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enigmatic
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Post by enigmatic »

What is the benefit to LP tanks? I thought HP was better simply due to keeping the tank smaller with the same amount of air.
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BASSMAN
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Post by BASSMAN »

I like my HP Tank (100 cf)
But, I found out by personal experience that you will not get a complete fill on a dive boat and that kind of sucks.
otherwise for the size I like them.
I'll bring my tanks full to my next boat dive or rent / borrow additional LP tanks

If I was buying new tanks today, I would considder LP 95's or HP 119's
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Post by Tangfish »

High pressure tanks are harder to get a good fill with. When the air compresses it heats up, as it cools inside the tank it condenses (and your pressure decreases accordingly). So, the higher the pressure you have to fill a tank to, the greater the 'swing' caused by the heating and cooling. Each time you fill your tank you usually have to let it cool a little before 'topping it off' to get a good fill (some people fill them in the water). HP tanks require more cycles of cooling and topping off to get a good fill.

The other way to do it is to fill your tank very slowly (better for the tank too). Once a tank is hot it is very hard to cool the air in the center of the cylinder. LP tanks on the other hand are only typically filled to around 2400 - 2600psi, so you have a lot less of this dynamic going on. Also, many situations make it impractical to get a good fill on a HP tank (restraints on time, bank pressure, compressor strength, etc.).

The final consideration is that LP tanks can be overfilled much more than HP tanks, so the resulting gain of additional air is significant. So, if you fill a LP95 to 3200psi, that is a 21% increase in air volume compared to its already + rating of 2640psi. Whereas if you overfill a HP119 to 3800 instead of 3442 that only represents a gain of about 10%. In the end, you'll have 119 cu ft. in the LP95 and 131 cu ft. in the HP119. An additional 12 cu ft is not much of a gain in terms of volume if you ask me, compared to the benefit of easier air fills and lower operating pressures. And, at any given pressure the LP tank (of the same external size) will hold more air than the HP tank. This is especially helpful when you're on dive boats, filling at a shop other than the one you're used to/who gives you really good fills or if the person filling the tank doesn't have the time to wait for it to cool and top it off so many times (usually the case).

If I had to choose between having only LP and HP tanks, I'd take the LP, though I have both for different purposes.

(Now the legal part - disclaimer: no one here at NWDC recommends filling a tank above the stated operating pressure)
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jeff98208
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Post by jeff98208 »

i dive with the hp 80 tanks. i am getting my drysuit soon, its been on layaway since the divers fair. later!

good day!
jeff :supz:
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Post by Tangfish »

I have HP80s too. I love them because they're so small and compact. There's no point to carrying around a bunch of air when my buddy is going to be done with his tank while I still have over 1k on my HP80. It saves my back, in that regard.
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enigmatic
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Post by enigmatic »

I think I'll just have to try out a few different tanks until I know what I like. Tho - LP sounds like the way to go.

Calvin - I'm setup with Dive lights! We should do a dive or two next week. ;-)
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Burntchef
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Post by Burntchef »

i sent you a pm but i went dry about 6 months ago so i now have a great oneil 7000x jtype wetsuit for sale ( real cheap ) only 20 dives on it. its a large
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jeff98208
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Post by jeff98208 »

true, but when i bought mine thats all the dive shop had. but they do work great though.
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Post by go_nudi »

Welcome to the club!

Tacoma has lots of great dives to do! Havent done any in Seattle but hope to sometime, perhaps with someone from here.

My wife and I both have a hp 100 as well as hp80 both steal. We usually dive our first dive with the 100 and do a second dive with the 80. I like the hp because it is just another option that I have for not too much more weight.

In my opinion, the dry suit is worth the $$$. I don’t have one yet but have dove with one and compared to my semi dry suit, it is nice. The one thing I hate is getting in and out of my “wet” suit. It really makes me think twice about two dive days once it is wet. Hard to get into and once your warm in the car it is so cold feeling. Just remember, $$$ buys you comfort and quality, not bragging rights when it comes to gear.
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Post by Cephlah »

Enigmatic,

It was nice to meet you at the REEF class this weekend :hello2:

If you're ever in the South end, give us a holler - we'd love to dive with you sometime. Or, we could also come North!

Take care!

