Tag

Technical

Dive Propulsion Vehicles (DPVs)

By | Gear | No Comments

There are a number of great Dive Propulsion Vehicles (DPVs) available. I personally love my Dive-X CUDA 400. If I had more loot when I bought my scooter, I’d probably have an 1150 just for the increased run time. I rarely use what I have, but when you’re trying to plan thirds, a CUDA 1150 sure gives you plenty of time. Then again, you should probbly just drag along a second CUDA 400. But I digress…

There are a lot of options when it comes to scooters, with different trade offs based on the money you’re willing to spend, the scooter size & weight, battery chemistry (NiMH, LiPro), and range desired.

Depending upon your application, some scooters may be entirely out of the running (e.g. a Dive X Sierra doesn’t provide you very much range, therefore isn’t a great cave scooter.)

Scooter Benchmarks

The Tahoma Benchmark Tests are your best bet for raw data. Each year different scooters were tested, so if you’re trying to read up on all of them, you’ll have to read all three reports.

My recommendation would be to find a friend with the scooter you’re interested in diving, and dive it.

While I love my CUDA, everyone that spends $2500+ dollars on a tool loves the one they selected. So asking people which one is best isn’t going to yield you too much of a delta from simply looking at the scooter they purchased already.

Scooter Manufacturer Links

Pacific Northwest Dive Clubs and Groups

By | Resources | No Comments

Online dive forums and resources can be a great source of information and help you get excited about learning new techniques, exploring new dive sites or areas, and meeting new dive buddies.

Always remember that people’s opinions vary, as does their actual experience and knowledge on a subject..so just be aware of that as you get advice.

Recreational Forums

  • Northwest Dive Club: Local pacific northwest focused dive forum. Lots of folks talking about diving, good place to find regular local dives.
  • Scubaboard: Scubaboard covers recreational diving all over the world. Need advice on diving in the Caymans, they’ve got a sub-forum for that. Want to know about diving in Fiji, no worries…they have a Pacific Islands Forum too.

Technical, Rebreather & Cave Forums

  • The Deco Stop: A forum focused on technical and cave diving. Great info and a wealth of info, but comments can get snarky for novices asking questions who haven’t done their research independently.
  • Rebreather World: Community focused on rebreathers. Great place to learn and ask questions about rebreathers.
  • CCR Explorers: Rebreather focused forum, also heavily leaning toward cave discussions.
  • Cave Diver’s Forum: As the name implies, all about the caves.

Local Groups & Clubs

Archaeological & Exploration Teams

Other Great Local Technical Training

PB4Y Privateer

By | Dive Sites | No Comments

One of my favorite local tech dives is the PB4Y Privateer in Lake Washington, which I affectionately call just “the bomber”. It sits in roughly 150′ and is only about a 15-17 minute scooter ride from Warren G Magnuson Park.

This is NOT a tech-reational dive, nor one I’d do on deep air. The lake is dark, not like a night dive… like I put a bag over your head. This tends to increase narcosis greatly 🙂

Additionally the “bottom” of the lake is very fine grained silt. If you manage to kick it up (or lawn dart into it from a boat), plan on the silt cloud obscuring visibility for quite some time (easily an hour +).

The entrance is just North of the boat ramp (the next turn in the road).

PB4Y Shore Diving Entrance

PB4Y Shore Diving Entrance

Here is a typical dive profile diving the wreck from shore. This is a CCR profile, on doubles I would dive 21/35 + 50% for deco.

PB4Y Dive Profile

PB4Y Dive Profile

There is a ton of great info and videos available from local wreck divers on the PB4Y:

As always with any dives: be safe, be prepared and don’t dive beyond your limits.

SS Admiral Sampson

By | Videos | No Comments

I had the pleasure of diving with the guys from Maritime Documentation Society (MDS) on the SS Admiral Sampson for two days last week. What an amazing wreck!

Quick stats:

  • 296 feet x 36 feet
  • Born: December 1898
  • Sunk: August 26th, 1914
  • Lies in 320 fsw off Point No Point

Day 1 Diving

~ 8 minutes on the bottom (turned for severe current and equipment failure)

Day 2 Diving

~18 Minutes on the bottom (planned bottom time of 20 min), 120 min total run time.

Other Resources

For some great historical research and much more polished (awesome) videos, see the work of Dan Warter with DCS Films:

Standard Gases

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I often get asked how do you know what mixes of bottom gas to take on a dive? There are two schools of thinking here, Best Mix for the dive or Standard Mixes for a variety of dives.

Essentially Best Mix means you calculate the mix based on the planned depth of the dive. So for a dive to 130′ fsw, at a PPO2 of 1.4, not getting into the narcotic gases and deep air arguments you will undoubtedly hear, the best mix is 28%. For 120 fsw, it’s 30%. You use Dalton’s Diamond to figure out the mix for the depth you want and you mix it.

When I started technical diving, I followed the best mix philosophy. While I still think for a given well planned dive, it works very well and can shave off some deco time… logistically it’s not as easy to be prepared to do a variety of dives. You need to plan the dive and get the fill for that specific dive. With standard gases , you can have a few sets of tanks available to do a wide variety of dives. This is even more true when you get into rebreather diving and bailout tanks, but that’s another article.

The standard gases philosophy is promoted by some of the largest Doing it Right / Dive it Right (DIR) agencies. While they still have a few practical differences between their standards, and if you search the web historically they’ve had even more changes over time… the basic gases are very similar, if not the same.

