Jun 2015

Diving in Trim. Part 1

By Mike Waddington

Recently PADI has completed a huge change to the way that they teach the Open Water Diver course. Aside from adding a few skills here and there, the giant training agency has included lots of parts that you would expect to find in Technical Diving courses, such as gas management and dive planning. But probably the biggest difference is the constant trim checks that are required. Being ‘in trim‘ was something that only ninja tec divers could do properly, but finally the realms or technical and recreational diving are crossing, and newly qualified divers are learning in just a few Open Water sessions the importance of diving in trim. Having excellent trim in the water not only makes you look awesome, but it can also increase dive time, improve buoyancy control and even leave you feeling less exhausted after a dive.

What is Perfect Trim for Scuba Diving?

Having perfect trim means that the diver’s body is in a perfectly horizontal position. The diver should have their legs bent at the knees so that the fins are kept higher than any other part of the legs. The fins themselves should be kept parallel to the body. The arms should be extended in front of the body and the hands should be at the same level as the diver’s stomach. All the divers’ equipment should be streamlined against the body and nothing below the stomach line. The best way to describe the desired position is comparing it to the position a skydiver would be during freefall.


Why do I need to Dive in Trim?

Being in perfect trim allows divers to have far better control in the water. Being in trim makes controlling buoyancy much easier. As you have air in your BCD (normally) while diving, descending even slightly means the air inside the BCD will compress and you will start to sink. On the other side if you ascend slightly the air inside the BCD will start to expand, meaning you will also start to ascend, and perfect buoyancy is lost.

Many divers have still not perfected their breathing control as the main way to adjust buoyancy. Most common is divers who are always swimming pointing their body slightly towards the surface, which means their propulsion is actually controlling their depth control, not BCD or lungs, and as soon as they stop, they will start sinking. On the other hand there are many divers who have their BCD over inflated because they feel they have a tendency to sink. They constantly kick down to maintain position in the water, and as soon as they stop kicking they float up to the surface. Both of these diving ‘techniques’ create huge amounts of drag in the water, which means the diver is wasting energy and air.

The trim position also allows for much better control of the fins and opens the window for different propulsion techniques. When learning to dive many divers choose the classic flutter kick, because as a beginner it seems more natural. However after spending some time in the water the frog kick (breast stroke style kick) becomes more natural. Being in trim opens the window to other propulsion techniques such as modified flutter kick, helicopter turns and even back fining. The choice of propulsion method depends on the environment, but it is good to practice these as much as possible.

The Advantages to Diving in Trim?

There are many smaller advantages to diving in trim too. Because you as an individual have more control in the water, you can spend more time focusing on the rest of the team. A large percentage of accidents happen underwater because the leader is focusing too much on their own diving skills and forgetting about the rest of the group. When trim becomes second nature the only thing you need to think about is the rest of the team. Even things like searching for your SMB or reel should not take your mind away as you should already know exactly where things are and how to reach them. Once being in trim becomes second nature, you will find that most problems in the water become easy to deal with because now you only need to focus on the problem, and not your own diving ability.

How do I get Started?

To be able to master the art of perfect trim, first you need to get into the water! You should experiment with body position, weighting and equipment configuration. It is a good idea to practice with a buddy, who can tell you if you need to make any adjustments or fine tune anything. It is great if somebody can video or photograph you, as that way you can see what adjustments you need to make and how well you are evolving as a diver.

‘Diving in Trim. Part 1’ was written by Mike

Check out ‘Diving in Trim. Part 2

Tips and Tricks for the ‘Perfect Trim’ by TDI/SDI

Get the latest deals straight to your inbox.

Mike Waddington

I first discovered diving in 2008 after going snorkeling on the Great Barrier Reef in Australia. After trying diving at a flooded quarry in England I decided to head out to warmer more interesting waters in Thailand where I ended on the Island of Koh Tao completing my Open Water course. Instantly addicted with money to spend and plenty of time on my hands I decided to continue until I became a Divemaster so I could live what seemed as the perfect life.

After that I headed to the Caribbean to an island called Utila to complete my instructor course, I spent several months out there completing the MSDT internship, teaching students and leading dives. This is also where I discovered my interest in the technical side of diving, taking part in equipment repair courses and learning about blending gasses and running compressors.

With all my new qualifications it was time to head back to where it had all started, Back to Koh Tao where I intended on living the dream. Once I arrived I quickly found a job and started teaching straight away. During my time on Koh Tao I took part in all many technical diving courses, learning how to dive with re-breathers, in caves and even going down to 90m/300ft!


PADI Master Scuba Diver Trainer
PADI/DSAT Tech Deep Instructor
PADI/DSAT Gas Trimix Gas Blender
PADI/DSAT Trimix Diver
TDI Intro to Cave Diver
TDI Advanced Wreck Diver
TDI Inspiration rebreather Decompression Procedures
PADI Professional Videographer
BSAC Compressor Operator
TDI Equipment Service Technician

Dream Dive Locations:

Silfra, Iceland
Cenotes, Mexico
Chuuk Lagoon, Micronesia
Ice Diving in Russia