Thinking Diver » Gear

Backplate, Harness, Wing for recreational divers

Twain — Tue, 24 Nov 2009 13:09:36 +0000

You’re thinking about buying a BC. You’ve got 100 dives under your belt, or perhaps you’ve just done your PADI Open Water. You believe your BC will be critical building-block piece of your scuba rig and buying your own instead of renting will help you progress as a diver. Here’s a tip: don’t buy a (jacket) BC.

This is another tip in the category of “what I wish I’d known” back when I bought my original scuba equipment. Your average dive magazine and dive shop are filled with ads for fancy jacket BCs that have all sorts of bells and whistles – sometimes literally! Yet every technical diver I know including myself uses a different system called a Backplate & Wing (or BP&W) that is both stronger and cheaper and easier to use. Why? Keep reading.

Jacket BCs

Jacket-style BCs are what you see most in recreational scuba diving magazines. A jacket BC is a nylon fabric vest attached to a plastic backpiece. The buoyancy function of the jacket comes from inflation cells usually located under the arms and up the back. You can attach a single tank to the back via an integrated strap. Jacket-style BCs are common items in your local scuba store and usually command an entire rack of hangers to themselves. Jacket-style BCs are what you would rent at a resort or in a PADI diving class.

What Jacket BCs do well: quick easy sizing

Jacket BCs come in sizes like S, M, and L. These three sizes will cover 99.9% of the human population and are recognizable by anyone that’s ever worn a t-shirt. Cinch the velcro cummerbun as tight as you can and presto! You’ve got a BC that pretty much fits with less than 30 seconds of hassle. This makes jacket BCs perfect for use in rental shops and resorts where stocking a large variety of sizes would be too expensive.

However, if you are buying your own BC you don’t care about needing to cover a large variety of sizes. All you care about is your size. You are not trying to open a rental shop. The ideal BC is one that fits you perfectly.

Why is fit so important? Jacket BCs are like an oversize set of pants you hold up with a belt: sure they cover your ass but you’re swimming (in this case literally) around inside of them. And in this case, you use them to attach all sorts of heavy equipment to your body. When under water, you want your tank and weights to be snug to your body so that they are not sliding around every time you turn or look around. A jacket BC cannot do this well.

What Jacket BCs do well: heads-up flotation on the surface

A jacket BC puts the inflation cells under your arms. This can be useful because you can super-inflate the cells on the surface and they will hold you in an easy vertical position with your face way out of the water. This is perfect for beginner divers where being under water is the “scary” zone and the surface is the “safe” zone. If they are not comfortable with a dive or if they need to discuss something with their instructor they can hang out on the surface in an inflated armchair.

Sounds good right? Forget it. The more diving you do, the more comfortable you become with being under water. The surface zone has breaking waves, boats with ladders that will whack you on the head, low-PO2 ambient air — all sorts of drawbacks! Who wants to hang out on the surface?

Plus, inflation cells under your arms get in your way when inflated. As your diving skill increases you will likely be taking more things underwater with you: cameras, lobster bags, extra tanks, scooters, or even an ironing board. Your chest and arm areas become your “work zone” for attaching stuff. You need to keep this area clean and not puffed-up with a vest.

Furthermore, jacket inflation widens your profile in the water. You want to be as streamlined as possible underwater so that you expend less effort (and consume less gas) when swimming and are less susceptible to the pull of current. The under-arm inflation cells on a jacket BC will scoop water when swimming and cause drag.

So if jacket BCs are so bad, what’s better?

Backplate & Wing

A backplate & wing (or BP&W) is a flat rectangular metal plate that you attach to your back using a nylon webbing strap. Buoyancy comes from a doughnut-shaped cell (the “wing”) that goes on your back between the plate and your tank. The whole thing resembles a parachute harness. If your local scuba store doesn’t carry plates or wings you can easily order them online.

What BP&W does well: fit

The harness on a backplate is designed to be tight. You should be able to stick a couple of fingers between your suit and the harness straps, but that’s it.

Under water this means you and your scuba rig melded together as one piece. If you tilt downwards to look under a coral head, your rig stays tightly in place and doesn’t flop suddenly forwards and whack you on your head (done that!). If you tilt to the side, the rig stays fixed in the middle of your back instead of sliding off like a deckchair on the Titanic. A nice tight rig means you stop thinking about even having a rig attached so you can start focusing on the rest of your diving.

What BP&W does well: simplicity

A metal plate to hold things, a nylon strap to attach it to your back, and one inflation cell — what could be simpler? The plate and strap are near-indestructible but if you need to fix something you can do it with parts from a hardware store. The entire setup is open and obvious.

