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ScottyR

How do you balance your rig?

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Recently upgraded to a nauticam housing for an Olympus em1 mkii and I've decided it's time to get some new arms. I've noticed with my previous set ups that my camera was never properly balanced and took a good amount of effort to hold up. With this new rig, its even heavier and actually has me worried. I know the weight characteristics change underwater, but I was planning on upgrading my arms anyways right now. What is a good amount of  buoyancy to start adding?? (i.e. how wide of arms in general or how buoyant?)


Looking at using a 170mm glass port with Panasonic 7-14 and an Olympus 8mm as well as the n85 flat port with the Olympus 60mm. 

p.s. foam floats vs those float arms, is there a real advantage to the float arms or do they just look nicer?
 

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Hi Scotty

I'm assuming you're talking about how to make your setup approximately neutrally buoyant?

If so, you can find a good few posts about using dipping your setup in water whilst dangling on a luggage weighing gizmo. This is an issue that has been discussed many times. 

You need somethign like this:

https://www.amazon.com/Travelon-Grip-Compact-Scale-Silver/dp/B00C75KUK6?ref_=s9_apbd_otopr_hd_bw_b2hesZX&pf_rd_r=60D7BFX78PAQV9MVGB6F&pf_rd_p=1b0ec8fb-c3d3-56d4-8d54-8048cc72bd76&pf_rd_s=merchandised-search-12&pf_rd_t=BROWSE&pf_rd_i=2477391011

Once you know-how much the setup weighs in water, you can add some form of bouyancy to bring it up to, I'd suggest,  just slightly negatively buoyant.

The foam that you can add to arms, such as Stix (which is what I use) is cheap, flexible, long-lasting and easy to add and subtract. Float arms might look nicer, are  much more expensive, and not quite so flexible in terms of adding or subtracting buoyancy. 

But the key, as I say, is to weigh your setup in water so that you know the actual underwater negative buoyancy value. And, yes, if you change any part of the setup then the underwater weight changes and you might need to change the amount of buoyancy you use.

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(and make adjustments for fresh or salt water).

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12 hours ago, Cerianthus said:

(and make adjustments for fresh or salt water).

Indeed :good:

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Two things:

1 - I use float arms for the bulk of the additional buoyancy needed, because (a) they dry MUCH faster for traveling home, and (b) they are more convenient than Stix floats for using.

2 - I tune up the needed buoyancy with a couple of Stix floats on the outer arms. Easy to add-on and remove just a couple. This also allows some adjustment for salt/fresh, which is only 3%, hardly enough to worry about so long as you are ballasted slightly negative for salt. 

 

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I have this setup, I assume you have the Zen 170mm dome.  I have two combinations I use:

170mm dome with 12-40/7-14mm and on each side one INON M float arm and one ML.  Buoyancy is 135+135+210+210 = 690 gr buoyancy.

100mm Zen fisheye dome or 60mm macro flat port one INON Mega float arm S and one 8" nauticam regular arm each side.   Buoyancy is 2x 390 gr = 780 gr.

The dome setup is near neutral and the second combo is too much with the 170mm dome and it goes positive.   The second combo is slightly heavier UW.

I use the Nauticam long clamps as the middle clamp as it allows the arms to fold closer together.  The clamp going on the ball mount on each side is a long clamp with a shackle to attache a lanyard.  The advantage there is the clamp handle does not hit the shackle when attached.

If you want a combo that does both pick the first one - it's 100gr heavier UW, but it works OK. You don't want a positive setup, so the second combo can't be used with the dome.

 

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What is balance?  Or rather what is 'good enough' balance?   I've done no experimentation since I bought my first pair of strobes, for an RX100 rig.   Since then I've moved them to a D810 rig, and now a D850.  I put a pair of STIX floats on each arm in 2015 and haven't looked back since.

I shoot either a 230mm dome port, or a 105mm macro port, with the same floats.    The rig is negatively buoyant, but how much is too much?   And it's still negative with the 230mm port, but not as much and definitely not as balanced.  The dome wants to float up a lot, and so it torques my hands to hold it level.  But not that bad, or I'm just used to it after 5 years now.

Does anyone really change floats between macro and dome port shooting?  I've just never bothered, but I could see maybe adding a bit more flotation and a wheel weight or two under the front of that dome.

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@phxazcraig Great question - "Does anyone really change floats between macro and dome port shooting?"

I don't change floats, but I do change arms ;) My macro setup is much more compact, so I usually bring along enough arm & clamp components to have one set of arms ready for W/A, and one set for macro (I use different arm lengths for each as well). If it's a long trip (more than 1 week) I'll also bring 4 strobes (2 essentially as back up) - so I'll set up 2 complete arm sets. If one of the strobes goes south then I'll start switching strobes when I change arms.

