Halcyon STA Question

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HenryUK

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27
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Location
United Kingdom
# of dives
50 - 99
I recently purchased a second hand Halcyon set up, but when I removed the STA to add an STA weight I realised that the top bolt hole has been cut….

Please see the image which tries to depict what I mean (red line being where it’s cut) - I can upload a photo is needed…

My question is, why would anyone do this, it seems to be quite solid but my concern is that a knock (in cave/cavern or wreck) when back finning could dislodge the top screw and result in my tank and STA coming unattached from the backplate and wing… any ideas welcome, do you think it would be ok to use in open water (I.e. not an overhead environment) or best just to get a new one right away?

Thanks,
 

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A better picture may help but I don’t see anything that would be an issue.
 
I guess it didn’t match perfectly with the holes on a backplate at some point and someone cut it to make the hole distance more flexible. Many backplates have a slot instead of the lower hole to mitigate this issue. I don’t see that being a problem, it’s not going to be able to move anyway when bumped as long as the other hole has a bolt through it.
 
I guess it didn’t match perfectly with the holes on a backplate at some point and someone cut it to make the hole distance more flexible. Many backplates have a slot instead of the lower hole to mitigate this issue. I don’t see that being a problem, it’s not going to be able to move anyway when bumped as long as the other hole has a bolt through it.
very likely this... I had to have my dgx steel plate modified by a machinist buddy to match up with the slots on a Halcyon wing.
 
I recently purchased a second hand Halcyon set up, but when I removed the STA to add an STA weight I realised that the top bolt hole has been cut….

Please see the image which tries to depict what I mean (red line being where it’s cut) - I can upload a photo is needed…

My question is, why would anyone do this, it seems to be quite solid but my concern is that a knock (in cave/cavern or wreck) when back finning could dislodge the top screw and result in my tank and STA coming unattached from the backplate and wing… any ideas welcome, do you think it would be ok to use in open water (I.e. not an overhead environment) or best just to get a new one right away?

Thanks,
Why would you be using an sta in an overhead environment?

Just flip it over so the slotted hole is on the bottom. If the top bolt index’s it properly short of the top bolt breaking I don’t really see a way for it to shift forward or backwards with the weight installed. Without the weight there is a possibility that the bolt might come loose enough to slide down. If you’re using a backplate with a slotted lower hole

Just take it to your local welder and have them close up the gap
 
A better picture may help but I don’t see anything that would be an issue.
Sure, please see attached… I’m glad its nothing serious, as recommended below I have turned the STA around so its bolted at the top…
 

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I guess it didn’t match perfectly with the holes on a backplate at some point and someone cut it to make the hole distance more flexible. Many backplates have a slot instead of the lower hole to mitigate this issue. I don’t see that being a problem, it’s not going to be able to move anyway when bumped as long as the other hole has a bolt through it.
Thanks for your reply, that makes sense…
 
very likely this... I had to have my dgx steel plate modified by a machinist buddy to match up with the slots on a Halcyon wing.
Yes, makes sense… I was surprised as it’s all Halcyon (BP/W and STA) but perhaps someone was using the STA with a different BP/W so needed to cut it to fit
 
Why would you be using an sta in an overhead environment?

Just flip it over so the slotted hole is on the bottom. If the top bolt index’s it properly short of the top bolt breaking I don’t really see a way for it to shift forward or backwards with the weight installed. Without the weight there is a possibility that the bolt might come loose enough to slide down. If you’re using a backplate with a slotted lower hole

Just take it to your local welder and have them close up the gap
Thanks for the advice, I have now turned it around so the hole is at the top and the slotted hole is at the bottom. It seems quite secure, I was just surprised to see it as it’s a Halcyon STA & BP/W so should all line up and fit perfectly… perhaps someone was using the STA on a different BP/W so needed to add the slits for it to fit.

Using the STA in overhead environments: i am planning a trip to Malta / Gozo and they have some small caverns and penetrable wrecks (all recreational dives, nothing too challenging) and I was concerned that a knock might force the screw backwards and out of the slot hole - but I think turning it around would solve that issue and as someone said, short of the bolt breaking it shouldn’t come apart.

But I’ll see if I can find a local welder and get it patched up… better to be safe then sorry.
 
https://www.shearwater.com/products/perdix-ai/

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