Saturday, 8 June 2013


I have always disliked wearing wet suits: apart from cosmetic reasons, putting on a soaked wetsuit is probably my pet hate.  So much so that my diving destinations are either 30 degree Celsius water bikini diving or heaven forbid, a dry suit in the red sea during winter months.

After booking myself for a week of diving in Florida Keys during May, I realized water temperature of 26-27°c was too cold to be bikini diving, especially doing up to 4 dives a day.  I looked round and found the Fourth Element Thermocline range, a neutrally buoyant wetsuit.  I bought the Thermocline Explorer, which is a sleeveless one piece.  In addition I also purchased the Thermocline Women’s Shorts and Women’s Short Sleeve Top.

I wore a rash vest underneath the Thermocline Explorer and Women’s Short Sleeve Top over.  It was cosy and easy to put on.  The fleece layer was comfortable on land, without feeling too hot when kitted up (yes even in the tropical Florida Keys weather in May).  Underwater at 26 degree Celsius I was snug and the garment also flexible range of moments. 

In the afternoon dives I opted for my rash vest with the Women’s Short Sleeve top and Women’s Shorts.  The best thing I like about the Thermocline range is the rapid drying.  No ‘wet’ wet suit!  It is light to pack, important with the luggage allowance for travellers.  It is also machine washable, nothing beats a fresh smelling suit!  In addition, it can also be used as an undergarment for a dry suit.  One improvement that I would suggest is perhaps the Thermocline Explorer could have a “foot strap” or “stirrups” that could keep the hem from occasionally riding up.  I think I would complete my collection with a new Thermocline Women’s Long Sleeve top. 

PS: Not currently sponsored by Fourth Element, but would love to be!

The boring bit!

All opinions expressed in my articles are my own and may differ to other instructor’s and agency guidelines; by no means are they wrong and I would not wish to disrepute any of them.  This article is for information only and should not replace proper training.

Safe diving!

Henrietta Poon
BSAC, PADI and SDI/TDI diver training
l Mob: 07968148261 l Email: l

Wednesday, 5 June 2013


The Shearwater Petrel is the fifth dive computer I’ve owned.  Previously I had 2 Suuntos; a Gekko when I started diving and a Vytec DS when I started accelerating my deco.  I then moved onto 2 VR Technology VR3s when I started using mixed gas before purchasing the Shearwater Petrel.  What can I say, other than I’m sold on it.  Read my thoughts below.

Going back a few weeks, I was unfortunate enough to lose one of my VR3’s whilst diving in Plymouth.  Luckily my insurance offers a new for old replacement so once I knew I had a cheque coming to me I had some decisions to make.  Did I buy a direct replacement with the VRX from VR Technology or did I look for something different such as the DX from Suunto, X1 from Liquidvision, OSTC 2n or 3 from Heinrichsweikamp, or the Petrel from Shearwater Research?  On The Dive Forum (TDF) there were a couple of threads, mainly the OSTC v Petrel (here with mine here) as I wasn’t the only one with a difficult decision.  In the end I opted for the Shearwater Petrel (obviously).  The reason for this was that it is Closed Circuit Rebreather (CCR) and Semi-Closed Circuit Rebreather (SCR) compatible, most new CCRs that I would consider getting have a Shearwater controller (JJ-CCR, rEvo, SF2) so if I got a CCR it would run the same algorithm and the controller would be similar to use, according to users who have had both the Petrel and the 2n the Petrel appears simpler to use, I’m not a fan of a computer where you can write your own algorithm (2n), I prefer the Piezoelectric buttons found on the Petrel and the 2n opposed to the ones on the 3 and VRs and lastly I prefer a user replaceable battery as opposed a rechargeable one.

So once my decision was made I contacted John at Narked@90.  John was very friendly and helpful so as soon as the cheque arrived the purchase was made.  In addition to the Petrel I also ordered a spare set of battery O-rings.  Unfortunately I missed the last post Friday so it was dispatched Saturday and it was waiting for me Monday when I finished work.
When the box arrived the computer was very well packaged; there was no way anything was going to get damaged.


Inside the box.