When I shot W/A with my D500 and the large port it drove me nuts with the torque, so with the D850 the WACP is much (much) better balanced, it's just a giant pain out for travel.

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I should add to my post that my strobes are INON Z-240  They weigh 77 gr each in water with batteries.  If you have different strobes it may change your requirements.  INON posts UW weights of all their gear here:

http://www.inon.jp/products/armsystem/weight_table.html

Weights for Sea and Sea strobes are here:  http://www.seaandsea.jp/products/strobe/speclist/a.html

And I do change arms between large dome and macroport or small fisheye dome.

Edited by ChrisRoss

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I've actually had shockingly good success using PVC pipe.  It's cheaper than anything, takes no time at all to make exactly the right size for whatever buoyancy you need, and can be made using sturdy enough to get depth ratings deeper than you can go.

On the down-side, you'll get made fun of every time you pull it out.  Here you are with a $10K camera rig using $3 PVC floats.  lol.  

 

 

Funny related story: a buddy and I were working on a project involving video lights.  We had borrowed a set of 4, each weighing about 2lbs in fresh water.  On a previous dive, we had learned that this negative buoyancy was problematic, so I made super low cost floats out of PVC pipe.  We'd work for a bit, then switch off who had camera+lights and who just had lights.  Turns out that two of the PVC floats were leaking, slowly enough that I didn't realize I was becoming negatively buoyant.  When we went to exchange functions, I took the neutral lights from her, and she took the 4lb lights from me.  Took us both a second to realize what was happening, during which time I ascended a few feet and she bombed into the silty muck.

No harm done, but we still get a laugh out of it.  :)

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I just noticed this thread and want to share a technique I learned from a friend to achieve a desired buoyancy with precision. He uses weights that are designed to balance tires and it works like a dream.  I start off with the Nauticam weights that are screwed into the bottom then fine tune from there with balancing weights. 

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I've actually had shockingly good success using PVC pipe.  It's cheaper than anything, takes no time at all to make exactly the right size for whatever buoyancy you need, and can be made using sturdy enough to get depth ratings deeper than you can go.
On the down-side, you'll get made fun of every time you pull it out.  Here you are with a $10K camera rig using $3 PVC floats.  lol.  
 
 
Funny related story: a buddy and I were working on a project involving video lights.  We had borrowed a set of 4, each weighing about 2lbs in fresh water.  On a previous dive, we had learned that this negative buoyancy was problematic, so I made super low cost floats out of PVC pipe.  We'd work for a bit, then switch off who had camera+lights and who just had lights.  Turns out that two of the PVC floats were leaking, slowly enough that I didn't realize I was becoming negatively buoyant.  When we went to exchange functions, I took the neutral lights from her, and she took the 4lb lights from me.  Took us both a second to realize what was happening, during which time I ascended a few feet and she bombed into the silty muck.
No harm done, but we still get a laugh out of it. 

Cool.
What did you plug the ends with, what diameter pipe and how deep?


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I use buoyancy swimmers that commercial fishermen use for their nets, e.g. these here (but there is a lot of choice of different floats):

https://engelnetze.com/schwimmer-cd-250g-auftrieb-91x45mm-14mm-bohrung

https://engelnetze.com/schwimmer-y30-270g-auftrieb-67x109mm-14mm-bohrung

I widen the opening with a 25mm driller, then they fit over the standard arms. One can cut them (for fine adjustment I have cut both th eupper swimmer types in halves) and drill holes in them and they still do not soak full with water. I never had Stix floats, but I think they are at least as good, probably better, at a fraction of the price. They are good for normal diving (30-50m), but for technical divers they offer floats that are certified for different depth, from 350m up to 1800m, should be sufficient for everybody ...:)

Wolfgang

Edited by Architeuthis

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4 hours ago, MinimalMayhem said:


Cool.
What did you plug the ends with, what diameter pipe and how deep?
 

Your local hardware store sells end-caps for PVC in a variety of sizes.  Just glue those babies on the ends of your pipe.  Diameter and length depend on how much buoyancy you need; just run the calculations for the volume inside the pipe.  Collapse pressure depends on diameter and the weight of the pipe.  2" PVC is rated to something like 300psi collapse pressure, which ought to be plenty.

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7 hours ago, djmcmath said:

Your local hardware store sells end-caps for PVC in a variety of sizes.  Just glue those babies on the ends of your pipe.  Diameter and length depend on how much buoyancy you need; just run the calculations for the volume inside the pipe.  Collapse pressure depends on diameter and the weight of the pipe.  2" PVC is rated to something like 300psi collapse pressure, which ought to be plenty.

I've found the PVC end caps work well too. I've made rattles using PVC pipe, stainless steel ball bearings and end caps. You need to glue the end cap in place (obviously) using PVC glue but I found it works better if you prep the PVC with a primer first.

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