank specifications from Tech Dive Limited. Unless I am missing something, going from 85s to 95s will decrease your buoyancy by about 4 lbs. Switching from a SS to an AL backplate should increase your buoyancy by 4 lbs, so theoretically it should balance out. My guess (and it really is a guess) is that the larger diameter of the 95s is not allowing your wing to expand completely. It should not take 50lbs + of lift to float that rig at the surface. My other guess would be the positioning of the wing. Remember for a wing to have lift it must displace water. If the wing is set high and the tanks low then less of the wing is in contact with the water so you will need to inflate it more. It is an interesting question, I am looking forward to seeing the answers.

 

[Insta-Gator]

The Faber 108 would give you more 'end of dive' buoyancy than the 95.

 

[in too deep]

Here is a link to a chart of tank specifications from Tech Dive Limited. Unless I am missing something, going from 85s to 95s will decrease your buoyancy by about 4 lbs. Switching from a SS to an AL backplate should increase your buoyancy by 4 lbs, so theoretically it should balance out. My guess (and it really is a guess) is that the larger diameter of the 95s is not allowing your wing to expand completely. It should not take 50lbs + of lift to float that rig at the surface. My other guess would be the positioning of the wing. Remember for a wing to have lift it must displace water. If the wing is set high and the tanks low then less of the wing is in contact with the water so you will need to inflate it more. It is an interesting question, I am looking forward to seeing the answers.

ams511, i did forget to mention the 80's are alum, and i realize i put 85's in the second sentence, since edited this may change your reply....

 

[danvolker]

I can balance in fresh water doubl 80's rather well, however, switching to Faber 95's is really challenging.
- double alum 80's with a ss bp, can light, no lead, using a 50lb wing, with or without stage and deco bottles in a wetsuit or drysuit - no problem.
- switching to 95's with alum bp, can light, no lead, using a 50lb wing with a drysuit i have to inflate the wing completely plus a little in the drysuit to be positive at the surface.
Is it worth getting rid of the 95's and getting alum 100's.

I think you have answered your own question.....You should be able to swim the doubles up to the surface without needing the wing....dual 80's make this easy....the dual 95's sound like a suicide rig for you, If you don't get enough air with the dual 80's, consider an 80 cu ft stage bottle clipped on to the left side, or just using shorter bottom times...or using a scoOter to DRASTICALLY LOWER air consumption from much lower work rate.

Going with bigger and bigger tanks continues to complicate the dive with ever larger bouyancy and increased drag problems.

 

[PfcAJ]

That's very odd that you can't get positive with a 55lb wing in that configuration. Your wing should be more than enough to float 95s, the plate, and light without you even in it (and if you are in a drysuit, you float, too). My old 55lb wing was enough to float cave filled 104s and a steel plate.

I've got a hunch that you're in fact positive, but the tanks are too high on your back, so you can't get your face out of the water. Try dropping the backplate down your back a few inches by loosening the shoulders and tightening the crotch strap and see what happens.

 

[ams511]

ams511, i did forget to mention the 80's are alum, and i realize i put 85's in the second sentence, since edited this may change your reply....

Well going from AL-80 to a Faber LP-95 you are gaining about 14 lbs according to the chart you lose 4 switching to a AL backplate so your net is a 10lb increase.

 

[halocline]

I can balance in fresh water doubl 80's rather well, however, switching to Faber 95's is really challenging.
- double alum 80's with a ss bp, can light, no lead, using a 50lb wing, with or without stage and deco bottles in a wetsuit or drysuit - no problem.
- switching to 95's with alum bp, can light, no lead, using a 50lb wing with a drysuit i have to inflate the wing completely plus a little in the drysuit to be positive at the surface.
Is it worth getting rid of the 95's and getting alum 100's.

Nothing is worth AL100s to me.

Something is not right if you are in a drysuit, no lead, and having a big problem staying positive at the surface. I can't imagine full double 95s with bands, manifold and a can light being much more than 20 lbs negative, probably less. I think you should figure out that before investing in new tanks.

HP100s, specifically faber FX100s, are fairly close to neutral empty, so maybe they're a better option for you than 95s. Double steel tanks with a wetsuit are frowned upon by the old school crowd because of the lack of redundant buoyancy. Hence the dual bladder wings with an extra inflator hose. Personally I would opt for a lift bag instead; one inflator hose is plenty for me.

I like double AL80s and I don't know why you want to change from them unless you really need more gas. To me that means a deep difficult advanced dive, and usually people don't do that sort of diving without a very good understanding of their rigs and the buoyancy issues.

 

[NAM001]

my imidiate responce would be to say no way. i will assume i am missing something so pls tell me how teh lp95's are gaining about 14 lb. are you talking scale weight or bouyancy???

Well going from AL-80 to a Faber LP-95 you are gaining about 14 lbs according to the chart you lose 4 switching to a AL backplate so your net is a 10lb increase.

---------- Post Merged at 12:55 PM ---------- Previous Post was at 12:52 PM ----------

i can not explain this either. one thought is you wing a doubles wing or a wing that is listed for use with both single or doubles. i had a dive rite wing that is like that.

I can balance in fresh water doubl 80's rather well, however, switching to Faber 95's is really challenging.
- double alum 80's with a ss bp, can light, no lead, using a 50lb wing, with or without stage and deco bottles in a wetsuit or drysuit - no problem.
- switching to 95's with alum bp, can light, no lead, using a 50lb wing with a drysuit i have to inflate the wing completely plus a little in the drysuit to be positive at the surface.
Is it worth getting rid of the 95's and getting alum 100's.

 

[ams511]

my imidiate responce would be to say no way. i will assume i am missing something so pls tell me how teh lp95's are gaining about 14 lb. are you talking scale weight or bouyancy???

Your right that doesn't make much sense, let me try again. Faber LP 95s are -8.325 a Luxfer 80 is -1.4 so the 95 is approximately 7 lbs less buoyant than the 80 (based on full tanks). Being the OP is diving doubles we multiply this by 2 so he is 14 less buoyant. The OP also mentioned that on the 80s he uses a SS plate (5-6 lbs) while using 95s he uses an AL plate (about 2 lbs), which is 4lbs more buoyant. So -14 + 4 = -10. His rig is 10 lbs less buoyant with the 95s than the 80s.

---------- Post Merged at 11:08 AM ---------- Previous Post was at 11:02 AM ----------

Something is not right if you are in a drysuit, no lead, and having a big problem staying positive at the surface. I can't imagine full double 95s with bands, manifold and a can light being much more than 20 lbs negative, probably less. I think you should figure out that before investing in new tanks.

Tanks 8.325 x 2 = ~ 17
Back Plate = 2
Regs = 5
Can Light = 3
Bands/manf = 3
Total 30 (I may be a pound or two heavy)