:rr:
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enigmatic
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Post by enigmatic »

Thanks! it was great to meet both of you as well. I do plan to do a dive on Sunday with Holly. You're welcome to join us. I think we were thinking Three Trees?
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Post by GillyWeed »

Hey Matt,

It'll have to be Saturday. I have a class on Sunday.. I am trying to get into the doc for my back today. Not that they can do much for me as it is just a pulled muscle and I have had this before. But we can try for 3 tree point in Burien if everyone wants to do it.. If we do we should try to meet up at the Safeway in Burien and carpool down. There is only about 5 parking spots so it fills up pretty fast.

I'll keep you posted about my back.

Thanks,
Holly
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enigmatic
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Post by enigmatic »

Saturday works great for me. Just let me know how your back is doing!
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Post by Cephlah »

I'd love to go - I haven't been to 3-tree yet, but I've heard good reviews. I will have to check with nudi to make sure there are no conflicting plans.

When/where are you planning to meet?

:supz: :supz: :supz: :supz: :supz:
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Post by GillyWeed »

Hey Cephlah,

Well, I am planning on taking Matt out if my back is better.. Everything feels great right now but that's the pain meds... =)

I would probably do a 8:00am meet time at the Safeway in Burien.. We could firm up details later. The safeway is on the NW corner. If you head into burien like you are going to the airport but then pass it up.. There is a Starbucks in the parking lot, if you need to fill up... \:D/

Then we would load gear into someones vehicle.. Hopefully it would all fit. And try to take only 1 car down if we can.. The reason is that there is only about 5 spaces down there. We could take 2 cars but after that we would be pushing our luck that we would actually fit. Bassman just gave me really good directions on finding a 26' boat down there that has a 14'-15' GPO under it.. No guarantees that we would see the octo.. But we could try.. Vis is usually good at 3 tree. I have never had bad vis there. at least 20-30 feet.

Send your good vibes my way so that I can get better by Saturday please!

Hope to see you then!

Holly
"Well I, I wont go down by myself, but I'll go down with my friends!"
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enigmatic
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Post by enigmatic »

8:00am works for me! I will be there for sure (as long as I have at least one buddy. ;-)

If I got to see a GPO I'd be so amazingly happy!

Thanks Holly \:D/
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Cera
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Post by Cera »

enigmatic
I think I sat next to you on the first day.. are you the one from K-falls? I think I spoke to you on myspace... small world.
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enigmatic
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Post by enigmatic »

Indeed! I am the one from K-Falls. Yeah! very small world. Everyone has such funky avatars it's hard to put faces to the them. lol
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Cera
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Post by Cera »

OH yea, that is my Salty Dog.... not me... :smt024
I get confused, I think I just havent been around enough to figure out who everyone is either... I wish we could put more than one picture on our profile...
Cephlah
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Post by Cephlah »

Nudi and I will be there - 8 a.m. Saturday! We look forward to diving with you :)

Gillyweed - *vibe* *vibe* *vibe* - I hope your back is feeling better...having a pulled muscle in your back is NO FUN!! #-o
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enigmatic
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Post by enigmatic »

Woohoo! I'm excited about Saturday now. I looked up the dive site and saw there's a south and a north beach. Holly, do you know which one we're planning to dive?
GillyWeed
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Post by GillyWeed »

Hey Matt,

I do the north side. I haven't been on the south side of 3 tree. I think the tides are stronger there, but I am not sure. Anyway, to make sure we all have the same plan. We need to meet at the Safeway in Burien at 8:00 on Saturday. Then we can carpool or caravan down to the site.

Back is feeling a little better today. I made it through till 1:00 without needing anything for pain, which is way better than yesterday.. Keep your good vibrations coming my way, I need all the help I can get!

Cheers,

Holly
"Well I, I wont go down by myself, but I'll go down with my friends!"
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Post by Sounder »

Holly - what'd you do to your back?! I'm still healing myself!
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Tom Nic
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Post by Tom Nic »

GillyWeed wrote:
I do the north side. I haven't been on the south side of 3 tree. I think the tides are stronger there, but I am not sure.
I've never done the South, though I'd like to. There is NO parking, the only area you could put a car or three is posted... something like 5 signs. Dropping gear off would be the only option. I'd guess there haven't been many people diving it because of that.

Conditions aren't too different from North from what I've heard, though I couldn't say first hand. Most of the old reviews said that when the South is choppy the North is calm and vice versa.
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Post by Sounder »

I was told North is not bothered by tides or current, and that South can be and and is much more variable.
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