Woefully inadequate HP80'S

[Lorenzoid]

Ive been seriously considering going to a double set for more gas and redundancy on deeper non-penetration wreck dives, however these dives require a significant boat ride to the site.Have you dived doubles from a boat? Is it practical or logisitically doable ? Do i need a seperate certification to go doubles? What training is involved and who will do the training?

There may not be a "certification" class, but there IS training you can take. I took a Doubles course offered through GUE, combined with a Drysuit course, but I am sure there are other options if you want more formal training than just someone with experience "showing you the ropes" (which is how I suspect most divers learn doubles). My course covered things like selecting the right doubles for your needs, how manifolds work, assembling a set of doubles, but the meat of it focused on achieving good buoyancy and trim and basically re-learning to do the same skills we had learned in Fundamentals only now in doubles instead of a single tank. Here: Doubles Course | Global Underwater Explorers

Some charter boats are fine with divers bringing doubles but others prohibit or discourage them because they take up space on the boat that could otherwise be occupied with single tanks and/or the boat's layout or tank holders aren't suited for stowing doubles.

 

[tursiops]

Some charter boats are fine with divers bringing doubles but others prohibit or discourage them because they take up space on the boat that could otherwise be occupied with single tanks and/or the boat's layout or tank holders aren't suited for stowing doubles.

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[Akimbo]

Exactly, one size does not fit all -- that is true for divers and dive profiles.

Hmm, I don't know, Akimbo. I own 8x LP112's and have found they can pretty much handle everything below the surface.

I'm a runt so double 45s are fine for no and light decompression dives. Unless you're talking about packing four of them, I've been on plenty of dives that required more gas than that -- volume and mixes. Maybe it's just me but I never wanted to be this guy.

Come to think of it, I've been on plenty of dives that required more gas than any ten humans could carry.

 

[MrVegas]

I think this was already implied in one of the previous replies, but maybe not stated explicitly. My only experience with HP80s was when my kid dove with them in Caribbean. He loved them -- but they only got filled to 3000psi, so he really only had about 70 cubic feet of air. It didn't matter at all for what we were doing, but obviously a little less air than a standard AL80. (Which only has 77 cubic feet, right? I'm reading way too much scubaboard if I know this.)

 

[Lobzilla]

Unfortunately, there are boat operators who think that recreational diving equals single tank like there are instructors who insist on octopus or jacket BC.

Their argument is typically "You don't need..." which really means "I don't have the understanding/skills/incentive to ..."
Just take your money elsewhere.

The GUE doubles primer @Lorenzoid mentioned is excellent and worth every penny. I was already diving doubles when I took it but learned so many little things that made diving them easier and more fun. Same experience with the GUE drysuit primer. You don't know what you don't know.

 

[flyingDiver75]

Weekly Pensacola / Destin diver, HP100's are pretty much the everyday go-to for the locals. Nice margin over 80CF tanks without a large size penalty and familiar to most shops in terms of filling them to rated pressure. Some of the DM's will dive HP120's as they have to do tie-in and un-tie drops in addition to the main dives. I can usually max out my NDL time on HP100's at depths over 70' on an appropriate Nitrox mix.

LP tanks have their place (I use double-LP85's for light deco work to 150'). Don't expect more than a + rated fill at most of the coastal dive shops unless you're friends with the owner.

If you have the chance to dive Pensacola more often, your SAC rate should settle down with a bit more local experience. The northern gulf is an eye-opener to a lot of divers on their 1st trip - deeper dives, variable visibility, surface and bottom current - but it gets a lot easier with some practice.

 

[RyanT]

@dvrdv, yes, diving doubles is easily doable from most boats. It's the only way I dive. As others have mentioned, it's possible that you might run into a few operations here and there that won't allow it. So far, I haven't had any trouble. A set of doubles will fit most boat racks just fine and it takes up the same room as everyone else's two single tanks. Aside from the advantages @Lobzilla mentioned, you also don't have to switch out your tanks between dives. I really like that, but then I'm a lazy diver!

If you go with a set of steel doubles, the first time you pick them up you'll be astounded at how heavy they are, both in and out of the water! I had a set of HP 80s doubled up and I absolutely loved them for their on-land weight. They are about 15 or so pounds lighter than a set of double 100s. Because of their short size, they do trim more "head heavy" than longer tanks. Trim-wise, I had no trouble with them, but as a set of doubles, they hung my buddy on her head. For me, they also worked great for a light tech dive or two recreational dives to 125' or less. Ultimately I stopped using them because they just didn't contain enough gas for my deeper tech dives.

Here's just a thought for your current 80s if you wanted to double them up. First, it would be a more economical way to get into doubles. The bands and manifolds cost almost as much as another tank, so you could just buy those to double up your existing tanks. Many boats won't allow you to bring two sets of doubles on a two-tank recreational trip. If you wanted to go with a set of double 80s for your gulf trips, you could probably convince the boat to allow you to bring an extra single tank and transfill some additional gas into your double 80s for dive #2. It wouldn't add a huge amount of gas, but it would be a nice little top up for your second dive.

If you decide to go the doubles route, definitely get a little practice and mentoring in an easy shallow place before venturing into the gulf with them. Diving doubles is not hard, just takes a bit of practice, especially with your manifold/valve shutdowns.

 

[Lorenzoid]

@dvrdvAs others have mentioned, it's possible that you might run into a few operations here and there that won't allow it. So far, I haven't had any trouble. A set of doubles will fit most boat racks just fine and it takes up the same room as everyone else's two single tanks.

I don't want to put words in your mouth, but if you're saying "most" dive boats worldwide accommodate divers with doubles, I'm going to disagree. US East Coast wreck diving boats are usually fine with them. In the FL Keys, some do, some don't, and some might only on certain trips. I don't know about California boats--I didn't dive much locally when I lived there. I also don't know much about Great Lakes diving, but from my minimal exposure my impression is most are fine with doubles. Elsewhere in the world, I get the impression they are common in cold-temperate water places like the UK. However, if we're talking worldwide, most recreational diving is done in tropical locations, often from smaller boats, and I can't imagine that all but a very few of those would accommodate doubles. @dvrdv indicates his location is Colorado, so I think it depends where he plans on diving, as there isn't much diving within weekend driving distance. Doubles are rarely available to rent from dive ops catering to recreational divers.

 

[RyanT]

I don't want to put words in your mouth, but if you're saying "most" dive boats worldwide accommodate divers with doubles, I'm going to disagree.

I haven't been given any static about it on the US east coast, but admittedly that's not "most." So fair enough.

 

[Akimbo]

The standard tank racks on the very popular Newton commercial dive boats are not very friendly to back-mount doubles.