Question about “balanced rigs” and having all ballast unditchable

[MichaelMc]

Philosophy:
Some lead on body for any entangles, incremental ditchable, not too thick suit. Shore entry capable. Love to go 2x AL40 for compact gas redundancy or volume, but single tank.

Diver: +5 lb.
Suit: +14 lb. wet - robustness, low drag, easy, FJ seals tight, ventable, mix and match
Belt 4 lb.: some on body, ditchable, metal buckle
BP/W: - flexibility, robustness
- AL: flexibility for trim and ditch
- 4 lb.: high on plate to maximize on body, trim, non-ditch for compactness (could go with ditchable)
- 4 lb.: integrated ditchable, more incremental than all on belt.
- 30 lb. lift: exceeds suit + air. less is unnecessarily cutting it fine. 40 lb. good also.
- SS 15' neutral on low air.

BC fail buoyancy:
Bottom: ~-17 lb less ditched (7 lb. gas, 8 lb. less lift past SS level(?))
Surface: -3, +1, +3, +5 lb. (-7 gas, +4 lb. above SS, and +4, +6, +8 lead)(+ DSMB)

The ditchable lead should cover redundant buoyancy. But, dual bladder would be a bonus, to not need to do fine bottom ditching. But I can't quickly find a single tank redundant bladder. Justification: It might be ~$150 more, in total cost that is not big.

Tank: LP85 - capacity for 30-60', pushing it for 100', neutral ish buoyancy, more capacity. Side mount...
Pony: AL19: for random insta buddies.
Stage: AL40: rare 100' dive for total volume and redundancy.

Safety: DSMB 3'/6 lb. (easy size to learn), 100'+ spool, whistle (close use), mirror (far use), EMT shears (versatile), ceramic cutter (for after you drop the shears, no rust), 1-2 lights, small slate.

This is largely my light suit configuration.

 

[Dan_P]

Let’s do a scenario and everyone pick their recommended configuration for a basic diver. I’ll set a couple of basic parameters so we don’t get into the weeds arguing about semantics. First the diver we are ADVISING is a newly certified diver, decent health and is planning on ocean diving where water temps for the good dive season ranges between 60F and mid-70s. He is going to want single tank diving max depth to 100 FSW. The vast majority of his dives will be in the 30’-60’ range.
GEAR
He can use AL tanks, Steel, pony bottle (he will NOT be intentionally solo diving, but may get random instabuddy). For buoyancy you can choose a jacket, back inflate, BP/w. The plate can be either steel or AL.

He needs to have redundant buoyancy. It can be what ever you like, double bladder, wetsuit, dry suit, lift bag or SMB, but he has to be able to rest at the surface passively. You also have to describe how they are ballasted. He needs to be able to get from 100 fsw with a disabled BCD. Being the core topic more detail is encouraged. If you have an overarching philosophy, state it. For completeness (this a basic forum), what are the emergency gear you think he should have?

We’ll skip the branding as much as possible. Here is the caveat. You need to justify your choice for each pick. You cannot comment on another persons choices until after you post about yours.

(This be what finally kills this Franken-thread or gets it to 80 pages)

Given that the person is also buying or already in possession of the training required for the equipment/diving in play:

I'd advice a drysuit, single-tank BP/W with steel 12L - but I'd be 100% clear with that diver that it's because it scales well so if that diver grows fond of diving and decides to dive through the winter also, or go deeper, or go tech, they'd have a really easy time growing their kit into that utility.

If that diver then decides "nah" and scales down from the recommendation, that's fine, but they're doing so informed of the needs if they develop their diving.

They can then evaluate that benefit towards the cost, and decide if they're interested in maybe growing their diving.
They might not know for sure if they want to do that yet, but they're making that decision for themselves, on an informed basis.

To be certain, if the diver says they're interested in max. 18m diving, I'd have no problem selling them a thick wetsuit.
But I'd make sure they know I wouldn't advice that suit for deeper diving, and it's useless if they decide to become techies one day.

 

[Compressor]

We are not arguing just for the sake of arguing here, are we?

 

[J-Vo]

[QUOTE="...as a drysuit to learn with and simpler than a drysuit at shallow depth, also much less lead required than diving dry...[/QUOTE]

I'm not sure where this idea that dry suites require more lead came from. Maybe in the tropics. I have a 6.5mm farmer john. It takes something like 28 lbs (haven't used it in years) to get me under in fresh water. I dove dry in 40F water a few weeks ago and used 16lbs with no backplate, AL80, and was perfectly warm. I suppose in the arctic I would need more insulation and lead, but I would also need a thicker wet suit.

 

[Storker]

I'd advice a drysuit, single-tank BP/W with steel 12L

200, 232 or 300 bar? There's a slight difference

 

[Dan_P]

You mean if they want to make a twinset out of it?

EDIT:
232 Bar

 

[Storker]

You mean if they want to make a twinset out of it?

No. I mean that a 12x200 is on the low side (not much more gas than an Al80) and a 12x232 might just as well be changed for a 15x200 or a 10x300 (and with the 10x300 the diver could shave off a couple of kilos from their belt) , so I was guessing you were thinking of a 300 which gives the diver some 3600 nominal surface liters of gas. Which would give them a bit of a margin, but isn't very well suited for people below average height.

 

[Dan_P]

No. I mean that a 12x200 is on the low side (not much more gas than an Al80) and a 12x232 might just as well be changed for a 15x200 or a 10x300 (and with the 10x300 the diver could shave off a couple of kilos from their belt) , so I was guessing you were thinking of a 300 which gives the diver some 3600 nominal surface liters of gas. Which would give them a bit of a margin, but isn't very well suited for people below average height.

You're right to point to this - but I don't think it's something we should split hairs over.

I think a fair share of the consideration has to take into account what's normal/available in terms of tanks, in one's region.
Personally, I usually handle steel 12L 232s or alu 80's, but it's really not about the tank preference or availability to me.
300's are usually heavier, can't necessarily be filled to 300 in all places and I can't utilize the full theoretical gas volume.
But if that's what's available, I'll dive them and enjoy my dive.

Personally, I "like" the 12L 232, it's readily available in my backyard and I think it's a reasonable size in terms of volume and weight, for a twinset. That's it.

But I never fly out with them anyway, and always rent what's suitable/available when travelling, so I'm fine agreeing that it's hardly written in stone

 

[Storker]

Personally, I usually handle steel 12L 232s or alu 80's, but it's really not about the tank preference or availability to me.
300's are usually heavier, can't necessarily be filled to 300 in all places and I can't utilize the full theoretical gas volum, but it's really not about the tank preference or availability to me.
300's are usually heavier, can't necessarily be filled to 300 in all places

So far, I've never had an issue with getting a 300 bar fill. Admittedly, if I don't top up the tank after it's cooled off, I have a short fill, but I can live with that. And since a 10x300 weighs more or less the same as a 12x232 and has the same real capacity (nominally about 10% more, but compressibility shaves ~10% off nominal capacity at 300 bar), I can carry 2kg less on my belt. So all my tanks are 10x300. If I were PP blending, I'd probably reconsider that choice, but I'm not.

I can't utilize the full theoretical gas volume

Please elaborate

 

[Dan_P]

I simply meant this

(nominally about 10% more, but compressibility shaves ~10% off nominal capacity at 300 bar)

I'd end up with slightly more usable gas on a 12L 232 than a 10L 300, but not a lot.