Thanks ! Iwas about ready to give up on this site. I don't understand Divemaster B'S attitude. that is why is probly a YMCA instructor he couldnt cut it as a PADI instructor. Sorry about the last remark he just brings it out in people. I always heard enginners could not pour pee out of a boot unless it had a faucet
Training Plaform?????
- Thread starter SCUBA1951
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SCUBA1951:
YMCA Scuba was around long before PADI. Its harder to become an instructor for the YMCA. While one PADI instructor can make another Instructor, in the Y program they hold an institute course once a year in Florida or Indiana(they alternate). Just because you pay for the institute dont mean youll become an instructor. So your comment about not cutting it as a PADI instructor......well......its really the other way around. Plus to become a YMCA instructor you dont have to buy the "brand" gear your Dive Shop instructor sells as a prerequisite. YMCA instructors are usually not attached to shops so they wont be sales pitching you on the specials of the week.
Three things you never argue.....Religion, Politics and Certification Agencies....Especially when its CERTIFICATION AGENCIES!
Bad Sea Monkey!
Capnsnott
Contributor
Ok, wow, another thread heading toward the shallow end.
Now, back to topic.
Anchor;
I think the easiest thing for you to do is to use one plastic 55 gal or 35 gal drum of the anchor. Drill 3/4" diamiter holes at four oposit places just below the thick rim of the drum. Use the chain repair links, or the screw together ones and put them in these holes. Run one thick rope through them and up to the platform. Cut a basketball sized hole in the top of it, put in enough sand to sink it, but not enough that you can't move it into position. When you get it where you want, either fill it with sand or cement. The sand can be dumped out later if you want to move it. I suggest using "tube sand" bags for the sand. You can drop them to the bottom and dump them into the drum. They weigh about 30#, so they aren't too heave to move under water. The other option is to have someone lower them down on a rope. If the one drum turns out to be too light, just add another later.
Platform;
Use 3" or 4" PVC pipe, Make the main frame out of this. You can use "T" fittings centered between the 90s of the corners and run one piece of pipe across the center. This gives you a small support for the flooring material. In each corner, drill a hole all of the way through from top to bottom. Run "Eye bolts" through from the top, this is where you will attach the float lines. You can seal the holes if you want to give the platform bouyancy. If you want a floor, use the "neon orange" nylon safety fencing material. It works great for stuff like this. You can wrap it around the platform and secure it underneath with zip ties.
If the platform is bouyant, you can tie it off to the anchor (temporarily) using nylon rope and it will stay put while you are rigging the floats. Don't tie it off solid to the anchor till you have the proper depth set on it. You may want to tie seperate loops onto the platform in a permenant way, then use good quality carabeeners to clip it to the anchor ropes.
Surface floats;
I suggest using 35# plastic drums. I think whatever you decide to use for sling needs to be protected on top from the sun. Nylon rope will work good, but the sun is going to eat it up.
My feelings it not to use netting on the deck, just have the tubing for people to "hang" on to. This makes them figure out their bouyancy a lot faster and keeps a bunch of weight off the entire system. It also promotes horizontle safety stops (if set at 15').
This is a combonation of platforms I have looked at over the years. It's what I would do if I was to do one.
Hal Wats has some with expanded steel for the flooring in his grotto, they are pretty heavy I bet. He uses one steel cable for the anchor line.
The platforms at the Blue Hole in New Mexico are made of PVC with the eye bolts and 5 gal. buckets with concrete in them.
Good luck.
Greg aka Doc.
PS,
Ignore the flames, boards are one of the few places people can try and feel superior without consequence. There are a lot of keyboard divers.....
Now, back to topic.
Anchor;
I think the easiest thing for you to do is to use one plastic 55 gal or 35 gal drum of the anchor. Drill 3/4" diamiter holes at four oposit places just below the thick rim of the drum. Use the chain repair links, or the screw together ones and put them in these holes. Run one thick rope through them and up to the platform. Cut a basketball sized hole in the top of it, put in enough sand to sink it, but not enough that you can't move it into position. When you get it where you want, either fill it with sand or cement. The sand can be dumped out later if you want to move it. I suggest using "tube sand" bags for the sand. You can drop them to the bottom and dump them into the drum. They weigh about 30#, so they aren't too heave to move under water. The other option is to have someone lower them down on a rope. If the one drum turns out to be too light, just add another later.
Platform;
Use 3" or 4" PVC pipe, Make the main frame out of this. You can use "T" fittings centered between the 90s of the corners and run one piece of pipe across the center. This gives you a small support for the flooring material. In each corner, drill a hole all of the way through from top to bottom. Run "Eye bolts" through from the top, this is where you will attach the float lines. You can seal the holes if you want to give the platform bouyancy. If you want a floor, use the "neon orange" nylon safety fencing material. It works great for stuff like this. You can wrap it around the platform and secure it underneath with zip ties.
If the platform is bouyant, you can tie it off to the anchor (temporarily) using nylon rope and it will stay put while you are rigging the floats. Don't tie it off solid to the anchor till you have the proper depth set on it. You may want to tie seperate loops onto the platform in a permenant way, then use good quality carabeeners to clip it to the anchor ropes.
