Question Please judge my Sidemount Frankenstein Rig and point out potential issues

[jstotz]

Hi, I originally trained for sidemount in an old Hollis SMS100. I'm getting ready for a trip to Puerto Rico that will include lots of caving, a shallow ocean dive, and hopefully a cave sump dive.

My Hollis SMS100 dual bladder is enormous and bulky($$ in baggage fees already burdened with vertical caving gear).
I was previously given a mostly complete Dive Rite Trans Pac and thought I'd rig it up for a lightweight travel sidemount/hybrid BCD.

Components:
- Dive Rite Transpac II (missing back pad but ordered compatible replacement)
- Light Monkey 28 lb single wing, 360 donut style (gusseted upper section with bungee to move lift rearward)
- Loop bungee kit (off of sms100)
- semi-rigid back plate (to prevent wing taco)

Concerns:
1. Will this provide enough lift for 2 alu 80's? (I'll wear 0-3mm wetsuit, so I should need very little weighting.)

2. There is no butt plate. Will I be able to hold gear in a rearmost hip D-ring and clip each lower cylinder attachement to the slightly forward hip rings?

3. Because I have little to no back pad I have to face the stainless bolts outward(wingnut exposed). Also the squared carriage bolts are just spinning in the round grommets so I think I'll get some regular hexhead stainless bolts and tighten with a wrench unless there's another solution?



Why:
The motivation for this custom project is that I'm a poor boy and have lots of cheap, old crap off FB marketplace. So if I can slap toghether a lightweight sidemount rig for free with gear I already have as opposed to $700+, then that would be a win.

 

[jstotz]

Concerning the spinning stainless carriage bolt issue... has anyone ever tried using a dremel to give the carriage head a slot for a big flathead screwdriver?

 

[rongoodman]

Too much junk for a pair of Al80s. I'd look for a used XDeep Classic or similar. (At one time a sidemount Frankenstein rig was some webbing and an MSR Dromedary bag.)

 

[grantmac]

You can get a far better bladder for $80:

DECO Sidemount Bladder Only 22#

Bladder Only Bases already installed No Valves, hoses, inflator or OPV

www.diveequipmentco.com

Then put together a harness very easily with plates from AliExpress or just diy.

 

[jstotz]

You can get a far better bladder for $80:

DECO Sidemount Bladder Only 22#

Bladder Only Bases already installed No Valves, hoses, inflator or OPV

www.diveequipmentco.com

Then put together a harness very easily with plates from AliExpress or just diy.

Interesting unique design. It's not immediately obvious to me how that bladder integrates in with a harness, or even what orientation it's worn in relation to the body...

 

[Umuntu]

Interesting unique design. It's not immediately obvious to me how that bladder integrates in with a harness, or even what orientation it's worn in relation to the body...

One of the earliest designs …. See below for answer to your question.

How To Rig A Deco Sidemount Harness And Wing Perfectly!

How to assemble a Deco Sidemount harness that allows permanent & reliable attachment of the wing. This step-by-step guide shows you how!

scubatechphilippines.com

It’s actually not that different to a Razor or XDeep Stealth Classic.

 

[rjack321]

Hi, I originally trained for sidemount in an old Hollis SMS100. I'm getting ready for a trip to Puerto Rico that will include lots of caving, a shallow ocean dive, and hopefully a cave sump dive.

My Hollis SMS100 dual bladder is enormous and bulky($$ in baggage fees already burdened with vertical caving gear).
I was previously given a mostly complete Dive Rite Trans Pac and thought I'd rig it up for a lightweight travel sidemount/hybrid BCD.

Components:
- Dive Rite Transpac II (missing back pad but ordered compatible replacement)
- Light Monkey 28 lb single wing, 360 donut style (gusseted upper section with bungee to move lift rearward)
- Loop bungee kit (off of sms100)
- semi-rigid back plate (to prevent wing taco)

Concerns:
1. Will this provide enough lift for 2 alu 80's? (I'll wear 0-3mm wetsuit, so I should need very little weighting.)

2. There is no butt plate. Will I be able to hold gear in a rearmost hip D-ring and clip each lower cylinder attachement to the slightly forward hip rings?

3. Because I have little to no back pad I have to face the stainless bolts outward(wingnut exposed). Also the squared carriage bolts are just spinning in the round grommets so I think I'll get some regular hexhead stainless bolts and tighten with a wrench unless there's another solution?



Why:
The motivation for this custom project is that I'm a poor boy and have lots of cheap, old crap off FB marketplace. So if I can slap toghether a lightweight sidemount rig for free with gear I already have as opposed to $700+, then that would be a win.

Are you cave trained at all? Since you can't even deduce the correct amount of lift you need for 2x al80s in a 3mm suit - it does not sound like you are trained for what you're planning.

 

[jstotz]

Are you cave trained at all? Since you can't even deduce the correct amount of lift you need for 2x al80s in a 3mm suit - it does not sound like you are trained for what you're planning.

I admit I have never worn a 3mm suit before, though I find that an uninspiring argument.

People should not attempt dives beyond their training limits. To do otherwise invites large amounts of risk.

 

[rjack321]

I admit I have never worn a 3mm suit before, though I find that an uninspiring argument.

People should not attempt dives beyond their training limits. To do otherwise invites large amounts of risk.

Will only say that trying to learn to sump diving, in a new place, with all new gear, all on the cheap, with your current cave assessment skills is probably a bad idea.

J

Question Post in thread 'Monroe County, MI - Great Sulfur Spring'

Feb 10, 2025

What was damaged the most? Drysuit stench that won't go away?

How much actual physical damage to gear is yet to be assessed. I suspect, and hope, more stench than actual damage. The water itself didn't smell particularly bad to me today--unlike during my first visit and scope a few weeks ago--so perhaps my sinus wasn't as clear today.

What really surprised me--and not in a good way-- is that the white-floored, shallow 1ft deep area surrounding the deeper spring hole does not have a solid floor as I previously thought. I took one step out with 100 lbs of steel back plate and twin...

• jstotz

• 

 

[jstotz]

Will only say that trying to learn to sump diving, in a new place, with all new gear, all on the cheap, with your current cave assessment skills is probably a bad idea.

J

Question Post in thread 'Monroe County, MI - Great Sulfur Spring'

Feb 10, 2025

What was damaged the most? Drysuit stench that won't go away?

How much actual physical damage to gear is yet to be assessed. I suspect, and hope, more stench than actual damage. The water itself didn't smell particularly bad to me today--unlike during my first visit and scope a few weeks ago--so perhaps my sinus wasn't as clear today.

What really surprised me--and not in a good way-- is that the white-floored, shallow 1ft deep area surrounding the deeper spring hole does not have a solid floor as I previously thought. I took one step out with 100 lbs of steel back plate and twin...

• jstotz

• 

I ain't afraid to post my own mishaps. I won't claim that there's little or no risk to what I want to attempt in the near future, but I do understand the risks, I have had a good deal of training, and am prepared for the consequences. I'll probably eventually end up like Sheck Exley or Wes Skiles, but in the meantime I'll make my best Mike Young imitation.

I see you're vastly more experienced a diver than I am. If it makes you feel better I am confident that this is a very shallow 0-20ft sump. Most of the complication will be getting the gear down 3 vertical pitches to it.