Assembling first doubles rig: Looking for a starting point

[Rainer]

I just got back from a week in Roatan. Water was 79F. We dived dry. Was comfortable.

That said, in even warmer water, I might not want to bother with the drysuit. In any case, clearly plenty of people are safely conducting (shorter) deco dives in wetsuits. Those dives are outside my experience range, so I don't hold any strong opinion about what exposure protection is best suited for such conditions.

In any case, if you *are* going to dive wet, probably best to choose the lightest possible doubles.

 

[AbyssalPlains]

What about Low Pressure Steel tanks, for example Faber/OMS LP95s? I just checked out their specs: They weigh a bit more than the HP100s on dry land, but are only half as negatively buoyant (about -5 or -6 per tank). When empty, they are almost neutral. Would those be a good compromise to accommodate the dry-versus wet scenario?

 

[Rainer]

This is all pretty simple. Just add up all the relevant buoyancy numbers (cylinders, plate, regs, valves, lights, gas, etc) and see if that's a number you can manage to swim up while doing any necessary deco along the way (i.e. assuming you have no redundant buoyancy).

As to those who said earlier you can't ditch weight, of course you can *if* you're ditching weight that equals the weight of your current back gas, assuming you've weighted yourself to be neutral when the cylinders are (nearly) empty.

What about Low Pressure Steel tanks, for example Faber/OMS LP95s? I just checked out their specs: They weigh a bit more than the HP100s on dry land, but are only half as negatively buoyant (about -5 or -6 per tank). When empty, they are almost neutral. Would those be a good compromise to accommodate the dry-versus wet scenario?

 

[LenC]

Not sure I follow what you've written here. If swimming up HP100s in a wetsuit is causing you such issues that you can barely stay at the surface, how are you planning to hold extended deco stops along the way? I can't imagine getting up steels (especially with appreciable gas in them) in a wetsuit with a failed wing. YMMV.

To the OP, if you're diving wet without redundant buoyancy, the Al80s are probably your best bet.

IMO, if you can't swim your rig up without any buoyancy support, you shouldn't be diving it. Including stops. Once you're on the surface, it's a different story. Then it stops becoming life support equipment and is just dead weight. I agree, you shouldn't be doing this at all without redundant buoyancy. However, what do you do if the same accident that rips your wing also rips your drysuit? Or after you rip your wing you lose your lift bag? There is always one more thing you can do.

 

[Captain12Pk]

... and sorry. I know it's "dived" not "dove" but it sounds wonky to me and I just can't make myself say it.

 

[Rainer]

Then you won't be doing any big dives. No one is going to swim up full double HP130s without any buoyancy support. Just not going to happen.

And seriously, the only thing I can imagine that's going to destroy my wing and drysuit at once is a Great White. I don't plan for unsurvivable events. Waste of time.

IMO, if you can't swim your rig up without any buoyancy support, you shouldn't be diving it. Including stops. Once you're on the surface, it's a different story. Then it stops becoming life support equipment and is just dead weight. I agree, you shouldn't be doing this at all without redundant buoyancy. However, what do you do if the same accident that rips your wing also rips your drysuit? Or after you rip your wing you lose your lift bag? There is always one more thing you can do.

 

[Captain12Pk]

IMO, if you can't swim your rig up without any buoyancy support, you shouldn't be diving it. Including stops. Once you're on the surface, it's a different story. Then it stops becoming life support equipment and is just dead weight. I agree, you shouldn't be doing this at all without redundant buoyancy. However, what do you do if the same accident that rips your wing also rips your drysuit? Or after you rip your wing you lose your lift bag? There is always one more thing you can do.

You could play that game all day. Double wing, drysuit, 5 or 6 liftbags, yada, yada, ya. As a rule you plan for one failure. But if I did have a wing and a suit failure, I'd go to a liftbag. If in the unforseeable WTF event that my bag was somehow gone too; I'd go to my buddy's bag.

 

[ianr33]

I've never dove in openwater that warm. But I have spent extended time in pools in that range, and yes, over enough time, I did get cold.
I dive dry. And even in warm water, I'd dive dry. Unless the water temperature is equal to body temperature, over time body temperature will be lost. It also eliminates the question about redundant bouyancy that arose earlier.
Again, this is just my opinion. That's what I would recommend. You can do it however you want.

I've done quite a few deco dives in Cayman. Water temp low-mid 80,s. Air temperature low 90's.
Can't imagine wearing a drysuit in those conditions!
Am plenty warm enough after 90 minutes wearing a 3mm wetsuit,thin hood and fingerless gloves.

Each to their own.

 

[liuk3]

I've done quite a few deco dives in Cayman. Water temp low-mid 80,s. Air temperature low 90's.
Can't imagine wearing a drysuit in those conditions!
Am plenty warm enough after 90 minutes wearing a 3mm wetsuit,thin hood and fingerless gloves.

Each to their own.

Did a week in Grand Cayman diving in a drysuit. Water temps were in the low 80s, and it felt fine. On the surface, it was warm, but I would just jump in the water to cool off. I'd prefer to be in a drysuit for the redundant buoyancy as well as thermal protection on dives to deeper technical depths.

 

[LenC]

Then you won't be doing any big dives. No one is going to swim up full double HP130s without any buoyancy support. Just not going to happen.

And seriously, the only thing I can imagine that's going to destroy my wing and drysuit at once is a Great White. I don't plan for unsurvivable events. Waste of time.

Your priviledge. I personally don't make plans which put me in an unsurvivable event. As to big dives, that is why God made CCRs. Which I can also swim up if I need to.