Under water a simple setup is crucial because you need to perform actions quickly and get them right the first time. You can’t see your own body to guide your hands because the mask interferes with your peripheral vision. If you’re wearing cold-water gloves or a wet/drysuit you also don’t have your sense of feel and the dexterity required to grope your way though a complex attachment or piece of equipment. A plate & harness excels here because it’s as simple as possible, and no simpler.

What BP&W does well: strength

Extreme strength may not seem necessary for the beginner or intermediate diver. You’re not attaching two hundred pounds of steel doubles tanks and lead weight. However, it’s good to know that your standard harness and plate can easily do that if you need it. The plate is steel or aluminum. The harness is 2-inch wide nylon, sometimes stiffened with resin. Buckles and attachment points are stainless steel.

You may not need all this strength, but it’s there if you need it. Your standard jacket BC with velcro attachments and thin nylon fabric will tear or drop that underwater camera when you least want it…like on the deck of the boat when you’re getting out in heavy seas.

Technical divers will also site an additional list of reasons why a BP&W is better than a jacket BC, for example that it provides standardization of equipment so that buddies on a diving team are guaranteed to know their partner’s rig as well as they know their own.

What About Cost?

One of the things I like about diving is that good technical equipment often costs less than the highly-advertised gear you see in scuba magazines. Let’s see if this is true for backplates and jacket BCs too.

Jacket BC Costs

These prices are from LeisurePro. I tried to pick the model from each manufacturer that best represented a high-end recreational BC, the kind of thing you would want to buy for yourself (versus rent at a resort).

Brand	Model	Cost
Cressi-sub	Aquaride	$400
Mares	Dragon	$550
Tusa	Platina Evolution	$280
Aeris	Atmos LX	$550
Mares	Probe LX	$570
Average		$470

BP&W Costs

You can buy a backplate, harness, and wing separately if you wish. You can also often find them sold together as a package deal. If you buy separately, you should get a tank strap to attach the tank to your plate.

	Backplate	Harness	Wing	Tank Strap
DiveRite	$87	$35	$350	$32
OxyCheq		$38	$272
Salvo	$140		$350	$28
Average	$113	$37	$291	$30

Total price of the average piece prices: $471!

However, you can also find some package deals, like these:

ScubaToys BP&W package: $319
Golem Gear BP&W package: $390

So, not only is a BP&W better fitting / stronger / easier to use than a jacket BC, it’s also equal price (or cheaper!). What are you waiting for?

Convinced yet?

You still have a few choices to make if you decide on a BP&W instead of a jacket BC. Some recommendations:

Harness: “Hogarthian” or “Deluxe”? A Hogarthian (named for the diving minimalist William Hogarth Main) harness is the basic, simple harness. “Deluxe” harnesses take a Hogarthian one and then add plastic buckles and extra straps. In this case, simplicity is better. Go with a Hogarthian. If you really feel the need to pimp out your rig, you can get nice soft Polypro webbing for your harness (I like it myself).
Plate: aluminum or steel? This is a weighting question. A steel plate is approximately five pounds more negatively buoyant than an aluminum plate. If you need a lot of weight to dive (e.g. for cold water and a drysuit) a steel plate will relocate the weight off your belt and into the backplate which will be much more comfortable. If you travel by plane to dive, get an aluminum plate.
Wing: how many pounds of lift? For typical single-tank open-circuit diving a 35lb or 40lb wing is quite sufficient. You don’t want a ginormous 60lb wing because the excessive size will cause drag.

Note: I’m not a scuba instructor and I’ve never played one on TV. If you’re an instructor or diver with the experience to recommend something to the next generation of up-and-comers, what would you suggest they get when buying their own set of equipment?

Titan Dive Gear Hydrolights X-Series 25W LED Dive Light review

frenchguy — Mon, 26 Oct 2009 13:50:12 +0000

A few years ago, I purchased a 10W HID canister dive light from a well know manufacturer. After a few dives on our northeast wrecks, I realized this was the wrong choice for me.

The 10W HID I had bought was not very powerful of course but most importantly I didn’t think it would endure the rigors of diving around Boston but more importantly the way I treat equipment. There was too much potential harm that could come to such a light. Having to open the canister to remove and charge the battery, potentially damaging the (user replaceable) o-rings and compromising the water tightness of the canister, thus risking a flood, wasn’t desirable.

HID bulbs are notoriously fragile and I had heard horror stories. Moreover, used to quality chargers in electronics such as laptops, I was appalled by the build and functionality of dive light chargers, some didn’t even have charge indicators. They looked like a $10 Radio Shack power brick hacked into a battery charger with a pair of scissors, some masking tape and cheap components.

