Unpressurised Dry Suit for Shallow Surface Supplied Air Diving

[Orthodoxality]

Hello!
I have an opportunity to do some surface-supplied diving at depths smaller than 12m for videography (I only have experience with regular SCUBA, but will practice in a pool at a nearby club.)

Unfortunately, the water in Ireland isn't particularly balmy a lot of the year, and I was wondering about using a drysuit. I see threads here when divers say that the squeeze isn't so bad down to 20m, with others describing a contrary experience. Venues like "Silfra Iceland snorkeling" seem to offer dry suit diving on a commercial basis, although I don't know whether they descend with them.

Is there any consensus on the board regarding the viability of shallow diving with a dry suit?

Thank you for your time!

 

[grantctobin]

If you start with huge amounts of excess gas in an oversized suit, you’ll likely be alright. I would struggle to get to 6m and retain mobility without adding gas to the suit.

 

[ofg-1]

Wear a wet suit under it. Not as warm as a good undergarment, but will not squeeze you as bad. Or, find a neoprene drysuit.

 

[Kendall Raine]

Hello!
I have an opportunity to do some surface-supplied diving at depths smaller than 12m for videography (I only have experience with regular SCUBA, but will practice in a pool at a nearby club.)

Unfortunately, the water in Ireland isn't particularly balmy a lot of the year, and I was wondering about using a drysuit. I see threads here when divers say that the squeeze isn't so bad down to 20m, with others describing a contrary experience. Venues like "Silfra Iceland snorkeling" seem to offer dry suit diving on a commercial basis, although I don't know whether they descend with them.

Is there any consensus on the board regarding the viability of shallow diving with a dry suit?

Thank you for your time!

Why not just use a harness/weight belt and rig a small fill bottle. AL6 is plenty for a shallow dive. Piece of 2" webbing and two worm gear clamps and you're good to go. Without that you get suit squeeze (I have no idea what "isn't so bad" means). Squeeze negates the thermal properties of your undergarment, restricts movement (including potential blood flow restriction-read increases risk of DCS) and is a universally silly idea.

 

[formernuke]

Squeeze at 10 ft is uncomfortable. I wouldn't even think about doing 66 feet.

 

[MB NZ]

I wouldn't recommend it, squeeze will be an issue. How about a small cylinder just for suit inflation?

 

[Orthodoxality]

Thanks everyone for the fast replies!

"Not so bad" would be if I got a couple of bruises around the seams and was a little uncomfortable. Significant bloodflow restriction definitely crosses over into "bad".

I had been wondering about a hack like wearing a 7mm neoprene wetsuit under a (neoprene, as per ofg-1?) dry suit with a jumpsuit between them to reduce friction. 12m is practically freediving depth, so I was hoping the pressure might not be that big a deal.

A small cylinder for suit inflation seem like the sensible solution, thank you. It just adds a lot of weight, complexity (and cost!), and the requirement to refill constantly dispels the fantasy of spontaneity enabled by surface-supplied air. Given an emergency pony bottle only being used for a test-breath before diving, it would be lovely to be freed from refilling pumps for an extended journey to a locale.

 

[rfwoodvt]

Bruising and mobility would be your primary problems with squeeze. Even 10 meters will make it difficult for my mobility and I will surely bruise.

 

[OTF]

Drysuits can be dived to any depth from snorkeling at the surface to the very deepest dives. Drysuits require a low pressure inflation connection (just like a BCD) to squirt air in and compensate the pressure inside. Plenty of shops rent drysuits like the Silfra operation does and they're used in all ranges of diving.

Drysuits do take some practice or training to get used to operating underwater. A little instruction or pool practice will get you competent, but they take about 20 dives to really master controlling the air volume inside it. Before achieving that skill it's easy to lose control and float away, which can lead to dangerous lung overexpension or being stuck feet-up-head-down. So don't just drop to 12m with a camera on your first drysuit dive.

It's not feasible to dive an unpressurized squeezed suit like you describe. Even if you tried it, the experience would suck and it's not safe. Squeeze beyond just a meter or two = your undersuit is crushed thin = you will be cold, defeating the purpose of a drysuit. You'll lose mobility, every movement will take more effort and have a limited range of motion. MAYBE you can work through it for a short simple dive - but what if a problem happens?

Why can't you just inflate the suit with a connector from your main air supply, or with a small suit inflation bottle? That's how these suits are always used. Can you tell us more about what you're trying to do and what the limitations are? Can you dive a thick wetsuit instead?

Again I don't know what your situation is, but if you're diving surface supplied maybe look into a hot water suit. You wear a thin wetsuit, like a standard 3mm, flooded with warm water supplied through a hose from the surface parallel to your air. This is actually better than a drysuit if you have access to that setup.

 

[ofg-1]

We used a loose 3 mil suit over long wool underwear in a old bi-lam Henderson drysuit.

You do know that you can tee off the surface supplied hose and inflate your suit?