Swimming goggles mod to self-equalise?

[adrian.u]

I'm curious if anyone else has tried some kind of mod so normal swimming goggles (well-fitting, no-leak) can 'self-equalise' when freediving(/spearing)?
I can see a few potential benefits: very low volume (little air needed for to eq goggles), nose-clip allows hands-free eq , maybe improved MDR from water on face.

If you have experimented with such a thing, how did you do the mod, and how well did they work?
(Mine seemed fine down nearly 30m, and I reckon could go a lot deeper... -if any freedivers/spearos out there are interested in trying something a bit... 'different'... let me know!)

 

[jochen.marx]

There is the Evolve Apnea FREEQ Goggle, which I am curious about. And the new hektometer google shall come out soon too.

 

[adrian.u]

Indeed, I recall seeing the Evolve FREEQs were 'coming soon' when I was searching to see if anyone was making self-eq goggles (that was probably around the same time I started this thread).

The website says they can be used down to 70m, though it also suggests sensible recreational depth seems more like 40-50m. It mentions "for clear vision", and I'm wondering if that means the air-space around eyes starts to get rather small after that, with the water-holding bags pushing in far enough to obscure the field-of-view...? Still, 40m should be plenty of depth for the majority who are just out to enjoy some freediving rather than competing, and perhaps some spearos would also be happy to use them due to the benefit of hands-free eq.

They are a bit pricey, I think (- but I guess it must be expensive to design and manufacture fairly 'niche' products like this).

One of the things I discovered when I first made my own mod is that swimming goggles do need to have a little bit of pressure difference between inside of the eyepieces and outside - this helps keep them slightly 'sucked' onto the face to prevent leaks. I achieve this in mine using one-way valves that cause some resistance to the movement of air from the external airbags, so air only starts to move into the eyepieces once the pressure difference increases a bit beyond that.

I'm wondering how that works with the FREEQs...? I see there are holes that allow water to move into the internal expanding water 'bags', but doesn't that mean air can get in there when not under the water, which I'd think would prevent such a 'suction' effect until underwater, and might mean they could leak a bit at the start? Presumably, these holes are small enough that, once underwater, the more viscous water only seeps through the holes relatively slowly, which then retains a bit of a pressure difference to keep the slight suction and avoid any water leaking in?

I've only had chance so far to go down about 30m with my own modded goggles, but I'm pretty sure they'd go at least twice that deep, given how much was still left in the airbags afterwards. It's certainly really nice to be able to eq hands-free, as well as not bothering about mask eq at all. TBH, I find them better than any mask I've tried!

It looks like the FREEQs are sold out, so I guess there must be someone out there somewhere who has tried these - would certainly be interested to hear any feedback...

 

[jochen.marx]

Hi adrian.u! That sounds very interesting! Could you maybe show a photo of your selfmade eq-googles?

 

[adrian.u]

OK, here goes...

Granted, it does look a bit, ummm... unusual...! But it works nicely & feels just like wearing normal swimming goggles the whole time - in fact, during the dive I can just forget about it and concentrate on eq of ears, instead of the regular trouble I've had with several 'normal' masks that often seem to just let air out the bottom when I try to eq them.

The goggles also have +2 lenses for my eyesight, so that's helpful too. (Think I need to upgrade to +3 now though...)



As for construction...

I bought a bunch of hydroponics irrigation connectors and some soft silicone tubing off Amazon. Then drilled a hole in the top of each eyepiece and super-glued a corner piece into each one to connect the tubes.

The red things are the one-way valves that prevent water getting into the system, as well as providing a bit of resistance for the movement of air from a couple of bags at the back that get squeezed by the pressure at depth. (Actually a couple of mini beachballs! -covered by some material I sewed around them. I've been wondering about changing it to use a bit of bike tyre inner tube to hold the air instead, but that'd mean finding a way to block up the ends [more glue?] and fit some plastic hydroponics connectors into it somehow to connect up the tubes - and those fit well into the blow-up valves on the beachballs, so that works fine for now...)

The long front tube is for 'recharging' the air bag when on the surface, and it tucks into the hood during the dive (or there's probably a way it could clip onto the string of the nose-clip). The short removable section at the mouth end acts as a 'cap' to prevent water getting sucked up into it at depth.

A potential alternative configuration is to use it without the airbags on the back, forcing air directly from the mouth into the eyepieces as needed during the dive. I've not tried that, but I think it should work fine (and some 'purists' would no doubt prefer it - not to mention that I'm sure using an airbag would be frowned upon during competition - but, fortunately, that's not something I'm ever likely to bother doing, so...)

Altogether, the cost was certainly lower than getting even a pretty basic freediving mask, and it feels & works better than any mask I've tried, so I'm happy with it. (Despite that I'm probably breaking the no.1 rule of freediving... "always look cool"! )

 

[DRW]

The air-bag-behind-the-head concept was used on the series 1 Pirelli Nereide snorkel-mask design during the early 1950s (above), but discontinued on later versions of the device (below).

