Check Your Trim!

Why I’m obsessed with cylinder trim?

“In the beginning, God created Sidemount …”

When I first started diving sidemount I observed a weird phenomenon on my dives;

Dive 1: Perfect – Cylinders are in the right place, body is in the right position. I feel great!

Dive 2: Nightmare – Cylinders are now misbehaving, where’s my body? Everything feels…off!

Then God said – “let there be light!”

This pattern of frustration continued until I learned that cylinders can’t just be clipped off and left for dead. Even steels change buoyancy. Just not as drastically as Aluminiums. Eventually, I got an education in D-rings and studied the personality of my cylinders, which behaved in an interesting but fairly predictable way! As I breathed them down I could trim them out and feel good every dive.

And God said, “Let the water teem with sidemount divers, and let them glide across the seabed.”

Nowadays, Ali’s or steels, I can’t stand or accept the feeling of my tanks being out of trim. If I haven’t set my D-Rings correctly I can tell instantly and have to reposition them before I can relax. Why is that? There are no laws stopping me from diving with my tanks at 90-degree angles or dragging underneath me. It’s not sidemount though, is it? It just feels wrong. It feels unbalanced and it gets unnerving when you turn and your tanks follow half a beat later because they’re not configured properly. Throughout the dive, adjustments are made to maintain a streamlined horizontal trim, gliding – not fighting – my way through the water.

Finally, God saw all that he had made, and it was very good

In the end, it comes down to feeling good, looking good and diving safe. I know that the more streamlined everything is, the better I feel and the better I dive. There are many excellent articles and videos out there explaining the intricacies, measurements and physics of diver trim – essential knowledge for getting the ‘how’ as well as the ‘why’.

So next time you’re diving remember my mantra:

‘Check Your Trim’