Using breathing aparatus instead of escape hatches?

[StuM]

Originally Posted by Cadence

Don't be below in weather conditions where you might turtle. I should think there would be enough captive air to get enough gulps to swim out? JMHO is escape hatches are a marketing thing?

They're a legal thing for EU boats under the RCD.

(And also a requirement under ISAF if you're competitive).

[AD28]

You might want to read accounts from folks who have experience:

http://www.amazon.com/Capsized-James.../dp/0061090905

The Spirit of Rose-Noelle: John Glennie: 9780449220825: Amazon.com: Books

[boatman61]

Originally Posted by a64pilot

Well, yes you really should let the Winter air out and put in Summer air if you want to get the best mileage. Winter air is denser.


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By best mileage I assume you mean more air.. is that not counter physics..
I thought one was advised to fill tyres when cold was to enable the correct pressure in the tyre as it expands when heated by the friction when it travelled.. logic being if you fill when hot the heat expanded air in the tyre will not allow sufficient fresh air into the tyre..
However if its to stop tanks exploding.. then I get it..

[a64pilot]

Ah, but Boatie, winter air is more dense, therefore heavier and carrying around excess weight cost fuel, so dump the old Winter air and put the lighter Summer air in

UH-60 helicopter had pressurized nitrogen in it's main spar of the rotor blades, this pressure was monitored by an indicator on the blade, get a cracked main spar, pressure leaks out and your altered prior to blade failure. Pretty smart I thought, but like everything it needs service every now and again.
So we have Crew Chief re-filling the blades with Nitrogen from a cylinder, cylinder has NITROGEN printed on it in BIG letters. Up walks this Lt. and the Lt asks "what are you doing", Crew Chief answers without missing a beat "Sir in this unit we fill the blades with Helium, we have found out that a helicopter who's blades are filled with Helium can lift significantly more cargo that one who's blades are filled with air.

Lt. being an Officer of course had to act as if he knew this and told the Crew Chief to carry on.

I had to ask the guy how could he look at himself in the mirror in the morning doing stuff like that

[ejlindahl]

Your crew chief would fit in well at my old fire dept. I miss working there.

[StuM]

> Winter air is denser.

No, you've got that backwards. Where Boatie is, average MSLP in lower in winter than in summer. That means that winter air is generally less dense.

If he keeps that less dense air in his tyres throughout the summer, his car will be lighter than if he put heavier summer air in the tyres. That reduced weight will improve fuel economy, reduce pollution and save the planet for our grandchildren.

[Cadence]

Originally Posted by StuM

> Winter air is denser.

No, you've got that backwards. Where Boatie is, average MSLP in lower in winter than in summer. That means that winter air is generally less dense.

If he keeps that less dense air in his tyres throughout the summer, his car will be lighter than if he put heavier summer air in the tyres. That reduced weight will improve fuel economy, reduce pollution and save the planet for our grandchildren.

Fill the tires with nitrogen and the breathing tank with nitrous oxide. The tires will last longer you will still drowned but won't care.

[Pete7]

The larger of the Spare Air cylinders has an internal volume of 0.44L I hope you don't mind us working in metric because the maths is so much easier.

0.44L x 200 bar (the maximum pressure) equals 88 litres of air.

Now all you need to know is what a panicking trapped sailor will breath. From 25 years of diving my normal breathing rate would be 20 litres per minute (LPM) x the depth in bars. At the end of the season in warm waters and good conditions down to 15 LPM. However, a novice or someone learning to dive can really breath hard and empty a dive cylinder surprisingly quickly.

So lets say a panicking sailor will be around 50 LPM . After all they will have had to find the Spare Air in an upside down Cat possibly flooded, without lights and all loose furniture, possessions plus things like batteries crashing about. The sailor could of course be out of breath and in oxygen debt when he finds the Spare Air. Any thoughts of controlled normal breathing just isn't going to happen unless they are an experienced diver. The sailor will breath fast and deep.

So at 50 LPM our sailor will have a minute and a half or so. Would I carry one? yes possibly, but they need to be easy to reach when the Cat is upside down and the inside has gone to rats. There is a risk of drowning whilst searching for the Spare Air rather than attempting an escape.

I only dive once or twice a year now, but do carry a 5L cylinder on board to clear a rope etc. Could I locate and assemble the regulator to the cylinder in the forepeak, turn it on and breath in an upside down mono in the dark under water, probably not. It would be better to just escape.

Pete

[a64pilot]

Depending on conditions of course a min and a half can be a long time, but I thought these things had rather large air pockets? I've heard of people spending extended times in an inverted Cat and had wondered myself if maybe in the type of weather it would take to turtle a cruising Cat if you wouldn't be better off inside, than outside?
My swimming SAC rate is .67 cu ft per min and deco .5 for the English version.


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[Pete7]

Originally Posted by a64pilot

My swimming SAC rate is .67 cu ft per min and deco .5 for the English version.

Ah, but you are a diver, diving a planned dive in suitable conditions.

[Cadence]

Originally Posted by a64pilot

Depending on conditions of course a min and a half can be a long time, but I thought these things had rather large air pockets? I've heard of people spending extended times in an inverted Cat and had wondered myself if maybe in the type of weather it would take to turtle a cruising Cat if you wouldn't be better off inside, than outside?
My swimming SAC rate is .67 cu ft per min and deco .5 for the English version.


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I'm probably a crotchety old bastard. If you can't swim well enough to find your way out through a companionway maybe you should not be sailing? A capsized boat will have an air pocket. Panic is probably someone's worst enemy.

[a64pilot]

I didn't doubt your numbers, just giving the English version of the SAC rate.
I'm sure in a ditching situation in a helicopter the HEEDS bottle was enough, I assume in an overturned Cat, you get in that air pocket til you decide you need to leave, and then the spare air wouldn't be a bad thing to have. I'm just guessing though, I don't have any Cat experience.
I'm still trying to decide if I should take tanks with us or not, I hate aluminum 80's is the only reason or I'd just rent. With steels I carry more air, with less tank weight and don't have any lead.
If you had full tanks on board and they were accessible well then you have I guess at least an hour.


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[Franziska]

Definetly a good product to have.

One other thought, on my boat there are no escape hatches, yet.
Definetly will fit some at one stage.
For now I have a combo of Dive Mask, ax and flashlight in each hull. Would be clearly good to add the emergency breather.

Just wondering though if officials might consider the ax a weapon when clearing in?
It#s mounted close to the steps towards the bridgedeck.

[boatman61]

Originally Posted by Cadence

I'm probably a crotchety old bastard. If you can't swim well enough to find your way out through a companionway maybe you should not be sailing? A capsized boat will have an air pocket. Panic is probably someone's worst enemy.

Obviously not that old.. for eons it was considered that non-swimmers make the best sailors.. their terror of the depths made sure they did things Right 1st Time..

[a64pilot]

Originally Posted by Franziska

Just wondering though if officials might consider the ax a weapon when clearing in?
It#s mounted close to the steps towards the bridgedeck.

Surely it's a tool, label the thing "escape Ax" and they may not even ask.