Surface floats;
I suggest using 35# plastic drums. I think whatever you decide to use for sling needs to be protected on top from the sun. Nylon rope will work good, but the sun is going to eat it up.
My feelings it not to use netting on the deck, just have the tubing for people to "hang" on to. This makes them figure out their bouyancy a lot faster and keeps a bunch of weight off the entire system. It also promotes horizontle safety stops (if set at 15').
This is a combonation of platforms I have looked at over the years. It's what I would do if I was to do one.
Hal Wats has some with expanded steel for the flooring in his grotto, they are pretty heavy I bet. He uses one steel cable for the anchor line.
The platforms at the Blue Hole in New Mexico are made of PVC with the eye bolts and 5 gal. buckets with concrete in them.
Good luck.
Greg aka Doc.
PS,
Ignore the flames, boards are one of the few places people can try and feel superior without consequence. There are a lot of keyboard divers.....
One is a sunken steel storage container. Instructor types kneel their students on it's roof.
The other I "discovered" while mapping a local lake for my DM project - it's a piece of chain link fencing with the tubular frame. One edge rests on the mud slope, the outer 2 corners each rest on a 55 gal drum. Later inquiries revealed that yes, it had once been used to kneel students upon. When I found it, it had obviously not been used lately as evidenced by the abundance of fresh water sponges thriving on it.
The other I "discovered" while mapping a local lake for my DM project - it's a piece of chain link fencing with the tubular frame. One edge rests on the mud slope, the outer 2 corners each rest on a 55 gal drum. Later inquiries revealed that yes, it had once been used to kneel students upon. When I found it, it had obviously not been used lately as evidenced by the abundance of fresh water sponges thriving on it.
Capnsnott
Contributor
Thread hijacking on......
Gaaaaaa,
Thou saideth a badeth word.... KNEEL.......
oops, sorry personal flakeyness coming through.
Thread hijacking off.....
Yeah, Hal's were all steel too. Emagine one of them breaking loose above you while your sitting at 130'. I don't think the hole was big enough diamiter to get out of it's way down there.
Gaaaaaa,
Thou saideth a badeth word.... KNEEL.......
oops, sorry personal flakeyness coming through.
Thread hijacking off.....
Yeah, Hal's were all steel too. Emagine one of them breaking loose above you while your sitting at 130'. I don't think the hole was big enough diamiter to get out of it's way down there.
I don't understand why a kneeling platform is needed.
SCUBA1951:
Not really, if you know the buoyancy. I am making the following assumptions:
1) That the pressure inside the drum will be 1 ata or 14.7 psi.
2) That the drum is made of aluminum and weighs 50 pounds.
3) That this is going in freshwater.
First thing you will have to do is determine the bouyancy of the 55 gallon drums. 55 gallons converts to about 7.35 cubic feet. ( Gallons/7.48 )
Then using Archimedes Theory, we get the following info:
The internal volume of the cylinder is 7.35 / 15 * 14.7 = 7.2 cu ft
The cylinder is made of 50 lb of aluminium, (which has a density of 170 lb/cu ft).
The aluminium therefore has a volume of 50 / 170 = 0.29 cu ft, so the total volume is 7.2 + 0.29 = 7.49 cu ft.
The density of fresh water is 62.4 lb/cu ft, giving 7.49 x 62.4 = 467.4 lb
Air has a density of 0.075 lb/cu ft.
The air in a full cylinder weighs 0.075 x 7.35 cu ft = 0.6 lb.
The cylinder when full has a buoyancy of 467.4 lb - 50 lb = 417.4 lb
So for 4 of these you need to have 4 x 417.4 pounds or 1669.8 pounds of weight to make it neutral.
Hope this helps. You should really listen to some of the other ideas about using smaller floats...
Randy
SCUBA1951:
Now was this post really necessary?
I didn't think so.
No one in this forum claimed to be an engineer. While my degree is in Electronic Engineering with a Biomedical Engineering minor, I don't have a PE behind my name. I do have some experience in calculating buoyancy as evidenced by my previous post, which drives home the point that Divemaster B was making about something that perhaps you shouldn't do alone or even with some buddies. Underwater construction is not something to be taken lightly. Talking about task loading....
I hope that you will heed the advice that has been given in this forum by ALL that have offered their expertise. Please let us know what method you used to submerge your platform.
Randy
It seems some instructors find that teaching students actual buoyancy control requires too much time and effort, so they teach them to assume the kneeling position when performing the basic problem-solving skills. A platform to do this on helps to prevent the silt-outs a pod of such kneelers inevitably createsUncle Pug:
Capnsnott
Contributor
Dang Randy,
You sure can whip out some numbers.....
Pretty impressive, PE or not.......
I agree!
This is definately not a one person project (underwater stuff). You need a small crew to pull this off. BUT, I think you already knew that.
The rest of the rhetoric is really unjust though. KSS. Keep it simple ummmm Sir.... Yeah, that's it...
Greg
You sure can whip out some numbers.....
Pretty impressive, PE or not.......
I agree!
This is definately not a one person project (underwater stuff). You need a small crew to pull this off. BUT, I think you already knew that.
The rest of the rhetoric is really unjust though. KSS. Keep it simple ummmm Sir.... Yeah, that's it...
Greg
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