Determined as I was to find a tougher, brighter and better light, I set my eyes on the Titan Dive Gear HydroLights X-Series. Titan Dive Gear’s other line of dive lights, the SCULA, has a battery built into the light head but can also tether to a battery canister.

I bought the 25W X-series which uses 7 LEDs for its max illumination and 3 to reach a dimmer 10W like illumination. The 25W X-series retails for $1065.00 with the smaller of the batteries (lasts plenty though). LED lights are very tough as there are no bulbs to break and I feel fine throwing my lights in my dive bag with all my other gear. The X-series is built tough from the head to the cable (and connector) to the battery. In fact, each light is tested to 600ft for three hours in a water pressure pot before they leave the factory.

Let’s talk a bit about the connector and LiCo (Lithium Cobalt) battery canister. To charge the battery, you simply connect the charger directly to the canister. To use the light, you’ll connect the light cable to the battery on one side and to the light head. on the other. The battery canister doesn’t open and you don’t need it to. As you can see, it’s very foolproof. Also, when the batteries are fully charged, the LED on the charger will turn green. This might seem obvious but not all dive light chargers do that. Also, I find the Titan batteries to be exceptionally light and small for their capacity. In fact they’re so small that I prefer to stick the canister somewhere on my rebreather than on my harness belt. The magnetic switch on the light head (instead of somewhere on the cannister) makes that pretty easy.

I have been using my light for about a year now and it’s still going strong. I keep a couple of batteries around, one that lasts nearly 5 hours at 25W and 12 hours at 10 W. The other one smaller (they’re both small compared even to a 10W HID canister, not to mention the big 21W or 35W canisters) will last 8 hours at 10W and a little over 3 hours at 25W.

Still, no piece of gear is perfect so let me nitpick a bit:

the 25W X-series head is a little on the bulky side, it doesn’t always balance well on your hand.
the Hydro Light glove, a soft goodman handle does a decent job but it’s not amazing. Some will prefer a stiff goodman handle
Spare parts for the X-series are available but a replacement 120W is $525, a spare cable is $120. On top of the $1200 25W X-series, grabbing a spare battery and cable brings the total cost to a whopping $1845. Because you have to pay for the canister on top of the battery element, spare batteries are more expensive than on a classic canister light.
8

ACR Electronics Firefly Plus – Dive Strobe Light Review

frenchguy — Wed, 30 Sep 2009 14:55:14 +0000

I often dive in cold dark waters. Once or twice, I got disoriented on a wreck and had some difficulty finding the up line. Also, after reading a few reports of survival at sea, I figured out having a strobe at the surface would also be a good thing.

I tried a few strobes and settled on the ACR Electronics Firefly Plus. While not a dive specific strobe, people seem to agree that this is one of the top choices for diving.

The Firefly Plus (find the Spec Sheet here) is well built and doesn’t seem to be plagued with the flooding issues that many more expensive strobes have. It doesn’t mean that you shouldn’t maintain the strobe’s oring and be generally careful.

The Firefly Plus is small and light (5.3 x 1.5 in and 5 oz), sports a strobe (bright!), a flashlight (useless underwater), is slightly positively buoyant and withstand depths of up to 330ft (100m). I didn’t take it to such depth but used it at 100+ feet in poor visibility waters and it worked well, the strobe light showing me the upline from quite a distance. The Firefly 3 doesn’t come with an adequate way to tie the strobe to the upline or a wreck. A bit of bungee cord solves that problem.

The dive light operates on 2 AA alkaline or 2 AA lithium batteries and the strobe is supposed to work for 10 hours. I haven’t tested that, I have to say. The flashlight is pretty much useless unless you want to signal at sea I guess.

In any case, the Firefly 3 is an inexpensive and good strobe light. At $32 or so, it costs less than half of the alternatives and holds up well against the competition. I always have one on me whether it is to mark the upline or as a safety should I get lost at sea.

ThinkingDiver T-shirts

frenchguy — Fri, 27 Feb 2009 18:21:02 +0000

We haven’t been diving much recently and as such it doesn’t feel right to write about scuba as a couch diver. While we’re gearing up for some adventures in the next few months, we’re also making plans to attend both the Boston Sea Rovers and Beneath the Sea shows. To do that in style and for those who’d like one, we’ve made available a few ThinkingDiver shirts, using the new logo designed by Alphabet Arm. Here they are:

The shirts are made to order by Spreadshirt, following my design. Which explains the price that, yes, is a little high. I did receive a few I had ordered, they look really nice, the logo came out really well.

