Rig buoyancy-

Hi everyone.

My main question is what is a decent slightly negative bouyancy to aim for?

My rig =

Oly epl3

Oly pt-ep05l

X2 8" ulcs arms and clamps

X2 inon S2000

Nauticam flexitrsy.

I have done the water butt experiment. (Tied a line to housing dunked it and used kitchen scales to measure.( only ones I had delicate enough to get a measurement. )

Started off with x2 jumbo stix floats on each arm and it just bobbed on surface. Haha.

Then went for x1 jumbo stix float on each arm. And measured 250 grams negative

Is this a sensible negative buoyancy. I'm diving in a few weeks and want it to be right.

What are other peoples experiences. Any help/tips will be greatly appreciated.

Many thanks.

Hi,

Just check how quickly it sinks. It should sink very slowly.

I would guesstimate that 250g is ok, but not 100% optimum

/Erik

I like my rigs to be negative enough to be able to place them on the bottom and not drift in most normal current situations. This usually is around 2 pounds negative. also make sure that the distribution of flotation is such that it is easy to hold on target.

I have my rigs almost perfectly neutral buoyant with a micro negative tendency so can "put" them in front of me wherever i am if i need my hands free,

except in current and me holding a mooring line or similar.

One other solution i like is to have them enough buoyant that you can swim or drift and the housing float above you on a 3 ft cord,

especially for small rigs.

Chris

Thanks guys. I was thinking maybe x1 large stix float on each arm with the Jumbo stix.

How does this sound? Is this wise? Or x2 large stix on each arm?

Forgot to say. Using the zen WA-100 dome port.

measure how much the Jumbo Stix floats,
take a ruler and cut a corresponding part till you have the desired buoyancy.

Then cut the right sized piece in half and stick each on a arm.

And enjoy your right weighted rig!

Chris

Thanks chrigelkarrer. I think I read the 4 large stix have lift of 13.5oz (382g) am gonna use 2. And this hopefully will leave me with roughly 60grams of negative buoyancy.

.

If your measure is accurate your rig is 570 grams negative (seems little how heavy is the nauticam tray?)

If you want to make it almost neutral you need 2x large + 2x jumbo = 516 grams lift add another 45 grams in salt water the rig will be neutral however it is weird to have two different size of floats.

4 large stix are 396 grams so you would be left with 170 grams in fresh water add another 45 grams for salt water 125 grams. I would think this is the best set up

Your housing is only 30 grams negative with the kit lens in fresh and will probably be slightly positive or neutral in salt water

Hi interceptor. Thanks for helping mate. That was reading I got. Albeit it was a little all over the place. .

The nauticam handle and tray weights 459g. ( taken As per internet.)

I'm gonna try x1 jumbo each arm next week. Diving fresh water and see how that feels. If not I'll buy a set of large stix. I think I want it slightly negative so when I tether it to use both hands for something it doesn't keep smashing me in the face. . Hahaha.

Hi interceptor. Thanks for helping mate. That was reading I got. Albeit it was a little all over the place. .

 

The nauticam handle and tray weights 459g. ( taken As per internet.)

 

I'm gonna try x1 jumbo each arm next week. Diving fresh water and see how that feels. If not I'll buy a set of large stix. I think I want it slightly negative so when I tether it to use both hands for something it doesn't keep smashing me in the face. . Hahaha.

The nauticam handle weight will be on land, the handles are plastic so will float. I think around 200-300 for the lot.

If you make yourself a locline for a focus light you can stick another float on the arm

What you mean 200-300 total?

I was thinking instead of gettin the large stix floats. From my measurement I need to gain around 170g buoyancy from the floats for both fresh and salt. This will give me the slightly negative buoyancy I'm after. I might just cut one jumbo in half.

X4 jumbo =680g

X1 jumbo =170g!!!!

How that sound mate?

Save myself few pennies.

I meant in water the tray will be 200-300 grams negative

4x jumbo is 635 4x large is 396. Do you own already some? If you have jumbo and are happy with that you can cut them to adjust

Generally you add 3% to land weight of your neutral fresh water rig that you can easily determine say you have 3 kg you gain 90 grams. I have a 5.5 kg rig that is 165 grams.

Yeh I have x4 jumbo's. I think I will just cut 1 in half and add to each arm. Should leave me about where I want it negatively.

I'm going to get the zen dome and 45mm panasonic macro lens. I take it I will need more stix floats( I will go through the process of weighing in water butt again) plus I see stix do a macro port float strap thingy. Any good? Have u used one?

Just a quick one. Have you measure

Your rig the way I explained I did with water butt. If so what scales did u use as I tried various and had to settle with the kitchen style digital as they we only ones to record a low weight in grams??!

Thanks mate

I have one. In fact I would sell it to you if you want it as I don't have a port anymore

The zen dome is glass will be somewhat heavy

I use a luggage scale put attach the rig to it and then put in water and read negative weight

Will it fit the zen port? Did u use it on this port?

I tried both digital and analogue luggage scales but the rig just wasn't heavy enough to get a me reading. I tied a line to rig then made a loop and hooked over kitchen scales and got a reading that way.

Will be my first dive next week with arms/strobes etc. Can't wait. :)

Depends on the shape of the housing you can tweak things a little

I tried both digital and analogue luggage scales but the rig just wasn't heavy enough to get a me reading.

I had this problem... it turns out you can get luggage scales that have difference accuracies

What you need is :

http://www.amazon.co.uk/Portable-Digital-Luggage-Travel-Hanging/dp/B00EC8C5MC/ref=sr_1_19?ie=UTF8&qid=1397140144&sr=8-19&keywords=luggage+scales+5g

I got a set of these locally (and a Chinese Bizarre cheap shop) for like 5e. its accurate to just 5g. Weight mine, bloody -1.170kg negative!!!

Thanks trickster will take a look.

Interceptor. It fits to the port right.

http://www.backscatter.com/sku/na-fp-100-45.lasso

Yes that port is the correct port for the 45mm lens and the PT-EP05L Housing.

(I had the same camera/housing previously, if you need any further info)

Great cheers mate.

Did you have the pana 45mm macro and port. If so how did u find it?