heavy rig buoyancy help

[1nfinite]

Anyone help me figure out how much lift I need to get my rig neutrally buoyant. I suck at maths.

My rig weighs 5kg & Im going to purchase some Stix jumbo floats for the arms which have 0.77 kilo lift x4 I was hoping 8 floats would be enough. Thats 1.5 kilos lift.

 

[npole]

It's impossible to know without having the real volume of your rig, the real weight (outside of water) doesn't count (or the boats won't float!)... the only thing you can do is to submerge it and measure the (in water) weight yourself.

 

[1nfinite]

Ok thanks npole i will try in bath.

 

[Barmaglot]

Keep in mind that in fresh water, it will be a bit (about 3%) less buoyant than in the ocean; i.e. if you get your 5kg rig perfectly neutral in a bathtub, it will go ~150g positive in salt water.

 

[charlesml3]

Yep. You'll need a fish or luggage scale. Cheap on Amazon. Tie a string to the rig, put it on the scale and lower it into the water. This will give you the weight while submerged. Then you can figure out how many floats you need from that.

 

[1nfinite]

Camera weighs 1.80 kilo underwater - 3% =1.74 Kilo
Floats give 154 lift
20.6G negative.

 

[npole]

Seems obvious, while measuring the weight don't forget to place the batteries inside every equipment... and they must be charged!

(OK the charged part was English humor... not easy to get...)