Claims made about ascending vertical vs horizontal

[Ted Judah]

Watch this:

The claim is that ascending vertically prevents your tissues from offgassing “evenly” rendering your stops completely ineffective.
I think flowstate divers is a great channel but this information seems fishy.

I’d love to hear an experts’ opinion on this - but I only have scuba board. So what say you?

 

[Endler's]

From Youtube comments: Scuba Safety Stop: What is safest?!

I concur.

 

[Bob DBF]

The claim is that ascending vertically prevents your tissues from offgassing “evenly” rendering your stops completely ineffective.

They should get that info to the NEDU before someone gets hurt.

 

[LFMarm]

I agree on the fact that tissue off gassing may be very similar between horizontal and vertical. However horizontal trim is the right position for both descending and ascending so that you can easily break trim slightly either way to use propulsion in order to change position in the water column. It also makes it easier to watch your team and stay close to them. Even offgassing may be a nice (small) byproduct.

 

[Brett Hatch]

Look, I'm an engineer, not a doctor, but that sounds like malarkey to me

 

[lowwall]

However horizontal trim is the right position for both descending and ascending so that you can easily break trim slightly either way to use propulsion in order to change position in the water column. It also makes it easier to watch your team and stay close to them. Even offgassing may be a nice (small) byproduct.

This is nonsense. Horizontal trim makes sense when you are moving horizontally through the water because it minimizes drag and keeps your feet away from surfaces and other divers. But it has no real advantages when ascending or descending. And, contrary to what you wrote, it has a clear disadvantage in field of view when ascending. Humans are built so that we have maximum effective vision when vertical. You are very limited as to what you can see above you when horizontal and even looking on your own level requires your neck to be rotated uncomfortably.

 

[LFMarm]

This is nonsense. Horizontal trim makes sense when you are moving horizontally through the water because it minimizes drag and keeps your feet away from surfaces and other divers. But it has no real advantages when ascending or descending. And, contrary to what you wrote, it has a clear disadvantage in field of view when ascending. Humans are built so that we have maximum effective vision when vertical. You are very limited as to what you can see above you when horizontal and even looking on your own level requires your neck to be rotated uncomfortably.

My belief is that the primary reason for horizontal trim during ascent/descent is the ability to manage position in the water column. Visibility and offgassing are secondary (or may even not exist).

 

[lowwall]

My belief is that the primary reason for horizontal trim during ascent/descent is the ability to manage position in the water column. Visibility and offgassing are secondary (or may even not exist).

OK, we can agree that if you need to move horizontally during ascent or descent, it's easier to do it from horizontal. But on a free ascent, or along a line in minimal current, it's easier and safer to manage when vertical because of the ease of looking up and around you. It only takes a couple of seconds to get horizontal if you need to go somewhere.

 

[steinbil]

But on a free ascent, or along a line in minimal current, it's easier and safer to manage when vertical because of the ease of looking up and around you.

I'll concede that it is easier to look up when vertical. However, I don't see the need to constantly look up during an ascent, and the small advantage that might bring I don't find to be enough to outweigh the advantages of being horizontal on ascent. Like you said, when moving horizontally, being horizontal minimizes drag. And when moving vertically it maximizes drag, which is exactly what you want on an ascent.

What is the most critical parameter of an ascent? Is it not the ascent speed and timing? Maximizing drag makes you more stable vertically, making it easier to control your ascent speed. Minimizing the effect of a horizontal current on your ascent is a bonus. On top of that, a horizontal position on ascent requires neutral buoyancy, which again means you are more stable and if you stop moving you will lay still - making it easier to deal with a problem that takes your focus without losing control of the depth.

 

[Etmutt]

Trim police alert !

“keeping trim during the whole dive” is just a completed invented way to show off by some diver.

being able to be horizontal is one thing. staying horizontal for the whole dive is just non sens. i don’t understand the visibility in the water column argument either. it is much easier to look up and down while being vertical, and the side vision is the same.