New paper on the thermal characteristics of Argon

frenchguy — Wed, 18 Feb 2009 04:23:27 +0000

This new paper seems to do a better job at establishing the usefulness of Argon in dry suit inflation for cold water diving than a prior document did.

It’s worth reading completely but here is the conclusion: “This investigation has demonstrated that significant improvements in drysuit thermal protection can be achieved when using argon instead of air as a drysuit inflation gas. It should be noted however that these improvements can only be achieved by carefully and repeatedly purging (a minimum of 6 purge cycles) with pure argon prior to water entry”

Why a third computer ?

frenchguy — Thu, 15 Jan 2009 14:05:48 +0000

People ask me why I use three computers on my rebreather. It’s a good question and frankly the decision is probably based on personal preference, careful planning, irrational fears and wrong assumptions.

The default set up for my Dive Rite O2ptima rebreather is two Hammerhead handsets. The primary is used to drive the Solenoid (which injects oxygen into the loop) and provides decompression information (Buhlman GF) as well as a read on the O2 Cells 1,2 and 3. The secondary is used to drive the Diva HUD (Head Up display with vibrating capabilities) displaying information from the same cells there as well as on its display. A lot of O2ptima divers dive their rebreather this way with one handset on each arm and the HUD.

Some choose to get the optional deco capability on the secondary handset, a $500 pin code from Hammerhead and a reasonably good choice which gets you a backup decompression computer should the primary fail (and you find yourself manually running your rebreather, using SCR mode or bailing out on Open Circuit).

The O2ptima has a neat feature which allows you to install a fourth sensor that can be read from a third party computer connected via a fisher cable. That’s what I was doing with some degree of success and failure with my VR3. This gives you a second deco computer, possibly a different deco algorithm and a fourth cell to get O2 readings from. Unfortunately a fourth cell can fail or behave erratically and as such I didn’t trust the VR3 as much as I would have wanted to. It also always seemed to be reading .10 higher than cell 1,2,3 which bothered me. One could also use a Liquivision X1, Shearwater Pursuit or Delta-P VRX with this scheme, reading from one sensor.

Having switched to the Liquivision X1 from the VR3 and following closely the announcements for the PPO2 interface, the X-Link, I have been working on a solution to connect three cells to a Fisher cable. Kevin from HammerHead set my head up with a split harness and 5 wires Fisher cable so I could continue monitoring Sensors 1,2,3 with the HammerHead handsets in addition to Sensors 1,2,4 with my Liquivision X1/X-link. Of course the same could be done with a Shearwater Pursuit or Delta-p VRX.

So what do I like about this setup ?

O2 readings from 4 cells instead of 3 with voting logic on cells 1,2 and 4 for the external PPO2 reading
Different software and hardware. If the HH primary handset was to freeze up due to an odd software issue (as opposed to electrical) it’s entirely possible the same thing could happen on my secondary. With the Liquivision X1, I am on a different hardware and software platform, one altogether different bugs maybe but _different_ is the key. Redundancy through additional and different hardware/software.
VPM algorithm vs Bulhman GF. Always good to have two different profiles from two different algorithm
Different voting algorithm on a different group of cells
Possibility to fall back to 2 cell, one or constant PPO2 if I need to
Very easy to configure the bailout gases (not that the HH or VR3 were that hard just not very quick to configure)
Same deco computer, parameters, profile and as such deco plan as my usual dive buddy
the X1 is very bright which is great for dark water diving (hello Boston). Also, I can see my buddy’s PPO2 from 10 feet away
Same software for planning dives (V-planner) and diving those plans. Plan your dive, dive your plan

And while Fisher cables can be problematic, when well maintained they are reliable. Now, I still have and use my two HammerHead handsets. With the secondary tucked away in a belt pocket, the HUD and primary remain my main dive instruments.

The Liquivision is a very good backup and could be the primary if I had a different setup (MCCR or OC, for example) and could be substituted by a Shearwater Pursuit or a Delta-p VRX. In addition to tables, of course and a deco plan written on white electrical tape.

Fins: what I wish I’d known

Twain — Tue, 13 Jan 2009 18:36:17 +0000

I wince when I think of the money I’ve wasted on bad gear as I was learning to dive. Maybe it’s my propensity for shiny new toys, but I’d rather blame it on a communications gap between the “technical” and recreational dive worlds.

Every year dive gear manufacturers come out with new features for their regulators, wetsuits, and BCs. There’s a good business reason for this: manufacturers need to differentiate their product and get consumers to buy more each year. It’s hard to build a business around a commoditized simple item. I suspect golf is like this too.

