Mini scuba tanks instead of escape hatches?

[Boatguy30]

You loose whatever airlock you have with an escape hatch to the level of the highest/lowest point. That probably 10-15" of further sinking.

And is this the Poseidon adventure? Take a few breaths from the airlock in the hulls and swim out.

A proper cat, which ironically had a history of turtle. Is the Chris White Atlantic series. They have an escape into! The hull in one bow. Escape pod. No doubt Elon Musk's cat will have this feature.

[Siberian Sea]

Originally Posted by Rucksta

I have the cheap Chinese item with the pump.

Lubricate the pump with virgin olive oil.
It is important not to introduce any hydrocarbons into the breathing mix.
I've plumbed an activated charcoal filter to the fill line.
The filter sits in an aluminium (pressure) housing with a condensate reservoir and drain.

The air quality is good for shallow work.

I have a tether so I can't drop it bite fails.
Prop rudder & keel on first fill.
Assistant pumps while in water person does the waterline.
Second fill take care of the rest
Consider the effect of disorientation when you wake @ 02:30 to a flooded hull and have to locate & operate breathing apparatus then negotiate a debris field to exit in open water.

Vegetable oils like olive oil are hydrocarbon and unfortunately have a very low flash point. Compressors get hot and with each stroke of the pistions a small amount of this oil passes the rings and is burnt in the cylinders. The result is formation of carbon monoxide and your filters cannot remove this. You should never use this oil and it would behoove you to go to a scuba shop and buy real dive compressor oil. Of course you should have training and be certified before you use scuba or surface supply diving gear.

[Shammi]

Originally Posted by Thetis

Our newly bought (second hand) Schionning does not have any escape hatches and we want to avoid building them in. We are considering the purchase of small scuba tanks, 0.5 or 1 l, to be used in an emergency situation (boat upside down and you need to escape out of one of the hulls). They could also be used for a quick inspection dive. Is there anybody out there who can share his/her experience with one of these tanks? Plus: There are some comparatively cheap Chinese ones on the market, which come with a manual pump. We cannot imagine that this will work. Again: Can you share your experience?

This sounds like an EXTREMELY RISKY WORK AROUND. I wouldn't count on any part of this system to work when needed.

[Sparx]

Great discussion.

I am thinking between the location of the companion ways, the foam core hull construction, and the isolated fore and aft lockers in each hull and the bridge deck that my cat is highly viable inverted. No way would I add escape hatches near the waterline. Any spare air device seems to add complexity to an already strenuous situation. I totally agree with heading for the forward overhead hatch (now down) and swimming out. I hope to never have this situation occur, but if it did I want to keep the plan simple.

I think I will drill this scenario with the crew in preparation for offshore passage. I am thinking have people work their way to the hatch and open it with eyes closed would be a good start. The drill will also include people singing out when they get to the surface and regularly afterwards so we can keep track of heads during the process. I will also continue to insist that all portlights, locker, and bulkhead doors remain secured in the closed position while underway. Our practice is also to keep gear stowed and cabinet doors latched when underway. While I doubt all the cabinet latches will hold in a violent roll over, doing what we can to keep things tidy will minimize distractions from loose gear when trouble arises.

Jacklines for the inverted trampoline seem a great idea. Certainly very easy to rig on my boat.

[Nani Kai]

Wow. Where to start?

A64pilot and others cite THE most important aspect of having an emergency compressed air source as part of your self rescue plan: practice, practice, practice.

Secondly, the danger of holding your breath on compressed air and making a panic ascent is real and is addressed in another post I recently made. No need to repeat here.

I maintain strongly that the safest way for a non-diver to get out of a submerged vessel is to practice holding your breath, have a clear mental picture of your exit path from every location down below and have a light and a mask readily available in every berth.

The major drawback with an "all in one" emergency air bottle is that you must hold it with one hand. The second drawback is the very limited air supply. Adrenaline rush alone will make an inexperienced user burn through the air very, very quickly. Add positive buoyancy struggles, limited visibility and the boat misbehaving in high seas and that "5 minutes of air" rapidly becomes an illusion.

Worse case scenario: you are in your berth and the catamaran turtles. You have no fins or weight belt on and down is the way out. You have to overcome your natural buoyancy to get out and the best way to do this is to pull yourself down and along. Easy to do with two hands, much more difficult with one.

Visibility is the next big problem and without a mask the disorientation factor is huge.

