Tom Chalfant - Bronco Type XXIII

[redboat219]

Subculture,
Notice that the chirp interval is every 5 seconds, is this to conserve battery power?
I think it's hard to get a bead on those chirps at that rate. Wouldn't a 1-2 second ping be easier to locate?

[Kazzer]

.................................................. ..the LPB refused to run when commanded; the boat grounds and could not be dynamically driven to the surface.


M

Pure supposition on your part. No one can say the pump was the cause. Get the boat on land before making guesses.

[He Who Shall Not Be Named]

The boat went 'deep', past the point where the very small amount of built-in reserve buoyancy of the submerged boat is canceled by box-compression -- deeper and the boat is negatively buoyant; the LPB refused to run when commanded; the boat grounds and could not be dynamically driven to the surface.

Likely, during the recovery attempt at the transmitter -- working blind, the boat was driven outside the recovery diver's search pattern.

Game over.

****!

An emergency 'bail-out bottle', now in development as an optional retro-fit for SAS type SD's. This item recommended for deep-water operation. This emergency gas blow feature, activated only by fail-safe, would have saved this boat. Existing SD's have provisions to accept this retrofit with little effort.

Hind-sight is 20/20.


M

[Kazzer]

.......................... so you want a pinger that will carry on emitting for as long as possible.

Yes, I guess the recent mysterious loss of the Malaysian plane is a good example of battery loss causing problems. Seems a bit odd to me that no one could come up with a charger that replenishes the battery underwater. After all, there is enough electrolyte around the black box. Surely nickel/cad plates could be attached to the outside of the box?

[redboat219]

HWSNBN,
Any theory on how a faulty SAS pump would have sunk Tom's boat?

[redboat219]

Musical greetings cards might be a bit thirsty. You want a noise which is distinctive and that will cut through other sounds like fish, which can make a noise.

What can be more distinct than hearing "Happy Birthday to you" underwater? Lol

[He Who Shall Not Be Named]

Just to let you all know that me and Mike are following this thread with interest. Good stuff. Keep kicking this ball down court.

M

[Subculture]

Musical greetings cards might be a bit thirsty. You want a noise which is distinctive and that will cut through other sounds (like fish, which can make a noise), but which minimizes power consumption. If you're lucky and have divers on site, then you may only need a few hours of battery life. However often you have to wait a few days for something to be arranged, so you want a pinger that will carry on emitting for as long as possible.

[Subculture]

That's a very interesting idea. Do you have any diagrams? Is it a copyrighted thing? Anyone making therm for resale?

No copyright. Not available commercially as such. Dave Forrest in the AMS supplies programmed PIC chips for about £6, but that is to members only.

I believe the idea originated from modellers sometimes locating downed craft by the noise of their propellers. Clearly that will only work if the throttle is stuck on or if you still have radio range and power to your sub, but if the power is off or the batteries drained, you're stuffed.

Basically the hardware is a microcontroller (e.g. pic, atmel etc.) powered up with a couple of lithium button cells. The output from the microcontroller is hooked up to a piezo transducer, which is in turn bonded to the wall of a watertight housing so it resonates the enclosure and magnifies the output. The swooping ping which sounds about every 5 seconds decreases in frequency after several days to preserve battery life.

A couple of 3V CR2032 button cells are enough to keep the pinger working for several days I believe

They have a very high success rate in finding models, and are especially valuable when sailing murky or deep water.

I've recorded the ping sound below- much louder in water. You need an aquatic microphone and amplifier. Again these were self made, but you can build up a gadget with commercial items, not sure about the microphone itself, that you may still have to build, but it isn't a difficult item to construct.

[redboat219]

Diagrams for homemade hydrophones are readily availble online.
As for the pinger, here's a really cheap way, use the speaker and driver from musical greeting card.
For a waterproof enclosure you could place it inside a tic-tac case.

[Kazzer]

That's a very interesting idea. Do you have any diagrams? Is it a copyrighted thing? Anyone making therm for resale?

[Subculture]

Even with a ballast system that can provide plenty of up thrust on demand you can lose a boat. It can get caught in sub aquatic wildlife, have a catastrophic leak or even attract the attentions of an amorous pike.

Quite a few modellers here in the UK equip their boats with pingers. These are self powered discrete devices that give out a periodic swooping sound. Used in conjunction with an under water microphone it enables accurate location of your boat in the event of a sinking. They only cost a few pounds to build and the pinger can be moved from boat to boat.

[redboat219]

Time to initiate your own SUBSAFE program.

[trout]

I mentioned in the past, " keep the gas system" but all I got from you guy's is verbal abuse on how great the SAS system is. Serves you right!!! I must say also, That I'm sorry for your loss!

I do not remember giving you verbal abuse, but you were right in this case. Thank you for the condolences.

[trout]

Type XXIII Mark II will indeed have that. It is a great idea that you added the extra safety.