The irony is that diving is one of the few gear-intensive sports where the best stuff is the simplest and often cheapest. By the time you get to technical diving you know this, but meanwhile you’ve wasted a fortune on recreational junk which you could have avoided had there been a nearby technical diver to ask.

So here is the first of my “I wish I’d known that” gear posts.

Fins

Fins are important. They are how you control your movement under water: forwards, backwards, and turning. (Yes, turning – your hands are for handling gear not swimming.)

I recommend two things to consider when choosing fins. One is obvious, the other maybe not.

Fins Shape – Split or Paddle?

Oh, I wish someone had pointed this out to me before I’d started buying gear.

A very popular design these days is the “split” fin. (I used a set of these for several years.)

What split fins do well: high-rpm flutter kicking. When you flutter kick, each “leaf” twists creating a propeller-like effect. This makes it quite good for fast flutter kicks and straight-line speed tests. Sounds great, right?

However, here’s the kicker (sorry, couldn’t resist!) — you are not high-rpm flutter kicking when scuba diving!

First of all, you shouldn’t be swimming hard to begin with — if you are working hard, something is wrong. Working hard will chew through your gas if you’re on open circuit or put you at risk of carbon dioxide buildup if you’re on a rebreather. If I could drift or get pulled (scooter!) the entire dive that would be just perfect.

Second, the kick of choice for advanced diving is not a flutter kick. Flutter kicks push water downwards to cause billows of visibility-killing silt or disturb reef life. If you flutter kicked through a wreck you would likely piss off or endanger nearby divers with clouds of silt.

What split fins lack: the stiffness and body you need for frog-kicking, turning and backing up.

Frog kicking – this is the kick used by technical divers because it pushes water behind you where it won’t stir up silt. The short, sideways motion of a frog kick does nothing if you have a fin designed to be moved vertically.

Turning – you pivot your body underwater by moving your fins in small vertical circles. Doing this with a split fin makes the “leaves” of the fin flutter and inhibit the sideways foot motion, accomplishing almost nothing.

Backing up is even worse…you are trying to pull water towards yourself but your “scoop” is functioning like a fork instead of a spoon. OK, maybe a spork. You might as well be barefoot.

Dive computers Reviews – Part Two – the Liquivision X1

frenchguy — Fri, 05 Dec 2008 13:01:02 +0000

Disclaimers

A decompression computer is not a substitute for planning your dive and carrying decompression tables. Plan your dive, dive your plan and carry backups tables.
I paid full price for my Liquivision X1 (bought it used off a bloke in Canada) but I will be getting a Liquivision X-link for 50% of the list price because I am working on a 2 pager about using the X-link with a Dive Rite O2ptima for Liquivision.
My experience is with the X1 is only with the V-Planner Live software installed. This post relates to this particular configuration unless otherwise noted.

Experience

When I bought my rebreather, I already had a Delta-P VR3. In addition to that deco computer (which I bought the Trimix and Rebreather/PPO2 software pins for) my O2ptima comes with a Hammerhead primary handset that’s deco-enabled (Buhlman GF). Having just spent so much money on diving equipment I wasn’t looking to buy a new deco computer.

Six months later, my dive buddy Sam bought a Megalodon Copis rebreather. Since the basic Copis doesn’t come with a deco capable computer (really just a PPO2 display) he chose to buy the new Liquivision X1. At the time, not much was known about the X1 but he had seen me struggle with the VR3 and thought the user interface was awful. The idea of being able to chose which software to put on the X1 was attractive as was its user interface both in terms of tapping and screen display.

I actually didn’t think the X1 was a great choice for him at the time as the X-link wasn’t available (it still isn’t at the time of this writing but should ship mid-december 2008) so the X1 could only give him deco information based on a pre-set PPO2 as opposed to reading it real time the way my connected VR3 did. I thought this was especially true of a manual CCR like the Copis he bought. In any case, he loved his X1 and after diving a few times with him as my VR3 failed again and again I went ahead and bought a used (but never wet) X1.

Today I am really glad I made this choice. I have made 23 dives and spent 30 hours in the water (saltwater dives from 20ft to 173ft) with the X1, had no issues with it and I must say I am loving it.