 

[adrian.u]

Errr... wow... I don't feel quite so bad about how mine looks now...
(Would prefer if the red one-way valves were not so blatant, but I decided to have them nearer the front since I thought longer soft silicone tubes leading to the eyepieces might get squeezed and actually shut off airflow - pressure is a bit lower on that side of the valves, y'see... At some point I might try them further back, hidden in the bag, to check if that does actually turn out to be an issue. If I come across some 'leaner' one-way valves then I'll switch over to those.)

Seems like the amount of air in that vintage mask itself could be even larger than the airbag, so I'd think it wouldn't get very far down before running out? (But maybe it was mainly for snorkelling with a little diving down just a few metres?)

Also, it covers both nose & mouth, so I'm not sure I understand the point of the airbag anyway, when you could just eq the mask yourself? (Though I guess you're gonna need pretty large lungs to keep topping up that much airspace, and still have some left over for yourself! )

-Maybe above explains why it got dropped on 2nd edition?

(I did ensure the airbags on mine have several times more volume than in the eyepieces - probably enough to get down 80m by my calculations...)

 

[DRW]

The Pirelli Nereide diving mask with its built-in snorkel and air bag was a very expensive item in its time and the target purchasers would likely have been Mediterranean spearfishing tourists with deep pockets. Underwater hunting requires long periods to be spent face down on the surface breathing air through a snorkel while stalking prey, which is then chased underwater. The constant presence of a mouthpiece meant that gums could be rubbed raw, hence the attempt at mouth and nose breathing without a mouthpiece.

I posted my message simply to illustrate that there is nothing new under the sun when it comes to underwater product design. The Pirelli snorkel-mask with the air bag was in use 70 years ago.

 

[adrian.u]

Oh, certainly not a new idea - pretty sure I'd heard someone mention some kind of 'air bladder' attached to goggles before I did this.

Going back to the Pirelli, I'm still not sure how much difference it'd make having that size airbag on a mask that large, though?
Looking at it raises so many similar questions for me about how it all would've worked! -Wonder what other engineering it might have to try to deal with some of these things...?
(How do you eq your ears if you can't reach your nose? -Maybe there's enough pressure generated within the mask, if it stays tight on the face, that you can eq a bit if you blow air out of your nose into it? If air can, presumably, go in & out of the top snorkel when you're breathing on the surface, how does it prevent water coming in when underwater? And how does it prevent air escaping from the mask through the snorkel if you do try to eq the mask & your ears when underwater? Is there a float-based shut-off valve, or something, like in some modern snorkels...? -that 'structure' on the top must have some purpose... Etc...)

 

[DRW]

Oh, certainly not a new idea - pretty sure I'd heard someone mention some kind of 'air bladder' attached to goggles before I did this.

Going back to the Pirelli, I'm still not sure how much difference it'd make having that size airbag on a mask that large, though?
Looking at it raises so many similar questions for me about how it all would've worked! -Wonder what other engineering it might have to try to deal with some of these things...?

The world's first French-language spearfishing book, La Chasse aux Poissons, published in 1940 by Raymond Pulvénis, includes imagery of a home-made nose-enclosing diving mask with a frontal snorkel for mouth breathing and with twin enema-style rubber bulbs to blow air into the mask interior at depth:

Note the use of "appareil compensateur" (compensator device) to describe the function of the rubber bulbs. The Franco-Mauritian Pulvénis brothers were credited not only with pioneering Mediterranean spearfishing during the 1930s but also with coining the current French term for a snorkel: "tuba".

Another photo from 1943 showing Alex Kramarenko wearing a nose-excluding "monogoggle" design with air-filled bulbs on either side:

and another photo, this time from The Compleat Goggler, showing Japanese-made goggles with small air-filled fabric covered rubber bulbs to blow air into the eye cups via tubes:

 

[adrian.u]

Thanks for those!
Next time I have someone make some comment about how my goggles look, I'll be able to point them to those pics.

Those last Japanese-made goggles appear kinda similar in style - wonder how well they worked, and what sort of depth they could manage?
I guess if those air bulbs are designed to have a bit of suction that brings in air to refill them automatically when on the surface then that would also provide that bit of pressure difference needed to keep goggles 'sucked' onto the face & prevent leaks, as well as removing any need for the 'recharge tube'.
Must take look to see if I can find something like that I can use for mine...

 

[Cliffordnixon]

To modify normal swimming goggles for self-equalization in freediving, consider adding a small valve or pressure release mechanism near the nose area, which allows for air to escape and equalize pressure without removing the goggles. You can use a silicone sealant to attach a one-way valve or create small holes covered by a flexible membrane that opens under pressure. This design reduces volume, requiring less air for equalization, while a nose clip can facilitate hands-free equalization. Testing these modified goggles at depths of around 30 meters showed promising results, suggesting they may perform well even deeper.