Bolting Down a BP/Wing on a Doubles Rig

[mahjong]

I'm having a doubles instruction class with Frank this week, seriously ya know ;-).

Footnote: For two years I wet-suit dove a full-sized SS backplate with wing nuts, the smallest I could find still wide enough to work. My wetsuit was scuffed up quite a bit at the wing nut points after ~175 dives. And, again, this was a full-sized backplate. I have now switched to a SMALL backplate, and at least from eyeballing doesn't appear to have the "V" depth of the full-sized plate.

I use wing nuts and sometimes the delrins... I've never had an issue with drysuit damage or the tanks falling off the plate. really how far are you walking in your doubles? Once you are in the water there isn't much stress on the bolts unless you are pulling G's on a scooter ya know

(Seriously go to AWS and talk to Frank...)

 

[Thadmn]

That's it exactly! I prefer them to wing nuts.

 

[it_mike]

I went with a 'pad' for this reason. Switching back and forth between singles and doubles in the field, I rely on the wing nuts, but the 'pad' (which isn't padded) covers the nuts.

 

[mahjong]

Just back from doubles instruction and pool work. My instructor went with two Deep Sea Supply Delrin nuts, the ones with five points that you hand tighten (he did concur that the wing nuts would not work with my Oxycheq small SS plate, which is too low profile). I only did some pool work, but the Delrin nuts worked and my tanks didn't fall off. (Had other issues, though; need to ditch the SS plate for an aluminum one and some minor harness adjustments; seems with twin shortie 72's I will need to add almost no weight, in salt water probably no more than 4 lbs; we'll see how it goes tomorrow after we make all the modifications; my Fred-T custom aluminum plate does have a much deeper spine indentation than does the Oxycheq small SS plate).

 

[Akimbo]

This is more a special application solution but I thought it was worth mentioning for others who may read this thread. Think of this as sort of a reverse STA (single tank adapter).

Another approach that I have used on backplates or packs for doubles that didn’t have a deep depression is to make two adapters from ~1/8" stainless flat bar. They were about 1¼" wide x 2½" tall with two holes. One hole is used on the band bolts. The other hole, which is above or below the bands, is used for a carriage bolt inserted through the plate/pack first so the nut is on the back side of the doubles against the adapter plates.

You could make the adapter from a single long piece of flat bar if you want to add weight or have more height adjustment options. Just remember to put the adapter on the back side unless you are willing to fool with assembling using an extension ratchet.

 

[mahjong]

Just a follow up after day two in the pool:

Switched off the DSS Delrin Nuts for some larger and heavier duty hybrid Delrin/brass nuts--these are GREAT! You can really lock down the BP hard with only your hands.

Just back from doubles instruction and pool work. My instructor went with two Deep Sea Supply Delrin nuts, the ones with five points that you hand tighten (he did concur that the wing nuts would not work with my Oxycheq small SS plate, which is too low profile). I only did some pool work, but the Delrin nuts worked and my tanks didn't fall off. (Had other issues, though; need to ditch the SS plate for an aluminum one and some minor harness adjustments; seems with twin shortie 72's I will need to add almost no weight, in salt water probably no more than 4 lbs; we'll see how it goes tomorrow after we make all the modifications; my Fred-T custom aluminum plate does have a much deeper spine indentation than does the Oxycheq small SS plate).