V-Planner Live

Sam and I have been planning our dives using the V-Planner software for a little while now. People have varied degrees of success planning a dive with V-Planner in a way that’s consistent to a VR3 (even a VPM enabled one). Also the VR3 is very very conservative and when I was diving it in conjunction with the X1 and the Hammerhead, the VR3 would always keep me in the water much much longer than any of the other two. As mentioned previously, the X1 comes with no software (but a simple Bottom Timer), you chose what you want to put on it. Two different programs exist for it. I bought V-Planner Live which gives me the exact same profile than V-Planner the desktop version. An alternative to V-planner exists in GAP X1, based on Buhlmann GF (currently priced at ?80 – will eventually be ?120) but I have no experience with it. V-Planner Live on the X1 is extremely easy to use. The diver interacts with the computer by gently tapping it. While it can be odd at first, it becomes natural very quickly. The display is astonishingly bright and the V-Planner UI is very clear and shows on the small X1 screen all the information you need on a dive.

Pros/Cons

Pros

Extremely clear and bright display
Choice of software and deco models
Small unit, easy to throw in your laptop bag
USB Connection and dive log transfer (PC only, I use VMWare Fusion on a Mac)
Support for the X1 and V-Planner live available on Liquivision Forums
On V-Planner Live, bailout gas and dive planning are very easy to configure. Bailout to OC is very easy to do.
Great UI with V-Planner combined with the great physical interface (tapping & OLED screen) of the X1
V-Planner Live is updated often as is the X1 firmware and easy to upload on the X1
Integrated electronic compass (though I had difficulties with it)
PPO2 monitor available soon (Dec 2008) which monitors up to 3 O2 sensors (and CO2 when available)
Battery will hold charge for a week of diving in most cases

X1 Simulation Dive

Cons

Wristband looks inadequate. I replaced mine with a depth compensating (found on the VR3 or Hammerhead handsets). DSS also makes a bungee mount for the X1.
Battery is potted in and as such not user replaceable. A replacement program exists but many are concerned by the long term impact.
In a humid environment the wet switches prevent the X1 from shutting down the display which can affect battery performance.
Pricey at US$1750 but similar in price to Trimix-enabled, constant PPO2 VR3. ShearWater Pursuit is $150 cheaper.
No dive planning feature in V-Planer Live

Liquivision X1 vs Delta-P VR3

	Delta-P VR3	Liquivision X1	Comment
Form Factor	Large, irregular shape, heavy	Small, compact	Smaller is probably better in this case since the screen is very readable
Battery	User replaceable AA (kinda)	Potted, Lithium, Rechargeable	All AA batteries do not work well in the VR3
Physical Interface	Buttons tend to stick. Long hold / Short Press	Tap. Can be too sensitive and get selected by mistake
Display	Readable, adequate	Very bright	Older eyes tend to prefer the color VR3 instead of the monochrome version
Deco Algorithm, Muti-gas	Buhlman standard (VPM available with additional license purchase). Time tested implementation with great record. Trimix with additional software license	VPM or Buhlman GF. Time tested in V-Planner but fairly recent in V-Planner Live. Trimix & Nitrox.	VR3 is know to be very conservative, too conservative possibly
Support, firmware/software	No repair center available in the North America. Must ship to the UK. Firmware/software not user updatable. Health check with Firmware Update is $199.95 !!!	Ship back to the manufacturer in Canada for any issues. Firmware/software is user updatable	Of course what works for me in the US wouldn’t be ideal for a Europe or Asia based customer
Configuration of gases, bailout, dive parameters	Most difficult	Very easy	But some people don’t care about UI
Interface to computer	Antiquated software (no really, Windows 3.1 style), some can never get it working. Windows Only. Requires separate cable and license purchase	Out of the box, USB. Windows only. Integrates with V-Planner family	Being able to download your dives easily has become a requirement, I believe.
Rebreather usage	Fixed PPO2 (requires license purchase) or PPO2 monitor (One cell only, requires separate cable and license purchase)	Fixed PPO2 or PPO2 monitor (3 O2 cells + 1 CO2 – requires purchase of X-Link module)	The VR3 always read the 4th cell higher than the Harmmerhead read cells 1,2,3. Looking forward to monitoring cell 1,2,4 with the X-link module on the X1

Cost

As we can see the cost of the X1 and VR3, set up for external PPO2 CCR VPM Trimix deco diving are very similar (and outrageous):

	Delta-P VR3	Liquivision X1	Shearwater Pursuit
Base Unit	$1474	$1750	$1195
VPM	$290	$125 (V-Planner Live)	N/A
Trimix	$200	built-in V-Planner	$250
Download Support	$230	comes with unit	comes with unit
CCR (Constant PPO2)	$100	comes with unit	$250 *
CCR (PPO2 sensor support. no cable)	$225	$675	$250*
Total for CCR setup	$2519	$2550	$1745 (No VPM, pre-configured)*

