Info needed for a recommendation

[BB1]

Hi Tobin,

I have read many posts where you have advised people on BP/W setups.

What exactly do you need in the way of info in addition to my rig details?

Weight needed at safety stop (5m/15') with empty tank to be neutral
or
weight need to be neutral at surface just in my wetsuit (5mm)

I currently use a rented jacket bcd but want to move to a BP/W which I tried and loved.

Thanks!

 

[cool_hardware52]

Hi Tobin,

I have read many posts where you have advised people on BP/W setups.

What exactly do you need in the way of info in addition to my rig details?

Weight needed at safety stop (5m/15') with empty tank to be neutral
or
weight need to be neutral at surface just in my wetsuit (5mm)

I currently use a rented jacket bcd but want to move to a BP/W which I tried and loved.

Thanks!

BB1,

Thanks for asking. I need to know:

Height and weight

Most buoyant exposure suit you plan to use with this gear

Cylinders used.

If you don't know the buoyancy of your suit, (very few do) then I need to know your current configuration when you are using that suit.

For example "With my 5mm wetsuit I use 10 lbs of lead, a XYZ BC and an al 80 cylinder"

Tobin

 

[BB1]

Hi Tobin,

Dived yesterday and had an even worse experience with a new rental XL jacket bcd - More lead needed!

Here are the details for myself and my wife:

Me:

Height: 6'4"
Weight: 240lbs
Wetsuit: 5mm
Cylinders: currently rental AL80 but intend buying a steel tank in the future (232BAR either 100cf or 120cf eg worthington X7-100/X8-119 or a 125cf Faber)

With my 5mm wetsuit I used 24 lbs of lead, an XL OCEANIC BC and an al 80 cylinder
With my 5mm wetsuit I used 21 lbs of lead, with a Hollis AL BP with pad/S25 wing and an elite 2 harness and an al 80 cylinder (it was an equipment tryout day)

My wife:

Height: 5'4"
Weight: 143lbs
Wetsuit: Brand new 5mm
Cylinders: currently rental AL80 but possibly a steel 100cf in the future

With her 5mm wetsuit she used 21 lbs of lead, a medium OCEANIC BC and an al 80 cylinder

Both of us want to reduce the amount of lead we have to wear on a weight belt as much as possible.

If I've missed anything please let me know and thanks in advance for your help and recommendations!

 

[cool_hardware52]

Hi Tobin,

Dived yesterday and had an even worse experience with a new rental XL jacket bcd - More lead needed!

Here are the details for myself and my wife:

Me:

Height: 6'4"
Weight: 240lbs
Wetsuit: 5mm
Cylinders: currently rental AL80 but intend buying a steel tank in the future (232BAR either 100cf or 120cf eg worthington X7-100/X8-119 or a 125cf Faber)

With my 5mm wetsuit I used 24 lbs of lead, an XL OCEANIC BC and an al 80 cylinder

BB1,

In your 5mm suit you had about 26 lbs of thing that don't float, 24 lbs of lead and ~2 lbs of regulator.

Your current BC is very likely ~4 lbs inherently positively and an empty al 80 is + 4 lbs. 26 - 4 (bc) - 4 (empty al 80 ) = 18 lbs. 18 lbs is quite a bit for a 5mm suit. I would *guess* you are slightly over weighted. This may also be due to difficulties in fully venting your current BC.

I'll assume your suit is 14 lbs positive. To be able to compensate for a fully compressed suit you need a wing of greater than 14 lbs lift.

At 6'4" tall you are need a "Long Pattern" back plate. A SS Long Pattern Plate and harness provides about 8 lbs of ballast. Add a reg and full al 80 and your rig will be about - 12 lbs with a full tank, and provide about 6 lbs of ballast with an empty al 80. If your suit is +14 lbs you will need another 6-8 lbs in a belt.

With a steel HP 100 your rig will be about -20 with a full cylinder and about -12 with an empty tank.

