What’s involved in a trimix course?

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Southwold Wreck Stern Malta

Southwold Wreck Stern Malta

Having just completed another excellent trip out to Malta I thought it might be useful to write a short post about what’s involved in completing a trimix program. There are plenty of articles out there about trimix but essentially it’s a mix of Oxygen, Nitrogen and Helium. The helium content allows greater depths because it allows you to reduce the O2 exposure, which in air hits a max P02 of 1.4 at 56m, and also reduces the nitrogen exposure which obviously causes narcosis at greater depths.

There are 2 levels of Trimix certification under the PADI system: Tec 65 and Tec Trimix. To enter either of the programs you need to be PADI Tec 50 or equivalent, rescue qualified and have a 150 logged dives

Tec 65 essentially equates to a Normoxic Trimix certification which means that you are only qualified to use a trimix that is breathable on the surface, minimum 18%. As you might guess from the name, the depth limit is 65m….

Tec Trimix is the full trimix ticket and allows an unlimited depth certification using hypoxic trimix to reach depth.

What’s involved in a typical program?

The first day will usually cover skills, theory and kit setup. If you’re entering a trimix program then you’re already tec certified and will (hopefully) have some degree of experience. You’ll probably have your own kit and be used to diving it. Therefore the kit configuration part of the trimix program doesn’t tend to get too focused on issues like wings and harnesses but is more concerned with the extra equipment you’ll be carrying. I don’t tend to lose my sh*t over whether people have bungeed wings or breaks in their harness (I personally advocate a harness break for open water diving) but I will look at some of the smaller details (like D ring positions) because the main equipment challenge for trimix courses comes from dealing with multiple stages. Another new piece of kit is the suit inflation bottle which whilst not essential is a far neater way of running a drysuit that coming from a stage. (trimix isn’t great to use as a drysuit inflation gas as you tend to get rather cold…).

The shallower skills dives for trimix also cover ground that you’ll have hopefully covered before: Shutdowns, gas sharing and SMB as well as team awareness and positioning. There’s a few extra things thrown in, including a stress test where you’ll remove and replace 4 stages without your mask (it’s fun-honest) but given that you will now be dealing with multiple stages and gas switches there is an even greater emphasis on ascents, team positioning and handling stages. One of the nice things about a trimix cert is it will make carrying one or two stages seem like a doddle!

The next couple of days will usually bring another skills dive and also some deeper warm up dives. The first official deco dive will just be run with 2 stages to ensure that you are comfortable racking up some deco and managing a couple of gas switches. If you’re heading to Tec 65 you’ll stick to diving with 2 stages, but if you’re heading for full Tec Trimix then we’ll add a third stage after this even if it’s just to carry for practice at first. There are a couple of methods for handling a third stage including using a leash but you’ll soon find it fairly straightforward

As the dives progress, much of the dive planning will be handed over to you. Dive planning for tec doesn’t have to be massively complicated, but you do need to ensure that you cover all your bases. There are various tips and tricks you can use to make dive planning more straightforward and we’ll discuss these as well as other things like gas choices, deco software etc.

As the dives increase in depth we’ll start to introduce various emergency scenarios into the dives for example you might be given the signal that your computer has failed requiring you to switch to written plans and complete the dive with the team or you’ll need to respond to a lost gas during the ascent.

In total you’ll be looking at around 5 dives for Tec 65 over 4 days and 7-8 dives for Tec Trimix over around 5-6 days.

Where can I do it?

In Malta there are some really quite phenomenal wreck dives that can be done as part of the program. During our week we diving the Stubborn, a British WW2 sub lying upright in 55m of water, The Southwold a British destroyer that hit a mine and now lies in 2 separate parts. The stern section is a particularly great dive as the wreck is still littered with shells, depth charges, bottles, toilets and the name of the wreck still visible on it too. We also dived the Polynesian which is a huge passenger ship torpedoed in WW1. All these wrecks are untouched with loads of artifacts still viewable on them.

In Croatia there are more brilliant wrecks. One of the highlights is the SS Viz a huge cargo ship that hit a mine and also the Argo which lies in 2 sections, diveable on the same dive both which lie in around 60m max depth

What about costs?

Although trimix programs can be run in the UK I tend to like to run them overseas as I think you get a bit more enjoyment for your gas bill! Tec 65 can be run in Croatia and Malta whilst full trimix is better run in Malta where you have easy access to depth. Gases are undeniably an expensive part of this program but also tend to be cheaper overseas. Croatia is particularly good value for gas but Malta is also inexpensive. As a guide Divewise charge approximately €750 for 5 days of boat diving including basic equipment hire and all gases which is exceptionally good value. My most recent trip to Croatia saw the gas bill come in at around €250 euros per person for 4 days of trimix diving. So the gas bill isn’t inconsequential but it doesn’t have to be terrifying either! On top of that you have course fees and any other costs like flights and accommodation.