Nautilus Marine Service

VITROVEX Floatation Spheres

Bild Vitrovex

VITROVEX floatation spheres are composed of two mated hemispheres that are evacuated and locked into position by a sealant and a protective tape. Once the spheres are sealed, the two hemispheres are kept together by the atmospheric pressure on land and the pressure of the water column when deployed.

VITROVEX floatation spheres are sealed during fabrication in a vacuum chamber and are supposed to remain sealed during their whole lifetime.

Precision molding of the highest quality glass, skilled craftsmanship, and strict quality control ensure that VITROVEX spheres show very little deviation in shape even under high pressure. VITROVEX spheres are to a very large degree free of imperfections, and parting plane sealing faces are honed to a precise flatness and finish. However, Nautilus Marine Service recommends checking floatation spheres before and after deployment for any signs of chipping or damages that may jeopardize the integrity of the pressure housing.


The table below shows the characteristics of the most common floatation spheres and their configuration options. This list shall be regarded as a selection guide rather than a definitive list.

If your preferred glass enclosure is not listed, please get in touch with Nautilus Marine Service or your nearest representative to discuss more options. You may also consider our advice before you buy in the download area.

Model series depth rating​ outer diameter wall size​ approx.
net buoyancy
weight in air​
protective shell options vacuum port options​
m inch mm inch mm​​ kg lbs kg lbs
NMS-FS-6700-17 6700 17 432 0.5511811023622 14​​ 26 57 23 51 none, S, RO VP, VPL, VPS, VPR
NMS-FS-7000-13 7000 13 330 0.47244094488189 12​​ 11 24 11 24 none, RO VP, VPL, VPS, VPR
NMS-FS-9000-17 6700 17 432 0.5511811023622 14​​ 21 46 27 60 none, S, RO VPL, VPS, VPR
NMS-FS-10000-10 10000 10 250 0.35433070866142 9​​ 4 9 5 11 none, RO VP, VPL, VPS, VPR
NMS-FS-12000-7.5 12000 7.5 187 0.5511811023622 14​​ 0.5 1 3 7 none VPL, VPS, VPR
NMS-FS-12000-17 12000 17 432 0.82677165354331 21​​ 18 40 30 66 none, S, RO VPL, VPS, VPR
NMS-FS-12000-13 12000 13 330 0.63 16​​ 8 18 11 24 none, RO VPL, VPS, VPR
NMS-FS-6000-20 6000 20 508 0.63 16​​ 41 90 28 62 none VPL, VPS, VPR

The calculated buoyancy value of 260N for a 17” with 14mm wall size (and all other buoyancy information respectively) is based on the dimensions and the density of VITROVEX glass and the density of seawater. Since the density of seawater varies (1.02 to 1.03) and production tolerances for a particular enclosure may apply, this value is a good approximate; in particular, if VITROVEX spheres are used together with its protective shells. Since protective shell sets are slightly positive, one can safely assume 260N for doing any buoyancy calculations. However, without protective shells, one may reduce the given buoyancy value by 5N.

Nevertheless, Nautilus Marine Service always advises considering a safety margin in your buoyancy calculations to reflect other influences such as current or temperature changes or miscalculations on the actual weight of the equipment.

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7416 Cabrillo Avenue, La Jolla, CA  92037, United States