Yet another LP85 vs HP100 doubles question

[Kevin Floyd]

FWIW I’m 6’3 275 and have a set of LP98’s (don’t know the make…I need to post pics to see if anyone knows…I got them second third hand from a dive Buddy moving to CCR when I was getting into DM OC) and a set of Worthington HP 100s. The Worthingtons are much smaller and lighter. I prefer the LP98’s when I can get them cave filled but in TX that’s a tall order. I only know of one guy that will fill them to 3100 because he “forgets to change the settings”

 

[formernuke]

My preferred set up is the twin LP85,s for my body size (5'10" 165 lbs) and exposure suits (wet and dry suits) they
trim out very nicely and ride closer to my back than 100's. As you point out they can be overfilled
if the fill operator is comfortable doing that to get the same or more gas than the 100's.
It really depends on the depth, your SAC rate, and type of dive being undertaken as to which set up would be better for you. I also dive twin LP 50,s as opposed to a single HP100 for many of the same reasons stated above.
I prefer the galvanized finish over the painted as the paint always gets nicked up.
I have been diving twin sets since 1995 in the Northeast and south Florida. If you can try to rent or
borrow to try them out to see what works for you.

I used to dive double 120's to much weight for me nowadays.

I love my double 50's for shore diving and just set up a set of 100's for boat and starting tec training.

This makes me wonder if I should make sure to.get my friends LP85's when she moves. I have my own compressor so cave fill is no issue.

 

[tbone1004]

LP's any day for me over HP. The HP s are going to be harder to fill if your in a pinch on time and not allowing them time to cool down and top off.

uhhh what? that holds if you compare say a LP80 and a HP80, but we are talking about two tanks that are the essentially the same volume which means they hold the same amount of gas when filled to the same pressure.

 

[boriss]

if given the choice I will almost always go for HP tanks vs LP tanks for backmount doubles. Sidemount has some weird buoyancy and trim issues where lighter is usually better, but not generally so with doubles.
Tank length is not something brought up yet and while it is only about 3/4 of an inch with the Fabers, it is there and with the HP100's being a bit shorter that's better for most.

@Dominick Marino the OP stated correctly that the HP100's and LP85's hold functionally the same amount of gas when filled to the same pressure *the 85's hold about 1% more gas, but that's not significant*.

@Ian Fatzinger since you're in Hawaii I would stick with AL80's due to the climate more than anything. Trying to keep steel tanks dry and free of rust out there is going to be a losing battle.

So, forget about the additional -6lbs and bite the bullet? I'd prefer longer/skinnier profile of the LP85's, but TBH, I've tried so many cylinders already and am able to adapt to them all (even some shorty HP80's!). I'm just over 6ft tall. As long as you attach them to the plate properly they all just balance on the plate well.

LP's any day for me over HP. The HP s are going to be harder to fill if your in a pinch on time and not allowing them time to cool down and top off.

You get equivalent volume of air in both at the same pressure, but you don't have to "hope" for overfills with LP's. Heck, I was diving HP's today and got them overfilled to 3.8k. Outside of caves, I don't think I can ask someone to do that with LP's locally. Anyway, I see this as a common misunderstanding between the two cylinders, which is why I asked in the Technical Diving section. Hoping people here know the difference. They're both ~13L tanks, the only difference is buoyancy consideration and I'm trying to figure out if extra gas is better than less weight.

I'm pretty sure I know the answer, but having someone like @tbone1004 give his blessing and make sure I'm not "missing" something is all I really need.

When I faced this decision, the price difference was not marginal (HP was nearly 40% more expensive). Outside of that, I chose LP85s because narrower, lighter on land, and perfectly weight me in the temperate conditions I typically dive (drysuit, medium layers). (As an aside, I will also likely explore side mount at some point, and I have to think being closer to neutral is better for that application.)

Interesting, the difference is about 10% or $80 right now. With drysuit HP100's are a no-brainer, but for side-mount LP85's are a no-brainer. Your decision is easier than mine: both

 

[_Ralph]

How much gas do you require for your intended dives?

As pointed out, they hold roughly the same volume of gas…

If you need >170cuft, no brainer, get the 100’s

If you can routinely get ‘cave fills’ on tanks wherever you would ever fill up (including travelling out of cave country), then the choice isn’t as easy…

Personally.. backmount, drysuit, I’d go with the 100’s. Less worry about having the fill pressure required for a dive when going to a new area for a fill.


_R

 

[Tracy]

They dive the same, When buying new, if price is similar, always go for HP tanks.

 

[tbone1004]

@boriss it's much more of an opinion, but that's personally what I would do. The LP85's are great tanks for sidemount because of their buoyancy characteristics and they're great doubles as well, but when Faber came out with the new FX100's that are longer than the PST and WAY longer than the Worthingtons, they're a much more balanced tank.

 

[boriss]

They dive the same, When buying new, if price is similar, always go for HP tanks.

@boriss it's much more of an opinion, but that's personally what I would do. The LP85's are great tanks for sidemount because of their buoyancy characteristics and they're great doubles as well, but when Faber came out with the new FX100's that are longer than the PST and WAY longer than the Worthingtons, they're a much more balanced tank.

Thank you both, that's all I needed to hear. Will be picking up my HP100 doubles tomorrow (hopefully! )

By the way.... @tbone1004 you're such a huge asset to this forum, I just wanted to let you know. I haven't read a thread yet where you didn't offer some pretty amazing information. If it weren't for your posts and articles on DGX site by @mderrick I'd still be just as confused as everyone else seems to be about LP85's vs HP100's. If you're ever in SE Florida, dinner/drinks on me. Thanks again!

 

[divezonescuba]

The OP specified the LP85s as Fabers. After that some of the threads genericized the tanks to just LP85s. It may be worth noting for those that do not know, that there is a significant difference in the bouyancy characteristics between Faber LP85s and the Worthington LP85s. If this is not taken into account the expected results may not be achieved.

I am 5’7” and weigh about 175. My preferred backmount tanks for ground transportation diving are faber LP85s. But, I would not dive with worthington lp85s because of the differences in the bouyancy, if I could help it.

However, most places internationally do not have lp85 twinsets of either manufacturer. AL80 twinsets on the other hand are readily available in places like Bonaire, the caymans, and Egypt. The amount and placement of any necessary weight differs significantly between the two. So, we always make sure that anyone going on an international trip be aware of that if they dive steels locally.

If you are assembling your own set this may be helpful

 

[OrcasC205]

The Worthington LP85's trim and buoyancy is much closer to a Faber HP100 than to a Worthington HP100 or a Faber LP85. I have a set double Faber HP100s and a set of double Worthington LP85s and I have trouble telling them apart from a trim and buoyancy perspective.