ULCS Arms - Buoyancy Arms or Not

[mcgowman]

Hi all,

Have been diving for many years and am seriously considering getting a Nauticam housing for a Nikon D7000 and a pair of Inon Z240's.

My question is about the strobe arms. It seems ULCS arms are highly regarded and well worth the money. However, I am wondering which way to go on the arm segments. ULCS offers the 2" buoyancy arms as well as their 'standard' arms.

Am assuming that the Nauticam rig will be somewhat negative and will need some flotation.

What is the general opinion on the following:
- Would the 2" buoyancy arms be a better choice than standard arms with floats?
- If I go with the standard arms plus floats, should I get the wider clamps (AC-CSB?) so the arms fold up tighter?
- Am I giving up some flexibility in going with 2" arms which I assume have a fixed amount of flotation when compared with foam float segments that can be added/removed as needed?


Thanks to all in advance.

 

[Kilili]

ULCS 2" are great, solid, use larger clamps. Go thru the exercise of determining exactly how much buoyancy you need then spreadsheet to build optimal solution.
My camera needed 10s and 14s. Then, I decided this made the configuration too tall. I swapped out for INON megafloats, then added 3 oz fishing weights, such camera is completely neutral. Can use small Stix floats to do the opposite. I have some large spotter lights, and use Stix to balance these separately. That way I can add or remove things without affecting the overall configuration.

This whole process takes a bit of work, but worth it. I have an oversize housing, but it's a piece of cake to handle underwater.

 

[mcgowman]

Thanks Ken.

I assume by this reference...

My camera needed 10s and 14s.

You meant the arms were 10 and 14 inches long?

 

[Kilili]

Thanks Ken.

I assume by this reference...


You meant the arms were 10 and 14 inches long?

Correct.

 

[mcgowman]

The shop I've been speaking with recommended two pairs of 8" arms (total of four). If I'm reading the ULCS site correctly, it's saying at those lengths, they are neutrally buoyant.

Does that mean they're basically offsetting their own weight? If so, I'd still need additional flotation to help lighten the entire rig, right?

Am wondering if I should get longer buoyancy arms or regular arms with non-compressible foam instead?

 

[Tigershark44]

The buoancy of your rig will vary depending on the port/lens combination you're using for a particular dive. For example, with my Nauticam 550D (a very negative housing) I have 2 general arm/float combos: 1) For the 18-55mm kit lens/flat port and the 100mm macro lens/longer flat port, I use dual 8-inch arms with jumbo Stix floats; 2) for the Canon 10-22mm wide angle lens with a poly 8.5-inch dome port (very positive), I use two 8-inch arms with jumbo Stix floats, two 8-inch arms with no floats, and added a Canon weight to the bottom of the housing due to the housing's inherant tendancy to turtle. If money is an object, I'd get traditional arms, then add or subtract Stix floats as needed. P.S. I also have two 5" arms, two 12" arms, and two 16" arms, but rarely use them.