NA-EM1 buoyancy

[tursiops]

Hi again
I measured the the weight of the whole package (Housing with camera, strobes with batteries, focus light, arms, diopter etc...)
all together weight 6.6 KG (approximately 6.4 in salt water)
then I checked the volume of this, 5.3 liter
so it have a 1.1 kg of negative buoyancy.
If I want to keep it a little negative I need just 1 liter of volume.
I will try first to add 2 small bottles to feel if its enough and then decides what to use to float.

---------- Post added May 3rd, 2015 at 09:47 AM ----------

another question
when Nauticam write on the 60x300mm carbon fibre float arm
Weight: 260g
Buoyancy: 460g

the 460g is the real buoyancy force or I have to subtract the 260g and the buoyancy force is just 200g?

I weighed my EM10 and Nauticam housing; it had 12-50mm Macro with Nauticam Macro port, two DS-125, double-handle Flexitray, four 200mm Nauticam arms and 7 Nauticam clamps, Sola 1200, SMC with Flip mount, coil-cord tether. Total weight in fresh water was 4.4 pounds = 1990g. In air, the same rig weighed 16.8 pounds = 7600g. This suggests a displacement of 5.6 liters.

My plan is to replace the two 200mm arms closest to the tray with 90x200mm Nauticam carbon fiber arms, to give me 2x655g = 1410g buoyancy. That will also remove two 200mm arms, which saves another 2x70 = 140g. I'll be at 1550g buoyancy, versus 1990g weight. That's in fresh water, so I'll gain another bit of buoyancy, i.e. 3% of 5.6 liters = 170g. I figure in salt water I'll be carrying 1990-1550 -170 = 270g = 0.6 pounds. I can handle that!

FYI, the 460g listed for the 60x300mm arms is the net buoyancy....you do not need to subtract the 260g arm weight.

 

[Global traveler 67]

I have the Nauticam housing and a few different ports 12-50 W/macro +7 flip diopter, 9-18 with the Zen 170mm MkII and the Pana 8mm with the Nauticam 4.33 dome, 2 S&S DS1's with 5 and 8 inch arms and a single Sola 800 on the hot shoe. I use 4 jumbo floats on the 8 inch arms and remove the 5 inch arms when shooting macro. Overall my rig is slightly negative but light enough to not cause fatigue /drag or be a major issue. Personally I'm really happy with the balance and feel in the water.

 

[Akimbo]

Here is the technique I used and there may also be some values you can use:

http://www.scubaboard.com/forums/the-olympus-outlet/451101-olympus-om-d-nauticam-weights.html

 

[Global traveler 67]

I have a very similar set up, Nauticam EM1 housing, 12-50 port with the Marco option + flip diaopter (+7) and a sola 800, 2- S&S DS 1's with ultra light 5 and 8 inch arms. I use 4 jumbo foam floats and my rig is pretty neutral. I also have the Zen 170mm dome with 9-18mm and the 8mm with 4.33 dome and do no adjust the overall floatation. the floats are on my 8 inch arms and I remove the 5 inch arms when shooting macro. All set ups are pretty neutral and I find easy to manage underwater. I don't have a leash/connection and find the overall function underwater really comfortable.