* Shearwater Pursuit is $1745 if bought pre-configured as Trimix w/CCR External PO2 Unlock

Conclusions

The Liquivision has performed flawlessly for me. The combination of a great hardware platform with a great implementation of V-Planner on a dive computer is a killer combo. I have been diving the X1 as a backup first (with the Harmmerhead and the VR3) but since my VR3 failed again halfway through my trip it became my secondary deco computer quickly. I really look forward to the X-Link which will allow me to monitor 3 cells (1,2,4) and get deco information based on actual PPO2 throughout the dive. One might think that my opinion is biased by my dislike for the VR3 but don’t be fooled, the X1 really is the next generation of dive computers and I highly recommend it.

In an earlier post, a commenter said the following:

Why would anyone give a fuck about the interface

My response:

Because if I can’t remember from trip to trip how to do things on [the deco computer], all other aspects of the computer are irrelevant. If it takes forever to configure my bailout gases, calibrate, change any settings, it’s not a good interface therefore not a good computer, that’s why ? Is the interface irrelevant in Windows, Mac OS X ? No, it’s the most important thing for desktop operating systems. Here you have a device which you have to manipulate often, sometimes in very stressful situation (bailout…), in the water, with dry suit gloves on, in current. The interface has to be stellar, it’s a key component. Lots of people like to follow the bouncing ball with the VR3 but with the arrival of Shearwater, Nitek X and X1, they no longer _have_ to.

Also, and though all of my diving with the X1 was on a rebreather, the computer would perform equally wonderfully as an open circuit deco computer.

What’s next ?

I haven’t gotten my hands on the X-Link (PO2 module for the X1) yet so look forward to a review together with the new version of V-Planner Live. I would like to get my hands on a Shearwater Pursuit (which comes highly recommended and can be configured as a solenoid controller), Dive Rite Nitek X and an OSTC soon as well. I also look forward to trying out the new Delta-P VRx which I am hoping corrects many of the user interface issues I found on its older sibling.

Coming soon as well is an article by Soggy on why he doesn’t dive with a deco computer.

Underwater Pompano Beach through a 14mm lens

Twain — Wed, 26 Nov 2008 04:59:43 +0000

I usually dive with a Canon G9 in a Canon factory underwater housing. It’s a great all-around underwater setup with one primary limitation: you can’t get wide. The G9 has a max width of 35mm and the factory housing doesn’t have the ability to modify that via an external adapter. Normally 35mm wide is just fine for the 15ft visibility we have up here in Boston – you can’t see much anyway! But for our FLL trip I wanted to bring in some heavier artillery and see what kind of damage I could do.

Off Erik I bummed his Canon 5D. I then hit up the family pro for an underwater dome housing and slapped a fat Canon 14mm type-L lens on the 5D. Nice. Locked and loaded.

Note – just pictures here. For a writeup of the trip go read Erik’s post.

I love the overhead light on these compartments in the Sea Emperor. They blow out like flourescent bars. The giant concrete cylinders made for great foregrounds to anchor the bottom of the wide lens.

I really like the look Brandon @ DownTooLong gets from some of his shots in greyscale. I gave it a try here by choosing a few of the Sea Emperor shots that were monochromatic green and swapping them to monochromatic grey in Aperture, with a few tweaks.

This ray did a drive-by so close he had to wrap his wing over the camera to get by me. Keep in mind this is a 14mm lens. If it looks 10 feet away it’s 10 inches. If it looks like 6 inches, well, it’s actually 10 .

These are from the Hydro Atlantic. She was the only ship we dove which was not a purposeful sinking. You could tell from the sheer amount of wreckage on her decks. I like the first shot because once I tweaked it in monochrome you could just barely see our two buddies (Tom M & his partner) coming down the line.

The Spiegel was wonderful. Such a nice wreck do explore. I’m a real buoyancy fanatic (snob?) and it was a fun exercise to meander slowly through and up and down four decks all without touching down into the silt. This is me (photo by Erik) on the right; Erik in the photos below did quite well maneuvering with his video cam while still holding buoyancy.

On our second Spiegel dive we did a nice outside tour. I have a thing for propellers and we checked out the portside prop, but I didn’t quite get the shot I wanted. On the way back out I framed a couple long-distance shots, one of the crane and one of Spiegel’s bow beneath us (with Tom M. and his dive buddy visible returning to the line). The 50+ ft viz made distance shots nicely possible.

