SSS- Simple Submarine Systems

A new thread focusing on the adaptation and use of simple, low cost, off the shelf technologies for simple low cost civilian submarines.

 

Simple low cost submarine....

Fins, mask, Snorkel
Fins, mask, snorkel, battery, motor
Fins, mask, snorkel, battery, motor, Air tank, regulator

How simple you want it....

wet or dry sub

what depth.

Once your talking dry sub - simple starts going away quickly.

 

Wow that was quick!

I respectfully,
and with experiance on the subject, beg to differ.

Once upon a time I was in charge of doing the impossible with less.

I did it!

After I did it a few times in a row I was in charge and realized that complexity is the fools friend.

Simplicity, is not the result of ignoring the problems but instead adressing them in a way that a single component adresses many problems in an eligant way.

To the fool it looks too simple. To the enligtened it is as elegant as a Rembrant. The more you look at it the more you understand and apreaciate the mastery of the artist.

You find them in their office in the lotus possition chanting

"KISS"... "KISS"... "KISS"

while they design in real time in their head that which would take a year to enter into a CAD system!

This is especially true when you are dealing with the need for life critical systems and redundancy. Simple designs are the only ones that can be validated! Complexity raises the cost exponetially in life critical systems.

This leads the artist to minimize the life critical systems and maximize the "Inherant Safety" e.g. fail safe capability of a design.

In a sub that Means managing:

0) Self Rescue (Automatic & Reliable)
1) Surface = Safety (Positive Boyancy...)
2) Breathable Air (Air Quality, Flooding...)

As you might suspect keeping these systems simple might also impose limitations on the capabilities of a sub using them. that's where FFF - Form Fits Function comes in.

No reason to use a technology designed to go under the polar ice caps if all you want to do is dive under rough seas for a few hours.

 

A lot of information’s here:

http://www.psubs.org

 

Dry sub, wet self rescure, Just like a boat

"Inherant Positive Boyancy" IPB is probably the most important part of "self rescue" in any submersible wet or dry.

If boyancy fails due to flooding or entrapment "self rescue = wet rescue". At depths below 120' this is not practical due to surface rate limits imposed by the bends. Simple hoods have proven more than adequate for self rescue if undertaken "before" the individual is exposed to prolonged (> 15 min) > 1 ATM breathing environments before using a hood to surface. Only military and research vessils have any business down that low because there is just nothing down that low worth the massive increase in risk!

Such a system means that the sub has to be designed to prevent diving below that depth intentionaly, accidentaly or during a failure!

Designing a sub that must power it's way down below 40' due to IPB "Inherant Positive Boyancy" means that if the power fails the sub floats back to the surface. An automatic cut out prevents it from "powering" down below 100'. Add a simple preasure activated automatic droppable ballast system and you have simple, redundant IPB. even if you are entrapped you remain above the self rescue depth of 120'.

A concrete sub simplifies this because it's volume and therefore it's boyancy coeficient (depth corrected) does not change as it dives since the water outside is not changing density significantly as it dives or surfaces.

The harder case is the negative boyancy entrapment. e.g. something is decreasing your IPB. The most common are nets and flooding. free floating nets that are themselvs too heavy to float but have entrapped you while above your self rescue depth are rare but lets deal with them any way as we deal with the most likely threat of flooding (Loss of IPB).

Loss of IPB due to Flooding is the real killer in any kind of sub, Military, Research and Civilian (many examples) because just dropping some ballast is not going to do any good in a flooded sub that weighs more than the water arround it! You have to maintain the boyancy in all concievable scenario or you have to get out before the flooding sinks you below the self rescue depth.

belive it or not most non depthcharge flooding "accidents" happen very close to the surface due to snorkle malfunction and or collision with surface ships. unfortunatly a thin skinned steel sub is at a real disadvantage in a collision because the more massive vehicle almost always ruptures the preasure hull so masivly that the sub sinks in under a minute! It's probable because of the compressive strength of concrete that a collision would result in leaks instead of ruptures and this is something that you can design the hull strength for. it will in fact probably be the driving criteria over the depth design limit of < 300'.

So the question is what simple design criteria and or automatic system could use to maintain IPB long enoghf to self rescue following a collision. Some simple concepts could be based on trapping air by making sure there are no "portals or throughhulls" above the bottom 50% of the hull. Even the fly bridge and snorkle would have to be accessed from a tube that terminated below the 50% point in case of a failure. The result is a trapped air bubble that if sized propperly with the droppable emergency ballast is large enoghf to maintain IPB!

If you add automatic addition of preasurized air to make up for the small hull fracture leaks (which occuredt at the surface) you can automatically keep that IPB for a period of time that allows you to self rescue at the surface.

There will probably pe people hurt just like in any surface colision but you have minimized the likly hood of a "DEEP" self rescue following a surface incident which are the common killers in military and research vessels.

In the spirit of colective improvement, how about throwing in a few enhancements along those lines MyDauphine?

 

I have looked it over quite well

I have looked it over quite well but they are not typically focused on simple dry private subs of the scale of 200T for pleasure. If you look there you might see a few posts on air handling systems that look familiar. LOL

Very little focuse on surface navigation of subs, very little focus on collision avoidance and recovery, very little Yacht related sub issues. Honestly i have no problem cross posting SSS there. or moving it there is boatdesign.net feels that these discussion would better serve the comunity on another site.

But that begs the question of why concrete hulls are here> LOL

 

Underwater scooter
http://swissmiss.typepad.com/photos/uncategorized/scubadoosideshot.jpg

 

what if your hit by a 90000 ton tanker with 200"' of draft would ipb handle that?

 

Great little device for exploring a reef 'With" the sharks (nasties).


