Fifish V6 expert Neutral buoyancy...

[Bluesky Lee]

Fifish V6 expert Neutral buoyancy problem.

1. It cannot maintain neutral buoyancy and sinks.
==> If you press the lock button (key shape) on the remote control, the drone stops working and sinks.
After using the drone, it is difficult to retrieve it out of the water.

2. As a temporary solution, I purchased <Car door guard> and attached it. It is recommended that the rov have some positive buoyancy. Only then can you float on the surface.
* V6: 3.9 kg
* V6 s: 4.1 kg
* V6 e: 4.6 kg
The appearance and volume of rov have not changed. Qysea compared to V6 as it became heavier, design considerations for neutral buoyancy should have been taken into account. I should have added some buoyancy or something. I calculated some positive buoyancy to V6 e, which is 0.7 kg heavier than V6, and temporarily attached a sponge buoyancy material.

3. Additionally, it is difficult to put the rov on the floor out of the water.
Rough road surfaces such as gravel, rock, sand, etc. may be scratched or damaged. Qysea should have thought of something that could mount the rov (like a helicopter leg). It would be good to consider adding a cradle as an accessory. (Sponge does that role temporarily )

 

[Rickard]

Hi,
Have you tested the ROV in water with the extra buoyancy material on? I'm qurious the learn if neutral buoyancy has any effect on the ROV's stability. Perhaps it's easier to control depth in "depth hold mode" if buoyancy deviates from neutral?
Also, I have used two V6s ROVs and both sink. If I activate "depth hold" and position the ROV at an angle (about 45 degrees) pointing to the seafloor the ROV will start moving forward slowly although there is no control input. This is sometimes really annoying and it would be good news if that unwanted movement disappears when the ROV gets neutral buoyancy.
Regards, Rickard

 

[Rickard]

Now I have made my V6s neutrally buoyant using four 250 mm long peices of round wood (pine) with diameter 30 mm. I had to seal them using epoxy. Two pieces are attached to the top and two at the "belly". The result is really pleasing since now I can park the ROV one inch above the seafloor without stirring up silt.

 

[Zhenya88]

Please foto.

 

[Bluesky Lee]

Hi,
Have you tested the ROV in water with the extra buoyancy material on? I'm qurious the learn if neutral buoyancy has any effect on the ROV's stability. Perhaps it's easier to control depth in "depth hold mode" if buoyancy deviates from neutral?
Also, I have used two V6s ROVs and both sink. If I activate "depth hold" and position the ROV at an angle (about 45 degrees) pointing to the seafloor the ROV will start moving forward slowly although there is no control input. This is sometimes really annoying and it would be good news if that unwanted movement disappears when the ROV gets neutral buoyancy.
Regards, Rickard

Yes. With the addition of buoyancy to the ROV, we have, of course, conducted actual tests at sea several times.
(Because we own a relatively large fishing boat)
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1. ROV is also positioned like a submarine. In order to float in the water, you need to adjust your neutral buoyancy accordingly. Only then can you reduce battery consumption.
2. The FIFISH V6 Rov maintains neutral buoyancy by continuously operating the electric motor thruster (thrust).
We are solving the problem of neutral buoyancy by floating underwater.
However, this method has the disadvantage of only exacerbating excessive battery consumption as it continuously operates the four electric motor thrusts non-stop.
3. Fill and evacuate the MBT (Main Buoyancy Tank) with 100% accuracy as shown in the video linked above.
It would be the best way to apply the buoyancy control principle of a real submarine, but it would be a high cost problem.

 

[Rickard]

Please foto.

Simple and provisional but it works. (Really hard to attach photos!)

 

[Bluesky Lee]

Simple and provisional but it works. (Really hard to attach photos!)


View attachment 976View attachment 977

As shown in the video below, after using the drone in the sea with the added buoyancy material installed, the drone is immersed in a freshwater tank to remove salt.
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*As you can see, the underwater drone is not sinking and is maintaining some positive buoyancy.