Trimix Deep Dive Prerequisite

[Tigerpaw]

For the upcoming year I will be taking additional Technical Diving courses. One of those classes is the TDI Extended Range/Trimix combo class. One of the prerequisites for Trimex is that you need 25 dives at 100ft or greater. I currently only have 9 dives. I'm planning on knocking out the remaining 16 dives but then I thought to myself, "What is the best way I can utilize those 16 dives?" In other words what should I be doing or practicing that will benefit me as a diver at that depth? I'm thinking anybody can teabag 16 dives, but I'd like to make the most of it. As always thanks in advance!

 

[PEDiver]

If you're already AN/DP certified, maybe do some practice dives with stage/deco bottles since bottle proficiency is important for the class. Could also throw some DSMB practice in there as well. You can also use those dives to work on trim/buoyancy and make sure your kit and configuration are on par with what you will need for the class. If you're not tech diving regularly, some of the skills like bottle manipulation might sneak up on you if you haven't done them in a while (same for deploying a DSMB since you'll probably have to deploy one in the class while also solving another problem like OOG).

 

[Miyaru]

Don't look at just the number of dives, knocking down numbers is not equal to gaining experience.

It never hurts to measure your SAC/RMV rates again. You will need it for planning anyway, and you might see some experience progress.

 

[inquis]

Holding precise stops is arguably one of the hardest skills. I suggest NDL dives with practice stops starting at 70 ft/21 m for 2 minutes. Increase the time by a minute each stop.

Use a DSMB on every ascent, but don't hang on it -- just OK the line while at a stop. Count the number of times you drift up/down and can't touch the reel/spool. I don't know the exact standard you'll be held to, but I'd bet it's less than the length of your arm. (I.e., shoot for zero.)

(Obviously, the DSMB will be flat when doing it this way. Let your buddy lightly hang on it if it needs to be vertical.)

You will probably also want a reel for the eventual deployment from deeper depths. (Spooling up 200+ ft of line gets a bit old.)

 

[lermontov]

find a safe and easy accessible spot at around 6-10m and practice all the base skills like bottle manipulation and shooting an smb valve drills etc -make a list

then when your more comfortable go do a dive -repeat

 

[Miyaru]

find a safe and easy accessible spot at around 6-10m ....

He asked what to do at 30m/100ft.....

 

[GF99/99]

For the upcoming year I will be taking additional Technical Diving courses. One of those classes is the TDI Extended Range/Trimix combo class. One of the prerequisites for Trimex is that you need 25 dives at 100ft or greater. I currently only have 9 dives. I'm planning on knocking out the remaining 16 dives but then I thought to myself, "What is the best way I can utilize those 16 dives?" In other words what should I be doing or practicing that will benefit me as a diver at that depth? I'm thinking anybody can teabag 16 dives, but I'd like to make the most of it. As always thanks in advance!

Practice diving with two S80 stages so you get really comfortable with that. I know for some people this can be a little overwhelming, handling them, kitting up on the boat, diving with them, un kitting after the dive, getting the rigging setup for you, etc. Being very proficient at this will take one less thing off you mind and it will become second nature.

For skills at depth, practice buddy rescues from depth. This is probably the most difficult skill and takes a lot of practice. If you have a dive buddy that is willing simulate bringing him up from depth. As others have mentioned being very proficient at holding stops with good buoyancy is key to high levels of diving. Now throw in the fact that you have to control your buddies buoyance as well (and if your diving dry that is 4 gas sources you have to control).

Depending on your ANDP course/instructor and how well they pushed you/prepared you I have seen lots of ANDP divers that just get cranked through there ANDP and do just the bare minimum agency standards with a little S40 stage (and of course not rigged properly) and very minimal deco stops all while hanging on an SMB.

 

[SpeedyJ]

I think building the capacity to create and execute a planned dive is key - there is a difference between actively managing a dive vs. just watching your SPG and no-deco limit.

I use the 5-min segments approach. If you have good knowledge of a dive site or a good guide book, build out a dive plan with waypoints that are ~5 min apart, be there when you say you are going to be with the amount of gas you should have - for a wreck dive it might look like this:

• Descent & stabilize: 5min: 3300psi
• Swim aft 150' port rail to pilothouse door: 10:min 3050psi
• Entry to engine room: 15min 2825psi
• Explore engine room: 20min 2500psi
• Exit engine room hatch swim 75' to forward cargo windlass: 25min 2200psi
• Swim 75' to mooring line, stabilize, begin ascent: 30min 1950psi

 

[lermontov]

He asked what to do at 30m/100ft.....

yes quite right - although he's only done 9 dives at 30m so id still recommend any practice in the shallows

so maybe an idea would be as @SpeedyJ suggested -map out a plan and see how close you can get to executing it

 

[happy-diver]

I suggest to the nervous ones on the boat to pretend they're doing a 10m dive

After realisation the apprehension lifts