Why so much Horizontal trim ?

[Thalassamania]

Not wanting to highjack gcarters thread about trim so I started this one to ask, Why so much attention to strive to be perfectly horizontal when diving ? It seems some think it makes them look bad to others and tags them as a novice. Why is trim so important to some and how does it benefit ? I must be a Dork because my feet/fins are usually about 10/15 degrees high .

You're likley in pretty good trim them.

If you are horizontal, your body needs to push less water out of the way as you move forward. This means less effort, so lower air consumption rate.

Your conclusion is correct, however horizontal should be changed to direction of travel. If you are headed down at, say, 45 degrees, but are maintaining a horizontal body position, you're working too hard.

Another benefit to horizontal trim, that someone may have mentioned and I just missed, is it allows for better control of ascents and descents. Easier to slow yourself down by flaring, on either an ascent or the descent, and also, you can dump a significantly larger amount of gas, more quickly from the rear dump valve, than the shoulder valve, if you should need to halt your ascent quickly.

The neck/head tilt thing was a bit hard for me to adjust to at the beginning also, although I did come pretty close, even with my poor flexibility.

Ascent and descent should be controlled by maintaining good buoyancy control. If you need to increase your drag in the vertical, might I submit that perhaps some work on buoyancy is in order.

Trim is a tool. The "default" position should be horizontal, but there are times when it is fine not to be in that position -- for example, if you are drifting along a vertical wall, there's no particular reason to be perfectly horizontal (although if you aren't, it will be hard to back up if the water begins to push you into the coral!)

People have already mentioned both reducing the effort of swimming forward by presenting the smallest cross-sectional area to the water, and also not disturbing bottom sediments and reducing the vis. But there is another, more subtle and pernicious problem with being out of trim.

If you are swimming with your head up 45 degrees and you kick, where is your kicking pushing you? Forward . . . and UP. Each kick wants to push you shallower in the water column. So, in order to remain at the depth you want, what do you have to do? You have to produce a force downward that counters that force upward from your fins -- and you do that by remaining negative, so that if you stop swimming, you will sink. That leads to two things -- one, a significant part of your kicking effort is expended just to remain where you ARE; that's all breathing gas you used to achieve a net of nothing. Second, because you are not neutral, you CANNOT stop -- if you stop, you will sink. That makes inspecting small animals or getting good photographs very difficult, and in some cases, can lead to a great deal of anxiety on the part of the diver, who feels like he is sinking all the time. (Note that the exact same arguments apply if you are feet-up, as some wetsuit divers are, except that you have to stay positive instead of negative, but you still can't stop.)

Being able to stay horizontal and STILL is one of the core competencies of diving. Once you have a stable, flat platform, you can perturb it at will, knowing what you are doing and what the effects are going to be. But until you have that platform, you are constantly correcting some kind of instability, and it limits what you can do.

Lynne as it right ... anyone surprised? I'm not.

Trim may not be your issue. You might not have enough weight so you need to keep swimming down just to maintain your depth.

I tend to think of proper buoyancy as a factor in proper trim.

 

[spectrum]

Cosmographer,

I can appreciate what you say about neck comfort and panoramic views. Swimming a little farther for the bottom and learning to roll a little so you can pan your view will alleviate some of your issues while remaining trim.

Why?

1) If you are not level you are a wing driving yourself up or down. You can offset this with you BC.... until you pause.

2) When prone you "punch" a smaller hole in the water. You want to be an arrow, not a beach ball down there.

Pete

 

[Angry Turtle]

Watch this video, and see the effects of not keeping a horizontal trim

Awful - YouTube

WOW!,

I do not claim to be a trim master, but I don't think I could have managed 5 minutes filming him without blowing a fuse.

 

[Cosmographer]

I spend most of my dive time working on my photography, so punching efficiently through water is rarely a concern for me, but after being horizontal for a while (to get those shots), I like to ascend a few feet so I can go a little bit more vertical to give my neck a break. In fact, my favorite position for now is an upside-down one where I can maintain my vertical position while still getting close to the reef/bottom for pics - Of course, I do need to rotate my images afterwards, lol. I wonder if photographers have a slightly different take on trim? Eh, probably not - that would be too easy.

 

[Angry Turtle]

I spend most of my dive time working on my photography, so punching efficiently through water is rarely a concern for me, but after being horizontal for a while (to get those shots), I like to ascend a few feet so I can go a little bit more vertical to give my neck a break. In fact, my favorite position for now is an upside-down one where I can maintain my vertical position while still getting close to the reef/bottom for pics - Of course, I do need to rotate my images afterwards, lol. I wonder if photographers have a slightly different take on trim? Eh, probably not - that would be too easy.

My wife, the photog does spend a good amount of time upside down, it allows her to get real close without touching anything. Outside of that she spends her dive horizontally.

 

[spectrum]

I spend most of my dive time working on my photography, so punching efficiently through water is rarely a concern for me, but after being horizontal for a while (to get those shots), I like to ascend a few feet so I can go a little bit more vertical to give my neck a break. In fact, my favorite position for now is an upside-down one where I can maintain my vertical position while still getting close to the reef/bottom for pics - Of course, I do need to rotate my images afterwards, lol. I wonder if photographers have a slightly different take on trim? Eh, probably not - that would be too easy.

If you are executing a task then the best form for that activity can take precedence. Efficient motivation becomes a low priority when you are poking along or maybe working a single scene for a spell.

Conversely as a photographer you don't want to be roto-tilling along stirring things up.

There is good form, alternate form and bad form.

Pete

 

[Cosmographer]

you don't want to be roto-tilling along stirring things up.

Like that guy in the video? I'm sorry for all the bottom dwellers he disturbed, but that's still pretty damn funny - even to a noob like me. A photographer's worst nightmare, lol.

 

[Wolfie]

Nobody has mentioned being a good buddy. a vertical diver will have much difficulty in quickly assisting their buddy!

 

[Divedoggie]

Lynne as it right ... anyone surprised? I'm not.

.

Not surprised, and also quite impressed with her excellent usage of "pernicious."!


I also want to thank you Thal, for my continued enlightenment and education during my internship from afar, as I gleen what information that I can whilst following you around Scubaboard! I took a look at the photos on your profile page the other day and am in awe of the artful masterpiece of a tank carrier in the back of your truck. Particularly impressive is the stylized yoke yoke. In order to not stray too far into this highjack, it looks as though it keeps your tanks in perfect trim during transportation from home to dive site!

 

[Thalassamania]

The kind words are appreciated, but I do wonder where these photos are. What profile page?