Below I’ve listed the UTD Standard gases. You can also check out the WKPP Approved Gases page for another nice view of this data (albeit slightly different as it’s GUE, not UTD).

Bottom Gases (Average PPO2 of 1.2)

Gas     ->  Working Range
32%    ->  0′-100′
25/25 ->  90′ – 130
21/35 ->  100′ – 160′
18/45 ->  160′ – 200′
15/55 ->  200′ – 250′
12/60 ->  250′ – 300′
10/70 ->  300′ – 400′

Deco Gases (PPO2 = 1.6)

Gas     ->  Working Range
100%  ->  20′ – 0′
50%    ->  70′ – 30′
35/25 ->  120′ – 80′
21/35 ->  190′ – 130′
18/45 ->  240′ – 200′

Oxygen Breaks

  • UTD: 10 Minutes On / 5 Minutes Off
  • GUE: 12 Minutes On / 6 Minutes Off

Interesting Rationale on selecting these mixes as Standard Gases from a thread with AndrewG (head of UTD, previous training head of GUE):

Look at the original criteria for standard mixes in order of importance:

  1. Must be able to partial pressure blend by adding helium and then topping with Nitrox 32% at a local dive shop
  2. Must have a low PPO2 at it’s max operational depth. 1.2 or less
  3. Must have a buffer zone for safety. If you need to rescue someone or go deeper then there is a buffer.
  4. Must have a narcotic equivalent depth of 100′ or shallower based on the conservative formula of (1-he)*ata”

Required Tec Diving Equipment

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Intro to Tech Diving / Discover Tec Diving

1 Back Plate & Harness (Stainless Steel or Aluminium)
1 Back Inflation Style Wing

1 Set Double Steel Cylinders with Isolation Manifold (100+ cu ft recommended)
2 DIN Regulators (Double Cylinder Configuration)

  • Hose Config:
  • 7 ft. Primary Regulator Hose
  • 22 or 24″ Necklace Regulator Hose
  • 24 or 26″ SPG hose

OR
1 Single Single Steel Cylinder (100+ cu ft recommended)
1 DIN Regulators (Single Cylinder Configuration)

  • Hose Config:
  • 7 ft. Primary Regulator Hose
  • 22 or 24″ Necklace Regulator Hose
  • 24 or 26″ SPG hose

1 Primary Mask
1 Back Up Mask

1 Pair Non Split Fins (Spring Straps Recommended)
1 Drysuit (with 2 Pockets, 1 Per Leg, Recommended)

1 Compass
1 Dive Computer (Depth & Timing Device)
1 Set Wet Notes or Slate

1 Surface Marker Buoy (SMB)
1 Finger Spool or Side Handled Reel (100′ minimum)

1 Cutting Device
1 Primary Light (Canister Style Recommended)
1 Backup Light (2 Recommended)

TDI – Advanced Nitrox & Deco Procedures | PADI – Tec 40, 45, 50

Intro to Tech Required Elements PLUS:

1 Aluminium 40 (AL40) or 80 (AL80) deco bottle (O2 Clean)
1 DIN Deco O2 Clean Regulator with 40″ reg hose and 6″ spg hose

1 Canister Light
2 Backup Lights

1 Additional Depth & Timing Device (e.g. Dive Computer)
1 Additional Cutting Device (1 Accessible from Both Hands)
1 Side Handle Reel (200′ minimum)

Trimix Courses

Tech Required Materials PLUS:

1 Aluminium 40 (AL40) or 80 (AL80) deco bottle (O2 Clean)
1 DIN Deco O2 Clean Regulator with 40″ reg hose and 6″ spg hose
1 Lift Bag (80lbs minimum lift, Closed Circuit Recommended)
1 Side Handle Reel (400′ minimum)
1 Drysuit Inflation System (Argon Bottle + Reg)

Decompression Procedures Manual

Deco Procedures Diver

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As sport divers planned decompression is not something that we do or have been taught. The TDI Decompression Procedures course prepares you for planned staged decompression diving. With a maximum operating depth of 45m/150 feet, this course is your first step beyond the normal sport diving limits.

Your TDI Instructor will provide you with valuable information and skills, among the topics covered are:

  • Kit set-up
  • Equipment requirements
  • Decompression techniques
  • Decompression breathing gases
  • Gas management
  • Contingency planning
  • Problem solving procedures

The TDI Decompressions Procedures course combined with the TDI Advanced Nitrox course form the foundation of all other technical courses.  After these two courses and some additional experience, the stage has been set for you to move onto additional technical levels.

Some of the materials you will be using include the TDI Divers Guide to Decompression Procedures, US Navy or Buhlmann Air Decompression Tables (made of vinyl for easy in-water use and storage)

Advanced Nitrox Manual

Advanced Nitrox Diver

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The TDI Advanced Nitrox Course qualifies divers to use enriched air nitrox from EAN 21 through EAN 100 within your current certification level to a maximum depth of 40 metres/130 feet during dives hat do not require staged decompression. Often taught in conjunction with the TDI Decompression Procedures course, this can be considered the foundation of your technical diving career. Advanced Nitrox is also a great course for those wanting to extend their bottom times in shallower depths such as scientific diver, and a must for SCR or CCR divers. The course cover topics like

  • Equipment requirements
  • Dive planning
  • Oxygen tracking
  • Blending methods

You will use the TDI Advanced Nitrox Diving manual for your course, which explains in an easy to understand practical manner the complex information that Advanced Nitrox divers need to know.