Question My Wife's Rig is No Longer Balanced. How Do I Add More Ditchable Weight?

[Ryan Neely]

I took my wife out for her first dive of the season yesterday. We were on vacation in February enjoying many tropical wetsuit dives, but yesterday was her first dive in her drysuit since October (so . . . about six months).

The conditions happened to match what I am expecting for an upcoming dive trip to Iceland, so I suggested she test out the additional undergarments we purchased for her just for this trip. "Let's do a trial run so you can decide if you need the thicker undergarments and, if so, how much weight you'll need."

For those interested in specific stats:

The undergarments layer was:
- Brynje mesh base layers (top and bottom) *NEW*
- Meriwool merino wool base layers (top and bottom)
- Fourth Element X-Core Vest *NEW*
- Fourth Element Arctic mid layers (top and bottom)
- Darn Tough merino wool base layer socks
- Fourth Element Hot Foot socks

The environment was:
- Air tenperature: 55 °F (13 °C)
- Water temperature: 40 °F (4 °C)

She dives a Halcyoon Eclipse BC with small hip weight pockets. The BC had a stainless steel backplate and we employ the stainless steel single tank adapter with the in-line weight. I also have a trim pocket installed on the cam band around the tank. We're diving Aluminum 80s.

By the time we added enough weight for her to sink and be able to stay down at twenty feet, she had thirty pounds of steel and lead strapped to her body:

- 6 pounds from the backplate
- 6 pounds from the STA and weight
- 6 pounds in each hip pocket
- 6 pounds in the trim pocket

She was able to hold her safety stop at the end of the dive at twenty feet, but she still had half a cylinder worth of gas (1,500 psi) and she reported struggling to maintain depth at 20 feet. If she had less gas in her cylinder, I don't think she'd have been able to finish the stop.

She has never had an issue like this, and clearly it comes from the additional base layers. We could add more weight, however we have already added four pounds to compensate for the added thermal protection, which seems excessive. (I only add two pounds to my rig to compensate for the same layering and that puts me at 26 pounds.)

So, here's my actual question:

We're adding a lot of non-ditchable weight here. Of the weight on her rig, 12 pounds is ditchable; 18 pounds is not.

At what point do I need to be concerned about finding ways to move that weight to a more discharge configuration, and how do I go about doing that? (e.g., Would the DUI weight harness function with a backplate and wing well enough to help us with this?)

Thanks in advance for any advice you have.

 

[inquis]

The wing should only be compensating for the gas weight. In the event of a catastrophic wing failure, your suit can easily compensate for that small additional amount (6 lb in a full AL80). Ditchable weight not needed in this case.

The main difficulty is a total suit flood. You have the 30 lbs of ballast that the wing now has to handle plus the gas weight. TBH, even with a 30 lb wing, you could easily surface with a total suit flood (which is also very unlikely). Breathing alone can compensate for at least 5 lb, and kicking alone is probably 10-15 lb.

In short, the rig is still balanced, as you can easily surface without ditching anything. Ditch lead at the surface if necessary.

 

[steinbil]

My 2 cents...

¢1: Thicker/more layers of undergarments are more difficult to manage, as not only is there more gas trapped, but the gas moves more slowly. This leads to a little more work venting gas from the drysuit and making sure to hold a proper position to let the gas travel towards the dump, along with the simple fact that there is more gas to expand and a need to vent more frequently. In my early dives, I sometimes felt uncomfortably light at the end of the dive, where I now feel comfortable with the same weight.

¢2: You don't need any ditchable weight when you have redundant buoyancy (drysuit + wing)

 

[Ryan Neely]

Thanks, guys. I was on the fence about this. I  thought that she'd be fine, but I didn't want to assume.

My greatest failure in thinking here was in what weight the wing was offsetting. I hadn't thought about the gas weight and the lead weight in a suit flood. Nor had I considered how much compensation a breath and kicking would offset. That makes me feel better.

If anyone else has anything more they'd like to contribute, I love to learn so please offer more cents if you have them.

Also, @steinbil, do you have suggestions on how to maintain a comfortable thermal envelope with less/thinner undergarments? I'd love to hear your thoughts.

 

[grantmac]

Still balanced, not an issue even with a full flood.

 

[steinbil]

Also, @steinbil, do you have suggestions on how to maintain a comfortable thermal envelope with less/thinner undergarments? I'd love to hear your thoughts.

Most of my comrades up here have electrical heating, which somewhat negates the need for the heaviest undergarments, but it's quite costly and is not without its problems. I definitely wouldn't go that route unless you dive locally in cold water. So far I'm sticking to thick undergarments and just dealing with it. You get used to it after a while. It's usually hands and feet that get cold first, and the hood is important, so make sure you have dry gloves with wool inner gloves and a thick hood. I also use two layers of wool socks.

Of course, you need a bit of air in the drysuit to keep warm, and a little extra weight can give you the leeway to add a bit more air. But unless you have undergarments to trap the air you'll just get a bubble in the suit that won't help much.

 

[rx7diver]

... We're diving Aluminum 80s. ...

Congrats on your upcoming trip to dive Iceland. Can't wait to read your trip report!

Okay. Your wife's Al 80 single is an obvious target. Do you know for sure that you'll be diving Al 80's in Iceland? Or is it more likely that you'll be diving a steel cylinder? If the latter, then I suggest that your wife should try again after sourcing a steel cylinder here.

Also, was your wife testing in fresh water? If your diving in Iceland will be salt water, then you'll need to allow for this, too.

rx7diver

 

[johndiver999]

If she needs more lead then she should wear it. Why not try a weight belt with 12 lbs of lead?

 

[Alekseolsen]

Not very related, bit I have from numerous accounts that the Icelandic outfits are super annoyingly strict at seeing some (plastic/paper) proof of drysuit certifications, even from divers with dive certifications from areas were wetsuit diving just doesn't happen - so get a signature in a logbook from an instructor or something before your trip!​

 

[Ryan Neely]

Thanks everyone.

@steinbil, we do dive locally in cold watet all summer long. Even in August the water temperature barely hits 45 °F below the thermocline at twenty feet. I've looked at heated vests, but I'm not quite ready to pull the trigger yet.

@rx7this was also a concern for me. I'm not certain if we'll be diving steel or aluminum in Icrland . . . and, I had been hoping to take our carbon fiber backplates to reduce luggage weight by not packing steel. That drops her weight down by twleve pounds, forcing her to rely on trim pockets for almost all of it. (We can still get 30 pounds across all the weight pouches, but just. If we're diving steel tanks, I guess that will help some, but you're right, she will need more practice.)

@Alekseolsen, yes, most of the operators I have spoken with do insist on either the card or something like 25 logged drysuit dives (allegedly signed by an instructor). We meet both of those requirements, we're just practicing with new undergarments that have thrown her weighting out of whack.

@johndiver999, she absolutely should wear the necessary weight. My concern was that we were getting into a situation where her rig was no linger Balanced and that I should be trying tonfind a means of including more ditchable weight. After some additional research based on the responses provided here, it doesn't sound like that part is much of a problem. She can wear as much lead as she needs to descend and to hold her safety stop.