Out of curiosity, what happens when a model sub or a real one reaches that so-called crush depth? Does the seals slowly give and the sub fills w/ water or does it really dramatically implode like in that scence in "Abyss" where the minisub falls off the edge of the continetal shelf.

Id guess the first one. But thats just a guess. Movies like to blow stuff up. Like cars for instance. How many car crash aftermaths have you seen where the car has blown up? Doesnt happen very often.

Walley club subs taken down to 30+ feet have had the seals on motors give way, hoses collapse and the receiver seal pentrated. Also, there is a point that the styrofoam compresses to the point that the sub begins the "depth spiral". I know of a few that have experienced this.

yeah, sadly there is no dramatic implosion (although that IS what happens in real life)

usaually the seals areound the radio gear give way first, then the battery compartment

ive lost one wally world sub entirely to a crush depth, and ive recovered many others whove suffered badly

Wow, who took their Wally sub down to 30+ feet?

I don't seal the wiring tubes, so I always find water inside--and I know it seeps next into the radio-receiver "black box" and motors. I've probably lost more than one because, after leakage and some crushage of the buoyancy material, the sub got too heavy and couldn't come back up.

Anyway, that's how plastic RC subs sink. My sub-vet friend told me on manned steel subs you can see the hull caves in between the frame ribs; on new subs it happens until the hull is "set."

I guess it would vary--depending on the design of your sub--where water pressure would start bursting hull fittings or rupture the hull. I would think the implosion is less dramatic than the movies, but indeed air should bubble out of the broken hull in at least one place. With watertight doors shut, then I would think the ruptures might happen compartment-by-compartment, either puncturing the hull in multiple places and/or deforming bulkheads until pressure was equalized throughout.

Thirty foot depths have been possible because of people with test tanks at their companies. They used the transmitter off to the side so range was not an issue.

Use GE Silicone II RTV on your hoses..all the way around them and you won't have any problem with water in the hoses. You need to do that with motors and the receiver also on all seams...all around. If your going below 20 feet, you need to pull the hoses off and silicone on the INSIDE of the hoses also.

Below 20 feet or so most have said bye, bye to their walley sub as hoses began to pop off and seals burst....

Hey guys,

Isn't there a saying that goes "a good captian goes down with his ship."
If he was a good captian his ship wouldn't go down at all. As for dramatic
explosions, you would need explosive torpidoes and if you did and if the front compartment
imploded,BAM, theres goes a dramatic explosion along with your $2000 submerine.
Talk about depressing.

_________________________
Uh-Oh, Incoming!

These subs routinely dive to 20-30 ft and possibly more. Propulsion is from bilge pumps which are apparently sealed very well. Electrics are well sealed with only wire protruding.

http://www.youtube.com/watch?v=ntKT1araF3U



http://www.youtube.com/watch?v=pAZyL...e=user&search=


But I don't know crush depth?

Crush Depth

ive never owned/operated an RC or real sub but that phrase still makes me shudder

in real metal subs, basically the Weight of all the water literally CRUSHES the hull, (hence the name "Crush depth") pops hoses, bursts pipes e.t.c. But on RC subs its the depth when the pressure of the water outside is too much for the seals to take and so they burst or leak, if you are lucky you can retrive the sub before it takes on too much water and becomes too heavy to surface, but most other times, the sub just sinks because of all the water.

guys, sea pressure is somewhere around 50psi/inch per 100 ft when submerged (depending on salinity, temperature and all of that crap) an actual submarine will implode (from what I understand, I haven't experienced the implosion part just the crush depth). Typically you have test depth which is a safe normal operating depth, then "crush" depth, this is where the boat should implode, I know it's a wild ride when you go that deep. Seeing how the boat needs to contract and expand due to sea pressure, everything is built so it is floating, the deck plates, and everythign mounted to them. As you go deeper, you hear creaks and pops, but when really deep these start to get to be pretty huge and can scare the **** right out of you.. it's definitely a fun ride...

and seeing how crush depth is more of a design number, the boats usually can exceed this depth a bit (I kinda missed ordered depth one time and found out)

as for the real thing, you'd get shaft seals leaking (more than usual) and everything else that penetrates the hull would start coming loose and leaking, the flooding would pretty much take care of the rest, it would be a very quick ride from that point to the implosion point I would think...

thanks for the insight Did you miss ordered depth big-time, or just a little ?

Pardon me if I repost a story from a friend who was a sub vet:

He was sleeping in his bunk when awakened by a big down angle.

The groans of the hull grew louder. Off-duty, he and his shipmates had the luxury to picture how the sea might kill them in the next five minutes. They could do nothing but wait as the ship plummeted. Vern remembered the tension.

A locker next to Vern's head, its walls deformed against the straining pressure hull, blew its door--POW !

Obviously they came back up--but the way Vern told the story, he must have thought he'd died that instant.

Actually in the real subs is there is a short term leaking issue....then the depth actually tightens the hull and fitting areas until the leaking stops. Next things happen rather rapidly...imagine standing on a soda can, It will support your weight, and all will be fine....right up until something very small deforms that can, compromising its structural integrity.....CRUNCH!

Kind of the same principal....approaching crush depth puts strain on the entire exterior surface of the sub EVENLY but all it takes is one small part to buckle...and game over.

I myself have never experienced this of course, but during the course of my Military career I had the chance to hop a few sub rides, extracting from one is great fun, and met a few sub capt....thats how they explained it to me.


Recon

Actually yes there is a crushing depth it was shown on a either mititary or discovery channel. It was showing how ribs on a cigar shaped hull greatly increases its power. they had a pressure chamber and maxed them out. The scale cigar shapes crushed like tincans in miliseconds. Its jsut snapped in less than a blink of an eye it was very neat.

well...

If you know the internal preasure of the air inside the
sub and the amount of stress the hull can take, and add them together plus
6 feet you should have a pretty good "safe depth" number.