|Arm Length||Amount of buoyancy per arm length|
|8" (DB-BL08)||4.5 oz|
|10" (DB-BL10)||8 oz|
|12" (DB-BL12)||11 oz|
|14" (DB-BL14||14.8 oz|
|16" (DB-BL16)||1 pound 2 oz.|
arm lengths, 1 AC-CSB, 2 AC-CSF, and 1 strobe adapter and 1 base adapter these
are the calculations:
You will need to add in the weight of your strobes underwater to these calculations to get you to the buoyancy you need.
|Arm lengths||Amount of Buoyancy with parts listed above|
|8" & 10"||1.75 oz|
|Two 10"||7 oz|
|10" & 12"||8.3 oz|
|Two 12"||11.2 oz|
|12" & 14"||15 oz.|
|Two 14"||1 pound 3 oz|
|14" & 16"
||1 pound 6 oz|
|Two 16"||1 pound 9 oz.|
The new style clamp (AC-CSB) is
needed to put between the two new arms if you want the arms to come together
when you are handling the whole system topside.
This clamp weighs 1.3 oz more than the regular clamp.
Salt water is approximately 1.026X
more dense than fresh water.
All these tests were done in fresh water
Shows the size difference between the original buoyancy arms
and the new ones and the old clamp and the new clamp
It is important to weigh your whole system underwater. This can be done in a pool, large laundry tub, use rope
to gather the whole set up together and then hang a scale from the rope, keeping the entire unit under the
water. The luggage scale we sell (on the what's new page) can be used for this weighing. Just be careful
not to get the scale itself wet. Once you know what it weighs then you can decide how much of that weight
you would like to take off the system with the sections of the buoyancy arms listed above. Please call us to
discuss results of the above tables and how they correlate to your weighed system. You might want to
weigh your system with different lenses and ports for more accurate diving conditions.
E-mail for a copy of the 2" buoyancy arms weight and measurements chart
An Ultralight arm generally consists of two arms segments and three clamps giving you the greatest flexibility. Videographers sometimes use just one arm segment and two clamps. They do not need the same amount of flexibility as a still photographer does.
The o-ring in the balls of the arms, base adapters, and strobe adapters eliminates the metal to metal contact. This allows a much more linear clamping force, allowing you to control the arm movement when used with small or large strobes even in varying current conditions.
The ball size of our arms and adapters is 1" or 25mm.
Example of two arm segments and three clamps
Double ball arm segments
Original Buoyancy double ball arm segments - were designed for users of heavy cameras and housings. They are constructed of aluminum tubing with the ball ends press fit and glued in. Air trapped inside allows them to be buoyant. See weight & length page for comparisons.
Single ball arm segments - allows you to use one less clamp in the arm set; but reduces flexibility at the strobe head or base
AC-CS -Standard clamp used to attach two arms,
base adapters and strobe adapters together. (Puts 2 ball together)
AC-CSF - Newer style clamp allows 15 degrees side to side movement of the balls
AC-TCS Triple clamp replaces a regular clamp in an arm set, allowing use of
another piece with a ball to be added
AC-TRI - Tripod clamp, has cut outs in the bottom piece to allow for arms to be
used as legs of the tripod so the tripod can be laid completely flat
See tripod on what's new page
Next: Strobe and Light Adapters