Note the yellow cord attaching them to the surface. I heard tell that the umbilicle(s) can get tangled when you have a couple of the in close proximity.

So they are not always considered 'Independant'.

A great example for FFF - Form Fits Function. their form is simple for their function!

 

Is that 200" or 200' LOL?

The last time I looked surface vessils did not survive that!

But the answere is yes, the hull would likley maintain positive boyancy (for a time) but the forces involved would (like with a small surface ship) likely kill the occupants due to blunt trauma as the sub bounced off the hull or put a serious dent in it.


I saw a video of a sport fisher that was hit by a tanker and pushed 30' under the hull where it broke up. No survivors! Moral of the story. Stay away from the big guys by using an AIS reciever. All large >300 ton vessil are required to transmit their location, speed and course while at sea and frequently while at dock!

Great post, can you add some context on the design survivability requirements of small craft and yacht?

 

Simple IPB & Self Rescue

I will try to describe here one possible SSS IPB and self rescue solution of many that come to mind. There are probably better and I hope we will discover them together.

Maintain IPB

1) Limit Flooding to < 50%

a) No Through hulls terminated above 40% of hull height (Simple Passive)
- No snorkles, windows, shafts or exits above 40%

b) Hull designed to leak (crack) not fail in a specified collision (Simple Passive)
- Concrete, Inflatable bag... (probably not steel!)
- Simple automatic compressed air makup system that replaces
slowly leaking air to maintain >50% trapped air volume.

c) Droppable ballast that guarentees positive boyancy at 60% flooding (Simple Passive / mechanical activation)
- automatic when flooding over 10% detected
- automatic when depth > 120' detected

d) Permanent (non Droppable) low ballast (Simple Passive)
- prevents high for aft angles and maintains 50% airbubble
at top of sub not one end or the other.
- This also requires that the hatch tube be at the relative
center fore and aft.

Theoretically these simple inherantly reliable (Passive) systems would automatically surface the sub if you opened the hatch at up to 150' or a surface colision resulting in gradual flooding!

Self Rescue
1) Top hatch terminating below 50% Air bubble allows open hatch self rescue!

a) No complex lock out proceedures (training) or delays which result in
prolonged exposure to ambient preasure (if entraped below 40')
and possibly the bends.

b) First person dons their rescue hood, opens the hatch, and pushes
out the solas life raft.

c) Subsequent people don their escape hood, make a shallow dive
under the hatch extension and follow the life raft line up to the
surface and the safety of the raft. A simple caribiener will keep
the young and scared from loosing contact with the rope.

d) An audio device built into the each escape hood reminds people to
"Breath deeply and do not hold your breath". It can even provide
a changing breathing cadence based on the depth / preasure.

e) At the surface the first person out helps the others out of their hood
and into the life raft. The survival rafts automatic Ebirb has already
notified the athorities of the rafts automatic deployment and location.

f) Now it's up to the captain to make that faitful decision to
abondon ship or stay and save his vessil. Only a captain at sea
can make that decision! But only after his responsibility to his
passangers and crews safety are met!

2) Waterproof / preasure proof emergency lighting is a must to enable
effective self rescue in an otherwise dark submerged hull.

3) Rescue hoods can be designed to double as fire hoods to provide safe
breathable air in the event of a fire. Fires in a confined space are a very
serious danger. Much more likley than sinking or collision.
a) Cooking should be isolated from the main air space
b) Electrical systems should be automaticaly shut down if smoke is
detected.
c) Fire alarms, detectors and hoods should be in every compartment.
d) All materials should be non flamable and or self extinguishing.
e) Avoide PVC plastics due to deadly clorine emissions durring a fire.


All sea going vessels religh primarily on passive design safety as their
primary means of ensuring (to a high degree of certainty) their safe use
by mere humans! LOL

 

Oh, don’t get me wrong, I wasn’t trying to suggest moving to Personal Sub’s site. There is more then enough interest for submarines on the Boat Design Forum. For many of us subs are maybe not primary focus of our water related addictions, (cruising sailboats for me), but we are still interested.

PSUBS is indeed primarily oriented towards smaller subs, but still, there are many interesting information’s there. For example book about acrylics for view ports and R. F. Busby’s book about manned submersibles, forum, many interesting projects, ec.t.

 

I agree Milan!

Psubs has some great pointers to "existing" reference material but their actual posts are a bit limited if you look at navigation, air handling, self rescue, emergency escape, propulsion and a wide range of other "Critical Systems".

There are obvious experts there, but they choose not to share for some reason. Possibly dreams of turning their passion into their payroll?

I hope to focus SSS on people who feel free to 'give' their "solutions" as readily as they give their "concerns".

This has worked extreemly well in the open source area and psubs is trying to make a go of it for a small open source sub.

I see SSS as open source 'systems' for subs of any size since simple systems tend to scale very well.

 

Epipelagic zone Subs (200 m, 650')

The systems needed for 0-120' are significantly simpler than systems that operate effectivly below that depth due to the bend challenges of self rescue below 120'. This adds greatly to the complexity of ensuring safety.

Likewise subs operating below 650' have additional safty issues that significantly complicate or limit the design.

Personally I do not see any practical reason other than tankers and huricanes that would make me want to spend any significant amount of time below 60'. certainly no reason to risk my life below ambiant self rescue limits of 120'.

Most of my posts will initially be focused arround exploiting the inherant safety and simplicity afforded above 120'.these limits.

Ambient rescue allows both self rescue via a hood and or simple non sealed rescue by scuba divers and ambiant subs. It also limits the tarpped air bubble needed to ensure boyancy durring accidental flooding.

 

Pan-am,
I have built many a boat the largest 70' - 75 ton. What do you figure the costs for your SSSubmarine ?