In order of importance this is the escape equipment I would have in each berth: 1) an underwater light 2) a mask 3) a pair of fins

If an emergency air source was part of my plan I would have two. One in the salon at the top of the stairs on each hull. This would allow anyone below to pull themselves down to the air source using both hands, remove it from its holder, take a breath of air (or several) and then exit through the salon. This scenario makes an entire boat load of assumptions, but the main point is effective, safe use of an emergency air source. I would also make sure everyone on board was familiar with the use of the air source, preferably underwater.

Lastly, every catamaran I've sailed on, regardless of manufacturer, already HAS an escape hatch in every berth. It's right over head when you're lying in the bunk. Yes, I mean the deck hatch. When you're turtled it's right below your feet, much closer and shallower than the salon door and far less difficult to reach. Turn on your light, put on your mask, reach down to your feet, open the hatch and swim out. Am I missing something here?

btw, thanks to the OP for starting this discussion. I feel fairly confident that I could find my way out of the boat in an emergency situation by holding my breath, even in the dark. But why not make it easier? I will now make sure there is a light, mask and fins in each berth.

I feel safer already.

[a64pilot]

You don’t need to hold a spare air bottle, we never did. You do however have to bite the mouthpiece a little bit.
I’m astonished by the number of people that think breathing through a regulator is a complicated procedure.
But if your not comfortable with the idea, then adopting it is a bad idea. You need enough training / experience so that your comfortable.
Personally a spare air bottle would be comforting to me, as I know it would give me a few minutes to work myself out of an entrapment situation while underwater. Many have died diving by panicking when trapped by a simple line etc.
Ones of the first things you learn diving an overhead environment is that there is only one emergency, if you can breathe, there is no emergency, you have time to think your way out of a situation, if you can’t breathe, then you have an emergency..

[riki]

Personally i think it's a good idea. But that said, i would not put my life into a knock off garbage grabbed on aliexpress

[sparrowhawk1]

https://youtu.be/pZYWO0ylFoQ

This shows the impracticality of hand pumping a small tank up.

[captlloyd]

Originally Posted by sparrowhawk1

https://youtu.be/pZYWO0ylFoQ

This shows the impracticality of hand pumping a small tank up.

Well yes, if you are expecting to do some real diving. But we are talking about a escape supply that really should only require less than two minutes supply of air. Personally I wouldn’t need any tank and I am 75 years old. But you are comparing apples and oranges.

[a64pilot]

Originally Posted by riki

Personally i think it's a good idea. But that said, i would not put my life into a knock off garbage grabbed on aliexpress

I think I had rather have just a tank and feather the valve than go with what your describing.
It is after all a life support system, and needs to be sourced and treated as such.
I’m sure we could all swim out, or hope so anyhow, the point of an emergency air supply is to buy time in the event of your belt catching on the hatch on the way out or getting tangled in line. Who knows where the sails are, apparently a big deal about parachuting into water is being trapped under the chute, a main sail or jib could present problems on exiting? Or if there were others I’d like to think I would position myself if there were room at the hatch to ensure others got out, or maybe just outside of it. Some cruise with kids as an example or us, we have a little dog that I’d like to ensure he got out. It just buys time is all.
But if your not comfortable and know how to breathe compressed air underwater, maybe you shouldn’t have one.
I’ve heard the same about fire extinguishers, if you don’t know what your doing, maybe its best that you just get out, without training maybe someone would put the fire between them and the exit and try to fight it.
You should get training or education on pretty much anything, especially if it’s considered a life saving device, even life vests etc.

[Rorzech]

Originally Posted by a64pilot

I flew the AH-64 over the Yellow Sea, we carried “HEEDS” bottles on the left side of our survival vests and of course trained with them, HEEDS is of course an acronym, it stands for Helicopter Emergency Egress Device something, it’s been twenty years so I forgot.
Anyway these HEEDS bottles are nothing more than what Scuba divers call spare air, they are widely available, and you should train with them and they are refillable just like a Scuba tank.
Google found the HEEDS bottle, it’s just a spare air, don’t waste your money on a helicopter price https://www.aviationsurvival.com/-HE...e-17_p_35.html
There are a few differences with them over regular diving, to begin with nothing covers your nose, normally a mask does of course, but without a mask water gets in your nose when you breathe and that takes some getting used to.
Then of course you cannot have an auto inflating life vest or a regular buoyant one as it would just pin you to the top of the boat.

The Spare air bottle should give you about 5 min of air at very shallow depths and 5 min is a very long time. A major problem with suddenly being flipped over in a helicopter and I assume a boat is disorientation, we were trained to keep our left hand attached to the hand hold and use that as a reference to where you are, many People in training in the Dunker in NAS Jax where we received our initial training would head the wrong way and further trap themselves.
After Retirement I started cave diving and learned some more things there.

