Steve-

I think that I will trust real-world experience over web specs. There was a
thread recently that pointed out the inaccuracy of PS own specs. I have 3
links to tank specs on my web site and each has different numbers.

Personally I took my rigs to a pool and used a fish scale to find out what
the difference was between HP 100's and LP 104's. I had to add a 7lb Vweight
to the HP100's make up the difference. And even with the weight they just
don't trim out as nicely as the 104's.

   Jim
 -------------------------------------------------------------------
 Learn About Trimix at http://www.cisatlantic.com/trimix/

> From: Steve <sfkenney@ea*.ne*>
> Date: Sun, 05 Aug 2001 07:27:41 -0700
> To: Jim Cobb <cobber@ci*.co*>, Daniel Smith <Daniel_Smith@co*.co*>,
> <techdiver@aquanaut.com>, <dlhedrick@pb*.co*>
> Subject: Re: tanks
> 
> Jim, I went to the source of tanks for my info. The Pressed Steel Co.
> 
> http://www.pstscuba.com/aapro.htm
> 
> I was wrong the HP100 is more negative than the LP104 when empty. -1.4
> compared to -.7 pounds, the HP120 is -.4
> 
> As far as rust goes I believe that depends on who fills the tank and whether
> their are pumping dry air or not. Mine hasn't had any rust in the six years
> and it passed hydro.
> 
> Steve
> ps: I'm not a tech diver but I'm studying tank spec's making plans.
> 
> 
> 
> 
> on 8/5/01 6:54 AM, Jim Cobb at cobber@ci*.co* wrote:
> 
>> I guess it depends on whose specs you read this from. I guess the question I
>> have to ask you is do you have 104's and HP120s and can you move back and
>> forth between the two with no buoyancy changes? The folks I know who do say
>> there is a considerable change.
>> 
>> You also have to ask yourself why do tanks rated at 120cuft at a high
>> pressure weight less than 104cuft tanks at low pressure. Obviously the
>> answer is that the HP120's have less robust structure than LPs. And for some
>> reason the HP have a high propensity to rust internally, I have seen this
>> myself.
>> 
>> So with the 104's you have a more negative tank and you can put 120cuft in
>> them easily. They are shorter and the center of buoyancy is higher up your
>> back which offsets the  weight of the light canister and other items you
>> carry on your belt. You can purchase off the shelf manifolds for them which
>> cost less and are easier to find.
>> 
>> The whole point is that if you need a set of doubles, go for the 104's,
>> don't buy HP120's new or used. There is absolutely no advantage to them in
>> any respect.
>> 
>> Jim
>> -------------------------------------------------------------------
>> Learn About Trimix at http://www.cisatlantic.com/trimix/
>> 
>>> From: Steve <sfkenney@ea*.ne*>
>>> Date: Sat, 04 Aug 2001 20:40:57 -0700
>>> To: Jim Cobb <cobber@ci*.co*>, Daniel Smith
>>> <Daniel_Smith@co*.co*>,
>>> <techdiver@aquanaut.com>, <dlhedrick@pb*.co*>
>>> Subject: Re: tanks
>>> 
>>> I didn't miss that part. If you see I pointed out that the tanks have the
>>> same buoyancy characteristics underwater which is neutral when empty. So
>>> logically if you didn't need a weight belt for the LP you wouldn't need one
>>> for the HP. Or what am I missing?
>>> 
>>> Steve
>>> 
>>> 
>>> 
>>> on 8/4/01 7:50 PM, Jim Cobb at cobber@ci*.co* wrote:
>>> 
>>>> You missed the part about "don't need a weight belt". I don't like weight
>>>> belts, they are just one more thing to screw up and they mess up the air
>>>> distribution in your drysuit. You either wear the weight you need on your
>>>> back or you add it on with a weight belt, so there are no savings when
>>>> climbing up a ladder with HP's.
>>>> 
>>>> Jim
>>>> -------------------------------------------------------------------
>>>> Learn About Trimix at http://www.cisatlantic.com/trimix/
>>>> 
>>>>> From: Steve <sfkenney@ea*.ne*>
>>>>> Date: Sat, 04 Aug 2001 11:04:39 -0700
>>>>> To: Jim Cobb <cobber@ci*.co*>, Daniel Smith
>>>>> <Daniel_Smith@co*.co*>,
>>>>> <techdiver@aquanaut.com>, <dlhedrick@pb*.co*>
>>>>> Subject: Re: tanks
>>>>> 
>>>>> on 8/3/01 11:12 AM, Jim Cobb at cobber@ci*.co* wrote:
>>>>> 
>>>>>> There are some who swear by HP120's but once they try a set of LP104's
>>>>>> they
>>>>>> don't go back. Why are the 104's so perfect? Buoyancy characteristics.
>>>>>> You
>>>>>> can remain neutral throughout your dive and avoid a weightbelt.
>>>>> 
>>>>> 
>>>>> Buoyancy characteristics of tanks is definitely something to study before
>>>>> buying. My research reveals that the Pressed Steel tank whether low or
>>>>> high
>>>>> pressure all have near neutral buoyancy when empty. I thought there were
>>>>> other reasons why you would choose the low pressure over the high. Like
>>>>> getting full or overfilled tanks, many can't pump to 3500 psi. Also a low
>>>>> pressure does exert less stress on o-rings. One drawback is the overall
>>>>> weight of the low pressure tank. Empty weight is 46 lbs for LB 104
>>>>> compared
>>>>> to 31 lbs for a HP 100. An extra 30 pounds may not mean much once your in
>>>>> the water but climbing some boat ladders is where you'll feel the
>>>>> difference. It's tough hoisting a set of small twin HP's over your head to
>>>>> donn let along adding another 30 pounds. <g>
>>>>> 
>>>>> Steve
>>>>> 
>>>>> 
>>>> 
>>>> 
>>> 
>>> --
>>> Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'.
>>> Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
>>> 
>> 
>> 
> 
> 


--
Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'.
Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.

Navigate by Author: [Previous] [Next] [Author Search Index]
Navigate by Subject: [Previous] [Next] [Subject Search Index]

[Send Reply] [Send Message with New Topic]

[Search Selection] [Mailing List Home] [Home]