Subal Ports: A Tale of Two O-Rings

[frogfish 5]

A friend once told me she thought u/w photographers might make good partner-marriage material. "After all", she said, ripping off the wonderful line from Joan Rivers, "you're already used to spending money on neat non-essentials, you exhibit patience and a willingness to delay gratification, and you've experienced lots of pain."

 

As many here already know, I experienced the pain of my second flood in a lifetime a few weeks ago. The problem was the o-ring on a 50 mm port extension ring, which was not seated properly because it was the wrong size.

 

This doesn't concern anyone who has purchased a Subal housing and ports new recently or is about to do so, but as anyone who has acquired a motley collection of newer and older Subal ports and extension rings is probably already aware, Subal changed their port-o-ring specification a few years ago.

 

The groove in all the newer ports and extension rings is configured for a 3 mm o-ring (Part ORPTB3) while older ports and rings require a 2.6 mm O-ring (ORPTBJ). If you compare the two o-rings side by side, it's fairly easy to distinguish them, but looking at a port or extension ring, it can be difficult to tell whether it takes the old or new style o-ring. Except for the width of the o-ring groove, older and new models of ports and rings manufactured before and after the changeover are almost indistinguishable. There is no special mark or instructions on the new ports and rings telling you which kind of o-ring to use.

 

I knew that my older 105 mm flatport took the old thinner o-ring, while my newer big dome port took the new, thicker ring, as did the 50 mm extension ring I normally use with the domeport when shooting with the 12-24 or 17-35 zooms. I've done a pretty good job of keeping the two different size o-rings straight over the years, but what I didn't realize is that my second 50 mm extension ring was older, and takes the older ring. On this occasion, I either mixed up the extension rings, or else I may have pulled the o-ring off the 105 mm macro port (thin style) and put it on the extension ring (new style) in a hurry. I'm not sure which, and the shitty lighting that in my room at the Paradise at Tulamben didn't help, but that's more or less how I ended up having a flood. Similar problems might have been the cause of John Bantin's recent Subal FS2 flood as well.

 

NOW (too late), I do know how to tell for sure which o-ring a port takes. The trick is to look at the thickness of the flange next to the o-ring groove. Subal has made this flange thinner on the newer ports and rings to allow room for the wider o-ring groove. If you compare two ports, one taking the old style o-ring and the other the new, the difference is unmistakeable. (See diagram, which I requested from Subal so that I could sort out once and for all which size o-rings and ports/rings are which.) I have added pointers to the flanges I'm talking about in their diagram so you can see what I mean.)

 

Frogfish

[Kelpfish 15]

Man that blows. You'd think that Subal would identify the o-ring somehow by color. So how do you tell the difference between the o-rings themselves? A caliper? I mean .4 mm ain't much for my bad eyes to detect without some form of measuring device.

 

Sorr to hear that, Robert. I'v had a few floods as well, 2-3 on Subal and two on Nikonos cameras. They are the reason I drink.

 

Joe

[sharky1961 2]

hi,

 

I also head a minor flood because of the o-ring size. I was really pissed

because I had everything double chequed, later I found out that it was the diffrence in O-Ring size. So I sent my 60mm Port back to Subal and they adapted the O-ring groove so that the new O-rings fit in, so now I have all the same size O-rings for my different ports. So I would advise to all Subal users with old ports let them service and adapted to the new O-rings so you would not flood your housing because of this.

 

 

 

Rob

[Photobeat 0]

Thanks for sharing that - who would have any idea? I wonder if other manufacturers have done this. When I order O-rings or add ports you can be sure I will double check that stuff. Did you loose everything, camera and lenses? A story like this will keep me from taking a 12mp body underwater I think. Hope you get over the pain, I guess the real pain is the replacement cost. OF course it is a great excuse to get better stuff though.

[UWPhotoTech 0]

Another method to determine which o-ring is required is to look at the o-ring seat on the port. The old style (2.6mm) has a tapered seat and the new style (3.0mm) has a flat seat. This is shown in the image posted above.

 

Also, every Subal Port and Extension Ring ships with a sticker notifying you of the o-ring design change.

[frogfish 5]

As floods go, it wasn't as bad as it could have been. I lost one S2Pro body and a 12-24 lens. The lens was the biggest loss. Had this happened next week, it would have been the D2X. This trip was supposed to be my last dives with the FS2 housing. (And it was, it's just that now I won't be selling this housing until it's back from servicing.)

 

It's easy to tell the two kinds of o-rings apart when you have one in each hand. What's harder is, with just one o-ring in your hand and a port on the table in front of you, knowing whether that's the right ring for the right port. So yes, I do carry a small plastic caliper gauge in the u/w toolkit. (It sometimes comes in handy for other things too.)

