How to electrically release a buoy ?

[Externet]

Hello all.
Am after suggestions; A buoy held at the bottom by a cord. A solenoid or servo mechanism has to release the buoy to the surface when a signal is received.
Where to look for proper waterproof parts, or how would you do it ?

This is not about the transmission/reception of the command signal; only about a mechanism that would/could release the cord from the bottom when energized by its battery, (that also powers a signal receiver).

Bottomanchorpoint------------------------------------------------------------------------cordhelddown-------buoy

When the cord ---------- is released, the buoy will surface.

 

[lowviz]

As I see it, the problem is with cleanly releasing a very strong upward force using a very weak actuating force.

Does this fit into your design? 100mm Pelican Hook & Eye with Quick Release Link Stainless Steel 316 Marine Boat | eBay

Just to be explicit, on the same page see: 87mm SWIVEL SNAP SHACKLES AISI 316 STAINLESS Chandlery | eBay

 

[KeithG]

You need to provide more information.

What amount of battery power will be available?
What amount of tension will the buoy exert on the release device?
What type of currents are expected?
How large / surface area of the buoy?
Is the buoy free floating or is it to remain tethered after release?
How deep is the mooring point (which i assume is where your release gizmo needs to go).
What is the required life cycle of the battery system?

 

[KeithG]

As I see it, the problem is with cleanly releasing a very strong upward force using a very weak actuating force.

Does this fit into your design? 100mm Pelican Hook & Eye with Quick Release Link Stainless Steel 316 Marine Boat | eBay

Just to be explicit, on the same page see: 87mm SWIVEL SNAP SHACKLES AISI 316 STAINLESS Chandlery | eBay

I was making the assumption that you would need to engineer the buoy to have minimal buoyancy at release depth since normal release mechanisms will not work if there is a high force on them. i was also worried about the (sideways) effect of current.

BUT: you have reminded me that Mythbusters used some sort of quick release that worked under high loads to drop heavy objects from heights. Maybe look them up!

 

[Diver0001]

Hello all.
Am after suggestions; A buoy held at the bottom by a cord. A solenoid or servo mechanism has to release the buoy to the surface when a signal is received.
Where to look for proper waterproof parts, or how would you do it ?

This is not about the transmission/reception of the command signal; only about a mechanism that would/could release the cord from the bottom when energized by its battery, (that also powers a signal receiver).

Bottomanchorpoint------------------------------------------------------------------------cordhelddown-------buoy

When the cord ---------- is released, the buoy will surface.

How long does it need to be held in place?

R..

 

[cool_hardware52]

Explosive bolts. Or.......

Inflate or displace water instead of conventional release.

"Triggers" are always tricky to design. You want a mech that is 100% secure, can resist large forces, but will fire with 100% reliability.

If this was my job and it had to be electrically actuated I'd consider a motor turning a screw that withdraws a pin from a shackle. The motion of the pin is perpendicular to the load. That helps, but does not entirely solve the force issues.

Good luck,

Tobin

 

[KeithG]

Explosive bolts. Or.......

Inflate or displace water instead of conventional release.

"Triggers" are always tricky to design. You want a mech that is 100% secure, can resist large forces, but will fire with 100% reliability.

If this was my job and it had to be electrically actuated I'd consider a motor turning a screw that withdraws a pin from a shackle. The motion of the pin is perpendicular to the load. That helps, but does not entirely solve the force issues.

Good luck,

Tobin

explosives - YES!

 

[Diver0001]

Really the easiest way to do it would be to employ an electromagnet. Turn off the power via a radio controlled switch and the buoy goes to the surface. No moving parts, no need to apply force to anything while everything is floating around underwater and even a small electromagnet can be surprisingly powerful.

The limitation would be the burn time of the battery because if the battery runs out then the magnet will turn off. That's the reason I asked how long the buoy needed to stay anchored.

R..

 

[KeithG]

Really the easiest way to do it would be to employ an electromagnet. Turn off the power via a radio controlled switch and the buoy goes to the surface. No moving parts, no need to apply force to anything while everything is floating around underwater and even a small electromagnet can be surprisingly powerful.

The limitation would be the burn time of the battery because if the battery runs out then the magnet will turn off. That's the reason I asked how long the buoy needed to stay anchored.

R..

Minutes? Or months?

 

[herman]

If you are thinking of using radio signals to control it....basically forget it. RF does not work well under water. Your controller will have to be either wireline or fiber to be dependable.