OP
Jim: I put the pic of my arms in my post. I should have done this earlier.
2 simple questions
- Thread starter Compressor
- Start date
Please register or login
Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
- Ability to post and comment on topics and discussions.
- A Free photo gallery to share your dive photos with the world.
- You can make this box go away
From what I see on Bluewater photo's page, these may work. Beneath the Surface Buoyancy Floats
The Beneath the Surface arms are round and the balls don't appear to come off. So the floats I'm guessing are split to allow them to be installed. Call Bluewater. They are really helpful. Or email them and see what they say.
It's either this or maybe go with the buoyancy arms from Inon, 10 bar, or ultralight. I went with the foam just to see because I did not want to drop more money in new arms. I've got $400+ in the arms and clamps I have now!
The Beneath the Surface arms are round and the balls don't appear to come off. So the floats I'm guessing are split to allow them to be installed. Call Bluewater. They are really helpful. Or email them and see what they say.
It's either this or maybe go with the buoyancy arms from Inon, 10 bar, or ultralight. I went with the foam just to see because I did not want to drop more money in new arms. I've got $400+ in the arms and clamps I have now!
OP
Thank you Jim:
Well I think before I purchase anything and perhaps I posted here, I should have actually tested the system and see how negative its going to be. A bit negative should not be too bothersome. Will dive with 1 strobe and see how things go then go with 2 strobes. While not the exact same system, the owner of the strobes before me told me that his system was slightly negative which is what @dhaas also mentioned. I had thought that it will be very negative.
I have sent Bluewater email and waiting for reply.
Well I think before I purchase anything and perhaps I posted here, I should have actually tested the system and see how negative its going to be. A bit negative should not be too bothersome. Will dive with 1 strobe and see how things go then go with 2 strobes. While not the exact same system, the owner of the strobes before me told me that his system was slightly negative which is what @dhaas also mentioned. I had thought that it will be very negative.
OMG!!!!!
I have sent Bluewater email and waiting for reply.
Chris Ross
Contributor
The simple way to work it out is to assemble everything (camera/lens in housing, arms, strobes etc) hang it off a luggage scale you can pick up for a few $ then weigh it is sink or bathtub, making sure its fully submerged. It will be more buoyant in salt water, but not by that much. Something with a volume of 1000 cm3 will be 23 grams more buoyant in salt water than fresh. That way you can be reasonably certain the rig will be right when you arrive at your dive site.
Once you have the weight most buoyancy arms will be labelled with their buoyancy, add enough, so if your rig weighs 600 grams underwater for example, look for about 500 grams of buoyancy arms. You want it slightly negative as if it's positive controlling is quite difficult. If you want to be more precise, add on the weight of any arms you take off the system (removing weight makes things more buoyant) if you replace standard arms with buoyancy arms.
As for lanyards, I use one like this:
Best Divers Smart Coil Clip with Plastic Carabiner - The Scuba Doctor Dive Shop
the clip allows you to shorten the lanyard so it doesn't drift off and bump into stuff when you let go. For shore dives I have this and another clip on the other side to hang the rig on my chest so my hands are free to negotiate rocks, pull on fins etc when getting in and out.
If you are mathematically inclined you can also calculate the buoyancy. Buoyancy is equal to the weight of the liquid displaced, in this case salt water with a density of 1.020 g/cm3. You can get the weights of everything from specs sheets. The weight of the liquid displaced is equal to the volume of the housing times the density is compatible units, for example calculate volume in cm3 and multiply by density in g/cm3 to get the buoyancy in grams.
If I were to guess I would say your rig would be close to neutral with the macro port and maybe positive with the dome.
Once you have the weight most buoyancy arms will be labelled with their buoyancy, add enough, so if your rig weighs 600 grams underwater for example, look for about 500 grams of buoyancy arms. You want it slightly negative as if it's positive controlling is quite difficult. If you want to be more precise, add on the weight of any arms you take off the system (removing weight makes things more buoyant) if you replace standard arms with buoyancy arms.
As for lanyards, I use one like this:
Best Divers Smart Coil Clip with Plastic Carabiner - The Scuba Doctor Dive Shop
the clip allows you to shorten the lanyard so it doesn't drift off and bump into stuff when you let go. For shore dives I have this and another clip on the other side to hang the rig on my chest so my hands are free to negotiate rocks, pull on fins etc when getting in and out.
If you are mathematically inclined you can also calculate the buoyancy. Buoyancy is equal to the weight of the liquid displaced, in this case salt water with a density of 1.020 g/cm3. You can get the weights of everything from specs sheets. The weight of the liquid displaced is equal to the volume of the housing times the density is compatible units, for example calculate volume in cm3 and multiply by density in g/cm3 to get the buoyancy in grams.
If I were to guess I would say your rig would be close to neutral with the macro port and maybe positive with the dome.
OP
Thank you @Chris Ross. I was going to calculate it this weekend as you stated. Archimedes Principle.
Similar threads