That makes a Torus 26 wing a reasonable choice. 26 > 14 (suit buoyancy) and 26 > 20 (max negative of your rig with a full HP 100)

Recap:

Long Pattern SS back plate
Torus 26 Wing
Hogarthian Harness
(cambands and wedge blocks included)

My wife:

Height: 5'4"
Weight: 143lbs
Wetsuit: Brand new 5mm
Cylinders: currently rental AL80 but possibly a steel 100cf in the future

With her 5mm wetsuit she used 21 lbs of lead, a medium OCEANIC BC and an al 80 cylinder

Your wife is using about 23 lbs of total ballast, 21 lead and 2 for the reg. Her current BC is likely ~+4 lbs an an empty al 80 is +4. 23 - 8 = 15 for here 5mm suit.

Here again 15 lbs for a 5mm suit is a bit much, I'd guess she may be slightly over weighted. I'll assume her suit is ~+12 lbs.

At 5'4" tall your wife can use a medium plate.

A medium plate and harness provides about 6 lbs of ballast, her reg 2, and a full al 80 another 2 lbs. Her rig with a full al 80 will be about -10 lbs. and will provide about 4 lbs of ballast with an empty al 80. If her suit is +12 she will need about 6-8 lbs on a belt.

With a HP 100 your wife's rig will be about - 18 lbs with a full tank and it will provide about 10 lbs of ballast with an empty hp 100. That leaves ~2 lbs on a belt.

She can use a LCD 20 or a Torus 26 wing. The 26 would provide enough "spare" lift to accommodate a heavier wetsuit (7mm) It's not uncommon for divers to seek more insulation once their dive times becomes longer with larger cylinders and improved comfort in the water.

Recap:

Medium SS Plate
Torus 26 Wing
Hogarthian Harness
(cambands and wedge blocks included)

Let me know if you have any questions

Tobin

 

[BB1]

Hi Tobin,

Thank you very much for your advice on a suitable setup for us both.

I was definitely slightly negative at the end of my dives last weekend, with all air vented as I ascended I had to swim up each time. Not excessive effort but definitely negative. As I've lost a bunch of weight my wet suit is a little slack around my belly and this may be trapping air as well as its a semi-dry suit. I felt some bubble movement on 1 of the dives.

Thanks for your thorough explanation - it really helps my understanding of whats involved.

How much does the recommendation change if there is a twins rig in my future and how do I deal with redundant buoyancy if I only dive wet? Its to warm here for dry suits!

Many thanks and a PM on its way with an extra question.

 

[cool_hardware52]

How much does the recommendation change if there is a twins rig in my future and how do I deal with redundant buoyancy if I only dive wet? Its to warm here for dry suits!

You can use the same plate and harness for doubles (twins) but you will need a different wing.

Doubles + wetsuit? Consider al 80's. These buoyant cylinders will almost certainly require ballast that can carried in a ditchable manner.

Tobin

 

[BB1]

Hi Tobin,

Thanks again for the advice.

I have a chance to buy 2 Faber 125cf tanks at a very resonable price and wonder if the Taurus 26 would still be enough wing for me. My rough calculations make the rig weight then -22. Would you advise sticking with the Taurus 26 or moving up to the LCD 30 or Taurus 35?

Thanks once again!

 

[cool_hardware52]

Hi Tobin,

Thanks again for the advice.

I have a chance to buy 2 Faber 125cf tanks at a very resonable price and wonder if the Taurus 26 would still be enough wing for me. My rough calculations make the rig weight then -22. Would you advise sticking with the Taurus 26 or moving up to the LCD 30 or Taurus 35?

Thanks once again!

If your new cylinders are neutral when empty then your rig will be about -22 with a full tank (125 cu ft air or nitrox is about 10 lbs.)

Your rig will provide about 12 lbs of ballast with an empty cylinder.

If your suit is actually +14 lbs (an assumption of mine) then your OK, not over weighted.

A 26 lbs wing will float a rig that's -22 lbs.

Tobin

 

[BB1]

Wow, quick response as always.

Faber cylinder details are: buoyancy empty -2.2 buoyancy full -11.6

That seems awful close to the capacity of the T26 wing??

 

[cool_hardware52]

Wow, quick response as always.

Faber cylinder details are: buoyancy empty -2.2 buoyancy full -11.6

That seems awful close to the capacity of the T26 wing??

As long as the wing lift exceeds the max negative for the rig by a couple lbs it won't sink.

If you are properly weighted the 26 is fine. If you anticipate more buoyant exposure suits in the future the 30 is a reasonable choice too.

Tobin