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View Full Version : LP doubles - what size?



vicp
12-11-2009, 18:03
I have a pair of faber LP108s that I really like and am considering getting doubles for cave certification (currently cavern and DM). I am trying to decide whether to double the 108s, get double LP95s or double LP85s (not really interested in HP).

I am 6'3" and 215 lbs, but find the 108s incredibly heavy and can't imagine dealing with 2 of them out of water.

I keep thinking double LP95s would be easier to deal with but I am told that the difference between 95s and 108s is not that great and that I should go with double 108s for the greater amount of gas.

What about LP85s. Who uses them? Do cavers? I know that one should try to match gas capacity with your buddies so that you don't cut their dives short.

Eventually I would like to go CCR, but in the meantime I need to do doubles.

What do you guys (and gals) use for doubles and what type of diving do you do with them?

Thanks

comet24
12-11-2009, 20:42
Depends on how much gas you need/use. LP85's balance out very nice. Might be the best setup I have dived but I like more air for most of my dives. If your in cave country though you can pump them and have a very nice setup.

For my use HP tanks are a better fit simple because I can't always count on being able to pump LP tanks.

Vlane
12-11-2009, 21:21
Depends on how much gas you need/use. LP85's balance out very nice. Might be the best setup I have dived but I like more air for most of my dives. If your in cave country though you can pump them and have a very nice setup.

For my use HP tanks are a better fit simple because I can't always count on being able to pump LP tanks.
I hate to hijack this thread but comet why do you choose to use HP tanks over LP tanks? If the LP tank has the star rating you can get the correct fill and get more gas when comparing a HP80 and LP85. Also, HP fills can be hard to get in some locations leaving you short about 10 cubic feet of gas with a standard 3000psi fill.

Not trying to start anything with this post. I've been trying to figure out the whole LP vs. HP thing for awhile now so always looking for more information.

Squidly
12-12-2009, 00:05
for a good write up on the HP vs LP thing check out:
How to Select a SCUBA Tank - Dive Gear Express (http://www.divegearexpress.com/library/tanks.shtml)

rongoodman
12-12-2009, 02:00
I like my LP85s(Worthingtons), but I'm shorter than you at 5'8". The Faber LP 85s are a little longer. If I ever need more gas, I think I'd rather add a stage than go to anything heavier. The 95s are shorter, and I've read that they make many people too head heavy. I'll be doing Cavern and Intro this May in Playa del Carmen and everything down there is Al 80s.

navyhmc
12-12-2009, 02:25
Depends on how much gas you need/use. LP85's balance out very nice. Might be the best setup I have dived but I like more air for most of my dives. If your in cave country though you can pump them and have a very nice setup.

For my use HP tanks are a better fit simple because I can't always count on being able to pump LP tanks.
I hate to hijack this thread but comet why do you choose to use HP tanks over LP tanks? If the LP tank has the star rating you can get the correct fill and get more gas when comparing a HP80 and LP85. Also, HP fills can be hard to get in some locations leaving you short about 10 cubic feet of gas with a standard 3000psi fill.

Not trying to start anything with this post. I've been trying to figure out the whole LP vs. HP thing for awhile now so always looking for more information.

A lot of cavers go for the LPs as they can overfill them and have more gas for the dive.

I will say I know a guy who doubled LP121's and then regretted it due to out of water weight and then the annual o2 clean-he said he liked to never get them cleaned and reassembled.

skdvr
12-12-2009, 06:30
I hate to hijack this thread but comet why do you choose to use HP tanks over LP tanks? If the LP tank has the star rating you can get the correct fill and get more gas when comparing a HP80 and LP85. Also, HP fills can be hard to get in some locations leaving you short about 10 cubic feet of gas with a standard 3000psi fill.

Not trying to start anything with this post. I've been trying to figure out the whole LP vs. HP thing for awhile now so always looking for more information.

If you compare the cf amount of the tanks then yes the LP tank gets slightly more air at "Actual" full pressure, BUT those tanks are not the same size. LP85 and HP100's are the same size. So at "Actual" full fill pressure HP and LP tanks of the same physical size the HP tanks will hold more gas. In certain parts of the country getting an over fill in a LP tank is easy and done all the time with a good safety record. Here in the midwest though it is not quite so easy, so I opt for the HP varity of tanks... If you go some place that cannot fill a tank to the full HP rating and can only get you to 3000psi you will actually have slightly more gas than fill a LP85 (same size as the HP100) to its full pressure of 2640psi.

I hope that makes a little sense....

Phil

vicp
12-12-2009, 08:24
Thanks for the the replies. From what everyone has said:

Assuming Faber,
double LP 108s - lots of gas, very heavy
double LP 95s - a little less gas, still heavy (head heavy?)
double LP 85s - less gas, but lighter (and better balanced)

I still prefer to use LPs as I can get them filled over 2640 psi.

Other doubles users, please chime in with preferred tank sizes, why, and the type of diving you do.

Thanks

comet24
12-12-2009, 08:41
Depends on how much gas you need/use. LP85's balance out very nice. Might be the best setup I have dived but I like more air for most of my dives. If your in cave country though you can pump them and have a very nice setup.

For my use HP tanks are a better fit simple because I can't always count on being able to pump LP tanks.
I hate to hijack this thread but comet why do you choose to use HP tanks over LP tanks? If the LP tank has the star rating you can get the correct fill and get more gas when comparing a HP80 and LP85. Also, HP fills can be hard to get in some locations leaving you short about 10 cubic feet of gas with a standard 3000psi fill.

Not trying to start anything with this post. I've been trying to figure out the whole LP vs. HP thing for awhile now so always looking for more information.