Outside of the box.  The computer comes with a 1.5v battery fitted, a quick start guide, a CD with the manual and desktop software and 2x bungee straps (see later picture).  Personally I thought the quick start guide was a waste of time.  The manual is easy to read and understand, and it along with the desktop software and updates are available to download from the Shearwater Research website here.

How clear is the display?  The LCD with LED backlight is far better and easier to read than the LCD display on the VR3 and just as easy to read as the OLED found on the OSTC. 

Regarding the amount of information displayed, the left and right displays on the centre row are customisable to show average depth, max depth, @+5*, ceiling, GF 99**, CNS, clock, and expected surfacing time.  There are extra options for SCR and CCR or you can leave them blank to minimise the amount of information displayed.  If you do decide to turn the displays off you’ll not be missing any information as the user can cycle through the bottom row by pressing the right button.  When this is done all the previous information is displayed along with current gas, no decompression time, time to surface, current gradient factor, water temperature, tissue graph bar, deco model, battery status, time and date, serial number and version.  Although it may sound complicated, I assure you it is not.
*Predicted time to surface if you stay at the current depth for an extra 5 minutes.
** The raw percentage of the Bühlmann allowable supersaturation at the current depth.
The elasticated straps on the Petrel appear much safer than those I’d previously used on my VR3 as there is a locking mechanism on the adjuster to prevent it from coming loose.  The straps are more than long enough so I set mine up for my drysuit, left a small amount of spare end and then cut the remaining off.  I’ve also added an O-ring on each strap to keep the spare end tight against the strap; especially when wearing a wetsuit when the spare end is much longer.

The Petrel also comes with a bungee mount which comprises of 2 rubber inserts that get threaded through instead of the straps.  5mm bungee/shock cord is then added to this.  I have not tested these as I worry that the area around the eye could split if too much tension is applied.  I’m sure it won’t but it doesn’t look as secure as the metal one for the Shearwater Predator.

So how easy is it to use?  The menu system is much easier to use than my previous Suuntos and VRs and I was able to set the computer up without looking at the manual (although obviously I have).  Settings which required changing include salt/fresh water, date/time, metric or imperial, last decompression stop depth, breathing gasses, PO2 of gasses (dive and deco) and finally the Gradient Factor (GF).  I changed the factory setting  GF from 30/70 to 20/80 & now nearly mirrors V-Planner VPM-B with +2 conservancy settings (within 1-2 minutes total time, CNS percentage etc…).  I also have MultiDeco set on Bühlmann ZHL-16C (same algorithm as the Petrel) with the same GF so I can plan run-time slates.  The Petrel also has a dive planning function if you wanted to use it.

As previously mentioned, the Petrel comes with desktop software.  This software allows you to download your dives via Bluetooth and log them.  It’s very simple to do with most of the options available as a dropdown.
Additionally the software allows you to check for firmware updates for the Petrel and then update the computer via Bluetooth.

For the CCR owners, if you prefer your computer hardwired into your unit there is another version with a built in Fischer connector available.

Photo of Petrel post deco.

To summarise, the Petrel is a no fuss dive computer.  From navigating around the menus to logging the dives, the Petrel is very easy to use.  Despite not being OLED, the display is very clear and is very clear and easy to read, so much so whilst on my TDI Full Cave my instructor also bought one.  Best dive computer I’ve ever owned and used.

EDIT – 19 JULY 2015

For over a year now I have replaced the elasticated straps with bungee, initially using the rubber inserts (which I still have), but now opting to run the bungee directly through the delrin outer case. 

Although technically possible for the bungee cord to bunch up (this doesn’t happen with the rubber inserts (now discontinued apparently)), the computer feels secure to the wrist.  And donning/doffing is much easier. 

I have also changed the centre right display to constantly show the time, as I have found it far more useful when on the surface.

The boring bit!

All opinions expressed in my articles are my own and may differ to other instructor’s and agency guidelines; by no means are they wrong and I would not wish to disrepute any of them.  This article is for information only and should not replace proper training.

Safe diving!

Timothy Gort
BSAC, PADI and SDI/TDI diver training
l Mob: 07968148261 l Email: l