 

I do want to stress again that this is NOT a problem for anyone who has bought Subal gear recently, or who may be considering doing so now. All your ports and extension rings will be new style and all your port o-rings the same. It is only an issue for people who have been with Subal for awhile and have aquired both new-style and old-style ports and extension rings, or who are buying used Subal gear. In any case, the issue can be dealt with by being careful and well organized.

 

I didn't realize that old-style ports could be modified to take the larger o-ring. That would be a better solution that runnings two nearly identical kinds of o-rings on the same brand of of gear. I plan o sell all my old-style ports (except the MF 105) and rings I have as a package together with the FS2 housing.

 

UWPhotoTech.: Yes, the paper tag (not a sticker - that would be nice, unless this is new since I last bought a port) that Subal ships with new ports and rings does say which type of o-ring should be used. Having received that tag doesn't necessarily tell you which of two different o-rings, both black, of identical overall diameter but slightly different thickness, you have in your hand at 6:30 in the morning in a badly lit bungalow while rushing to get ready.

 

I don't mean to criticize Subal here - I'm a fan. (I must be - at the moment I happen to own three housings.) And this flood, like most, was definitely caused by stupidity and carelessness - mine. But I do think that it would have been better had subal arranged for the 3 mm O-rings to be a different color and stamped in an obvious marking (ideally colored as well). This probably could have saved a number of floods, including mine. Failing that, I think it's important that any Subal owners who could be affected by the o-ring issue know about it.

 

Frogfish

[TimG 62]

Hi Robert

 

I'm really sorry to read about your flood - but many thanks for the very useful drawing illustrating the issue.

 

I bought my D10 Subal housing and ports just over a year ago. Both extension ring bags were marked with stickers saying they contained new, wider o-rings. And the FP-90 port I bought has a blue o-ring rather than black......

[UWPhotoTech 0]

I bought my D10 Subal housing and ports just over a year ago. Both extension ring bags were marked with stickers saying they contained new, wider o-rings. And the FP-90 port I bought has a blue o-ring rather than black......

<{POST_SNAPBACK}>

 

Blue O-Ring? Sounds like you may have a Sea & Sea o-ring on there!

[ulcs 0]

I had some ports come with blue o-rings right after they came out with the larger groove. Wish they had stayed with the blue; but I am sure they had their reasons.

I mark all my ports and ext rings on the inside as to what o-ring to use since I have such an assortment of both

Terry

[jcclink 8]

More parts means more chance of an error in assembly. Sounds like the new fatter o-rings are the blue compound (whatever that is), & the compound was changed to aid in proper identification of the size. Do the blue ones require "special grease"? The safest thing to do is to have the old ports modified to accept the new size o-ring, & use the correct size buna (black) o-ring instead of the blue one. Then you're back to all black o-rings that require just a good grade of generic silicone grease as lubricant.

[UWPhotoTech 0]

I had some ports come with blue o-rings right after they came out with the larger groove.  Wish they had stayed with the blue; but I am sure they had their reasons.

I mark all my ports and ext rings on the inside as to what o-ring to use since I have such an assortment of both Terry

<{POST_SNAPBACK}>

 

Hi Terry, I checked with Fred (the Wizard) and Kelly (the Keeper of all Information) here at UWPT and none of us has seen the blue Subal o-rings. It may be that they considered a color change when they went to the "new" (about five years ago) design. FYI, all of the new ports and extension rings are designated with a /3 suffix on the package.

 

Thanks for dinner in Florida, I was honored to be your official show chauffeur!

[Stewart L. Sy 12]

I've got a mixed set of Subal ports too. However, I find that keeping the orings in separate labeled zip-lock bags helps. I also have stickers on each port identifing which ones needs which thickness O-ring.

 

If the new and old O-rings are side by side, it's actually pretty easy to tell them apart.

 

Stu

[frogfish 5]

I do the same, separate labelled zip loc bags for the 2.6 mm and 3.0 mm (and another for the Ikelite SS200 o-rings which are almost the same overall diameter, but even thicker. I agree it's fairly easy to tell the apart if you have the two side by side.

 

My problem came (I think) because I transferred an o-ring form my macro port (small size) to a 50 mm extension ring which I thought also took the same size ring, but it turns out that my two 50 mm extension rings take different size o-rings, and I didn't realize I was using the ring that takes a larger ring.

 

Just one of those little things....

 

Frogfish

[TimG 62]

The blue rings are not advertised as needing special grease! TAnd mine sure are getting plain ol' regular silicone and seem fine.

 

Like Terry, I think its a pity they didn't stay with blue for the new ones. They certainly are easy to spot and check.