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Pressure rating on motors


(Nicholas) #1

I would like to know how deep the motors and kort nozzles can go. Can they go all the way to 6000m? Is there any depth information on the plastic used in their construction? Deep Sea Power and Light in San Diego has some testing chambers for rent: http://ocean-innovations.net/companies/deepsea/services/pressure-testing-facilities/


(Rusty) #2

Nicholas,

Since there are no enclosed cavities, the limiting factor at depth will likely be material changes due to bulk modulus and different shrinkage rates between different components. If there are any bubbles trapped in the injection molded plastic that may cause issues as well.

The thrusters were statically tested to 3000m depth by Woods Hole Oceanographic Institution but we have not had a chance to actually run them at such depths.

I hope that helps! Sorry we don’t have more testing info yet!

Best,

Rusty


(Harold Scadden) #3

@Nicholas - Frankly these motors should work to the bottom of the ocean … or at least survive the trip. I think Rusty already spoke of the worse issues at hand. Frankly if it made it to 3000m that is more than anyone on this site should be dealing with. Out of curiosity, what do you plan on sending down to 6000m?

 


(Nicholas) #4

I don’t have $2/ft for 10,000 ft! For the moment my goal is simply to go beyond the reach of ethernet tethers (maybe 2000ft?).

I know that I CAN make a 6km ROV housing and structure that can produce HD video for less than $8000, (not including tether and winch system, which is going to be expensive). It’s all because of these new thrusters (and the Rpi2B, and a lot of other recent tech).

One of my biggest concerns is thruster power. Most deepwater ROV thrusters are in the kW range because of the current drag on the tether. I like the power, but not the pricetag (at least $1000 per electric Kort nozzle thruster, and more for hydraulic ones). The T200 thruster is within 1 order of magnitude power for 2 orders of magnitude less price. Hopefully they are developing a T1000 or T1kW, for $400.

Blue Robotics can disrupt this industry big time. I want to be one of the first to take advantage.


(Harold Scadden) #5

@Nicholas, where are you getting your tether from? In addition, is it possible to have ethernet of a 2000 foot cable? I am not a network type, so that is why I am asking about how far you can push a signal and at what speed.

What do you plan for a shell housing for a 6km dive? Just curious.

 


(Nicholas) #6

Ethernet is limited to about 300 feet, or maybe 300 meters. (I’m not really a network guy either :P) I am using fiber. Falmat and several other companies in my local area (619) specialize in fiber optic cables for underwater applications. There are also a lot of companies that make housings. There is a listing here at http://ocean-innovations.net/

Deep sea power and light has a free pressure vessel calculator if you want to make your own: http://www.deepsea.com/services/under-pressure-upwin/

 


(Harold Scadden) #7

Then there is the nasty thing called making the housing watertight. I have seen the calculator … actually Rusty told me about it. I know about Falmat … used some of their cable on a job for the Navy. Fiber Optic cables … fabricate those at work too.

You still have a long laundry list of issues that you are going to have to deal with. On your quest to go for the big dive, I would take baby steps unless you have a deep pocket book or you are going to bring up a lot of flooded units or waste a ton of money on things like Fiber Optic cable that you still need to terminate correctly … then you need the electronics to send / receive the signals so in the end, you are going to have to face the reality of your $8000.00 dollar unit cost is going to shift decimal places.

Either way, good luck.