If were to have a Cat I’d want a couple of spare air bottles mounted in an obvious location, but I’d also want a light, just a decent dive flashlight would be fine, and a thin line that would lead me to the way out, this line could be attached to the roof so it would be out of the way which would of course become the floor. With just a little training a line can really be calming and ensure your heading the right way.

In cave diving a guy named Forrest Wilson invented the line arrow, it’s just a plastic triangle that attaches to the line and of course always points the way out, before the line arrow there were some deaths where people got confused and went deeper into the cave thinking they were headed out.
https://www.diverite.com/products/reels/line-arrow/
Forrest is an old guy now but still dives or was when I stopped anyway.

If you go with a spare air bottle, you need to at least become accustomed to breathing one underwater, and it can be the middle of the night of course. I would be very comfortable with a spare air myself with a light and a line.

Why does everyone think the cat is going to sink when it's upside down. A person should take the time to get their bearings then make a good plan that is made to coincide with your circumstances . There is probably a storm or big waves outside. You should stay inside because you are not going to sink right away. You can stay inside until it light out and is save to go out, You should make a tether to keep you to the boat and have a knife to cut it incase of emergency. If you relax and take a half an hour to think of a good plan you won't need any goofy tanks that can kill you in a minute. Just use your head.

[riki]

Originally Posted by a64pilot

I think I had rather have just a tank and feather the valve than go with what your describing.
It is after all a life support system, and needs to be sourced and treated as such.
I’m sure we could all swim out, or hope so anyhow, the point of an emergency air supply is to buy time in the event of your belt catching on the hatch on the way out or getting tangled in line. Who knows where the sails are, apparently a big deal about parachuting into water is being trapped under the chute, a main sail or jib could present problems on exiting? Or if there were others I’d like to think I would position myself if there were room at the hatch to ensure others got out, or maybe just outside of it. Some cruise with kids as an example or us, we have a little dog that I’d like to ensure he got out. It just buys time is all.
But if your not comfortable and know how to breathe compressed air underwater, maybe you shouldn’t have one.
I’ve heard the same about fire extinguishers, if you don’t know what your doing, maybe its best that you just get out, without training maybe someone would put the fire between them and the exit and try to fight it.
You should get training or education on pretty much anything, especially if it’s considered a life saving device, even life vests etc.

Buy time, thats it. This is why i think that it's a good idea to have one of these small bottles in each cabin used. 2 minutes autonomy should be enough to swim out. And i think that it's probably even a better solution than an escape hatch, specially in darkness and panic situation having to deal with the variables you describe.

[riki]

Originally Posted by Rorzech

Why does everyone think the cat is going to sink when it's upside down. A person should take the time to get their bearings then make a good plan that is made to coincide with your circumstances . There is probably a storm or big waves outside. You should stay inside because you are not going to sink right away. You can stay inside until it light out and is save to go out, You should make a tether to keep you to the boat and have a knife to cut it incase of emergency. If you relax and take a half an hour to think of a good plan you won't need any goofy tanks that can kill you in a minute. Just use your head.

And what if while you're taking your time you find yourself 30 meters deeper?

[fxykty]

Originally Posted by Rorzech

Why does everyone think the cat is going to sink when it's upside down. A person should take the time to get their bearings then make a good plan that is made to coincide with your circumstances . There is probably a storm or big waves outside. You should stay inside because you are not going to sink right away. You can stay inside until it light out and is save to go out, You should make a tether to keep you to the boat and have a knife to cut it incase of emergency. If you relax and take a half an hour to think of a good plan you won't need any goofy tanks that can kill you in a minute. Just use your head.

This.

We’re not talking about fragile racing catamarans and even overloaded cruising cats will float for a long time due to trapped air. There’s lots of time available and absolutely no need to immediately exit the hull you’re in. Fire is the obvious exception but then likely you’re not capsized.

Exit via the salon is a no-go, unless you’re already in the salon. But it means exiting under the bimini top and whatever’s left of the canvas, mainsail and rig - too many chances of getting caught by something.

You may even open an escape hatch to let someone outside in. Inside is safer than outside in the immediate aftermath of a capsize.

Unless your boat has a purpose built and maintained and separated inverted room, long term it’s not going to be so nice inside the hulls. Best position to wait for rescue is in a liferaft tethered to the underside of the bridgedeck, adjacent to the escape hatches. The hatches can be used to gather supplies - grab bags with water and food and rescue gear should be secured near the escape hatches.

[Captn_Black]

I don't see how they would help in the event of an engine or galley fire...