Cold Water Diving

soggy — Mon, 24 Nov 2008 16:08:04 +0000

The time has come where, at least here in the frozen wasteland of the northeast, we are diving with air temperatures well below the freezing point and often with wind chill factors below zero. This, compounded with water temperatures in the mid to low 30s can have serious consequences if we don’t take care to dive with the proper equipment and procedures. Regulators can freeze, hands rapidly become numb, and hypothermia can set in quickly if diving wet or with a leaking drysuit. There are several equipment and procedural techniques we can use to help combat these problems.

Equipment Considerations

Exposure protection

Dive dry. While there are many high-quality wetsuits available and cold tolerance varies from individual to individual, a well maintained drysuit with a proper undergarment will keep you warmer for a longer period of time. Hypothermia is extremely dangerous. It slows the thinking process down and also is a major contributor to decompression-related injuries.

Wear a proper undergarment under your drysuit. A proper undergarment is a garment made out of a warm material that, in the event of a flood, retains most of its insulation value when wet. 3M?s Thinsulate is an example of this kind of fabric and it retains over 80% of its insulation value when wet. Most manufacturers make Thinsulate lined undergarments including DUI, Viking, Diving Concepts, Bare, and Andy?s. In the winter months, adding a thin wool or polypro layer underneath the drysuit undergarment can help wick moisture away from your skin and keep you much more comfortable during the dive. Personally, I wear a thin Under Armour long sleeve, compression fit shirt . Do not wear cotton in the drysuit. Cotton is a horrible insulator when wet and will actually hold the water against your skin, which when combined with a drysuit leak will quickly lead to hypothermia.

Wear dry gloves. Just like a drysuit will keep you warmer than a wetsuit, dry gloves will keep you warmer than wet gloves. It is important to use a dry glove system that allows you to keep the inner seal intact in case you get a leak in your glove. Without a wrist seal, a small leak in the glove can rapidly lead to a very wet and cold dive. To equalize the gloves, slip a long, thin piece of surgical tubing or shock cord underneath the wrist seal. When possible a hands-off approach to diving is the best way to prevent a leak from developing.

Regulators

Dive with a 1^st stage diaphragm regulator that is environmentally sealed. As a general rule, diaphragm regulators are less prone to freezing problems than piston regulators. An environmental seal prevents water from entering the chamber and freezing.

Use a ?downstream? regulator. Downstream regulators will universally freeze in the open position, free-flowing the regulator. While this means loss of gas until you can shut down tank, it also means you have gas to breathe until you can switch to an alternate gas source. Some ?upstream? regulators can freeze in the closed position, suddenly depriving you of gas to breathe. Most regulators manufactured today are of downstream design, with the exception of a few such as Poseidon, which are upstream. Poseidon regulators have an over pressure valve that helps reduce the possibility of lock-up, but my opinion is that it is just another part that can fail when a simpler design works just as well.

Always have a redundant gas supply in case the regulator freezes. Redundancy comes in many forms including a good buddy, doubles, or a pony bottle.

Procedures

Even if it?s going to be above freezing on the day of the dive, keep your tanks indoors the night before. The pressure drop from a tank pressure of 3000 psi to the regulator?s intermediate pressure of 140 psi causes a phenomenon called adiabatic cooling. This can cause a temperature drop of up to 40-50 degrees. If the gas in your tank is at room temperature, the gas you end up breathing is likely coming out at 20 or 30 degrees. Now consider that if your tanks have been sitting in a car overnight, the gas in the tanks might be 10 or 20 degrees. This means, due to adiabatic cooling, the gas you are breathing is 30 or 40 degrees below zero. Not only will this chill your body from the inside much faster, but it will also greatly increase the likelihood of regulators freezing.

If the outside air is below or near the freezing mark, before the dive, do not exhale into the regulator until both the first and second stages are submerged. The moisture in your exhaled breath can collect in the second stage and cause freezing before you even get in the water. This means when you test breathe your regulator, only inhale through it; do not exhale back into it. It is also advisable to even minimize breathing from the regulator at all until it is submerged.

Plan your dive with the assumption that gear will leak and regulators will freeflow.

Plan your dive times shorter. It isn?t enough to say, ?we?ll turn around when one of us gets cold.? By that time, it?s too late. You are now uncomfortably cold and may have a long swim and ascent remaining which equates to getting closer and closer to hypothermia.

Be more conservative. That tough dive you did last August suddenly becomes a whole lot more challenging when it?s 15 degrees outside and the water temperature is 36 degrees.

Conclusion

Make sure you are well prepared before embarking on that cold-weather, cold-water dive. Using the right equipment and procedures can do a whole lot to mitigate the risk of this type of diving.