My problem is not getting HP fill it's getting someone to fill a LP tank past it's rated pressure. I can get HP fills at every place I have dived where I have taken my own tanks so far. Many of those same shop will not pump LP tanks past the rated fill pressure. The problem with LP is, for the same rated volume of gas, the tanks are bigger and heavier. If you can get your LP tanks filled passed the rated pressure they make great since. Many shops not in cave country will not fill a tank pasted the rated pressure.

Vlane
12-12-2009, 08:43
That's making more sense. I was aware of the "cave fills" that are often done but I was ignoring the tank size specs. Thanks guys and I apologize vicp for somewhat stealing your thread.

ScaredSilly
12-12-2009, 10:12
One thing to remember about ocean diving doubles and cave diving doubles. In caves you have a lot more gas, at least 1/3, always in reserve. Ocean it is based on rock bottom. I dive LP85s as most of my doubles diving is in the ocean. I would consider using them in a cave as well - I just would plan for shorter dives.

Here would be my suggestion - go try some different configurations. Otherwise, double your 108s up. If you find that they are unmanageable no harm as you can use the manifold on another set. 8" bands are not hard to find or sell.

thmoose51
12-12-2009, 11:51
At your size and being reasonably fit you shouldn't have any problem carrying the 108s out of the water. Sure, they are heavy but lots of other people dive them and you can to. I dive Worthington 95s and have dove Faber 108s and I haven't noticed a lot of difference out of the water. Unless you need a set of single 108s for other diving you ought to really enjoy the bit of extra gas the 108s give you. Whatever you decide hope you have tons of fun.

kat
12-12-2009, 14:48
Is there a maximum weight to be considered, as far as the weight being held by the BPW straps? In the water shouldn't be a problem, but walking around, could you snap a buckle? Just curious.

Vlane
12-12-2009, 15:38
Is there a maximum weight to be considered, as far as the weight being held by the BPW straps? In the water shouldn't be a problem, but walking around, could you snap a buckle? Just curious.
I can't speak from experience but I think this is highly unlikely. The majority of the weight will probably be on your shoulders by the webbing. The webbing is very durable, hence the use of it, and you would notice some fraying before it just cut. I don't think you would have to worry about the waist buckle but others may be able to clarify this more.

ianr33
12-12-2009, 15:38
I have a pair of faber LP108s that I really like and am considering getting doubles for cave certification

I am 6'3" and 215 lbs, but find the 108s incredibly heavy and can't imagine dealing with 2 of them out of water.



At most popular Florida cave sites all you have to do is stagger a few feet from a picnic table to the water.

Ever considered diving them sidemount?

ianr33
12-12-2009, 15:41
Is there a maximum weight to be considered, as far as the weight being held by the BPW straps? In the water shouldn't be a problem, but walking around, could you snap a buckle? Just curious.

The straps on a BP/W setup are probably as strong as seat belt webbing. The stainless buckles would most likely support 10 tanks. No way you're going to break anything (except maybe your back ! )

rongoodman
12-12-2009, 16:09
Even if you want a harness with a shoulder break, something like the Golem G2 with its SS buckles from the world of rescue gear would probably hold a small truck.

vicp
12-12-2009, 19:00
Thanks for all the information and replies.

It is not a matter of the harness (I have a DiveRite Transplate) holding the tanks, but rather dealing with the weight on land, going from the car or picnic table, getting into the water, and getting out, especially where there are no steps.

All the people I know that use double 108s have them set up on a truck bed or tailgate, then waddle/stagger with them into the water (central/north Florida springs). I find the single 108 challenging enough, can't imagine having 2 of them on my back. With the single 108, getting out of the water at Catfish (Manatee Springs), where there is a platform but no steps, if I didn't get a hand, I would have removed the rig, tied it off, got out, and then pulled the rig out (which I typically do when diving off a sailboat in the ocean).

If I continue with cave, I will eventually get a CCR (when finances and time for training permit), but in the meantime I need to get a doubles rig for cave that is not a nightmare to deal with on land. Maybe I should try double 108s to see if they are as bad as I think they might be. At this point I am thinking double LP85s but need to check with the people I may be diving with if this would cut their dives short.

Thanks

ianr33
12-12-2009, 19:13
Maybe I should try double 108s to see if they are as bad as I think they might be.

I'm around 6' and 200 lbs. Walking with double 104's is really not that bad. What really sucks is standing up from a sitting position. I can do it but I dont like to. (Turn over onto hands and knees,get up from there) What also sucks is carrying them around. MUCH easier with 2 people.

The ideal solution is sidemount and a moving dolly.

Vlane
12-12-2009, 22:50
Like ianr33 said, the hardest part will probably be standing up from sitting position. Another thing some divers will do is use a cart to haul the tanks near the water and put them on there.

UCFKnightDiver
12-12-2009, 22:50
As a cave diver in FL, I would get lp108's they are the universally accepted tanks (lp 95's are also popular) I am 5'11 and 200 lbs and don't have a problem carrying them, I even dive quite a few off the beaten path places where I have to walk a decent ways and dont have a problem. Per your height, I would recommend the 108's as they tend to trim out better for taller people.

As to 85's and 100's being the same with a cave fill umm no, hp 100s doubled up come out to 200 cuft lp 85's with a cave fill come out to 231 cuft

jj1987
12-13-2009, 08:07
Cave diving with Faber tanks isn't fun to me. They're not heavy enough as they approach that 1/3 reserve volume, and especially not if you had to dig into it during an emergency. I much prefer LP104's or the heavier made HP130's as they provide enough weight when near empty to comfortably blow my drysuit up to warm up a bit. If you're cave diving, it's very likely that you'll be in the water well over 2 hours on some dives, so being able to stay warm on deco is a must.

This is of course, if you're diving dry. I guess diving wet in a cave fixes this issue, although creates a much bigger one IMO.