Jim, you need Swimmies for your ankles.
What is Trim?
- Thread starter NCSCUBADOOBA
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Oh, so maybe in my case it is because I wear a 2mm shorty.
Trim has several meanings in the dive world. Of course it refers to your orientation ("balance") in the water column as you remain stationary or move through it.
If you dive dry, it can also mean trimming the excess off your neck and wrist seals so they aren't as tight but are still "water proof."
And then there is the most common use... when the lovely ladies who dive with me turn to one another, giggle and comment on what a lean and trim hunk I am! Well, at least they used to say that years ago.
If you dive dry, it can also mean trimming the excess off your neck and wrist seals so they aren't as tight but are still "water proof."
And then there is the most common use... when the lovely ladies who dive with me turn to one another, giggle and comment on what a lean and trim hunk I am! Well, at least they used to say that years ago.
scubadobadoo
Contributor
Ask Eddie Murphy. Was I too late with that one? Darn!
Storm
Contributor
I've been talking with many folks regarding "trim" and "oreintation" or "attitude".
First off what all of those folk who are helping me with my trim issues have told me is not to relate diving "trim" with any other type of "trim", particulalrly boat or plane etc, as has been suggested here. Both of these other trims are predicated on continuous forward motion where diving trim relates to both while the dvier is in motion and while static within the water column.
Here's a Cole's notes version of what my DI told me.
Think of your attitude (horizontal, vertical and bouyancy) in the water. People will often talk of your center of gravity, but in fact you should be concerned with your center of bouyancy. In terms of the human frame, this is primarily your chest area. It is also compounded buy the floatation in your bouyancy device (BCD/WING).
Positive bouyancy is added to your attitdue when you breathe and thus expand your lungs. This is also compounded by the air in your BC/Wing. Your exposure suit also adds bouyancy mainly to the larger area which is, again, your torso.
In order to be in control of your attitude while at depth you need to counter all that bouyancy caused my your lungs, air in your BC, and the bouyancy in your exposure suit. (Diving 101 here but bear with me). To do this we wear added wieght.
Unfortumnately, most divers are taught to place their weight on a belt that is around their waist.
Think of a teeter totter or balance/scale with the pivot being a few inches forward (above if you're standing) waist. (Where your diaphram is) As the natural boyancy of your lungs lifts your upper body up, the weight on your waist drags your lower body down. The result is that you attitude in the water is not horizontal but rather your body is angled to the horizontal plane. This increases your resistance to current, which flows alling the horizontal plane, and also casues you to ascend slightly when you are moving forward and thus have to work harder to keep yourself down (Remember when you stuck your had out of the window of a moving car. When you keep your hand flat, you cut through the air, when you angle you hand up it raises, etc. The same principles apply to diving. Just look at the OW divers who are constantly adjusting the air in their BCs during a dive. They are dlng this mostly becasue they are out of trim and thus fighting to stay down, and horizontal.
How does one cure this? Simple. Move as much of your weight as you can forward on the horizointal plane so that the weight is directly below where the most of your bouyancy is. This can be acccomplished by simply moving your tank forward in its straps,, adding more weoight below your chest (which is not practical but surprisingly is the basis behind the weight integrated BCD), or more pratically, moving wieght from your belt to your shoulders or upper back area. This is were tank weights come into play. They allow you to move more weight on your back over your chest area thus countering the natural bouyancy of your torso. In some cases weighting your feet or adding bouyancy to your feet may be neccessary to fully "trim out"
For exammple,
0
\
| very poorly trimmed
\
|
__
0___/ properly trimmed
I reailze that the poorly trimmed is a gross exageration, but it's the best I could do with basic line art.
Now here were the difference between boats planes etc. Vessels like these need forward motion to maintain this physical attitude. A diver needs to have the attitude while both in motion, and when idle. The difference being a sailboat that has balasting wieght on it's keel to help keep the boat upright.
This must also be considered for the diver. Imaging a line running down the center of your chest. Addinng too much weight to one side or anotthe will cause you to roll to that side. Hence you not only have to balance yoursel from from your chest to waist but also from your left to right. Once you;ve accomplished these two balancing acts, you've reached the optimum trim for your particular rig.
The final aspect is vertical attidue in the water column. Neutral bouyancy. We've all been taught what neutral bouyancy is so I won't go into that one.
How this all helps us when diving as:
1) it reduces our drag while in motion, thus we work less and burn less air.
2) it keeps your fins out off the bottom thus reducing silting
3) it increase our efficency in minor depth control by allowing us to usethe air in our lungs to asscend and decend sliightly during our dive, thud we work our major muscles less, thus we use less air.
Anyway that what I was taught...Just my 2 cents.
First off what all of those folk who are helping me with my trim issues have told me is not to relate diving "trim" with any other type of "trim", particulalrly boat or plane etc, as has been suggested here. Both of these other trims are predicated on continuous forward motion where diving trim relates to both while the dvier is in motion and while static within the water column.
Here's a Cole's notes version of what my DI told me.
Think of your attitude (horizontal, vertical and bouyancy) in the water. People will often talk of your center of gravity, but in fact you should be concerned with your center of bouyancy. In terms of the human frame, this is primarily your chest area. It is also compounded buy the floatation in your bouyancy device (BCD/WING).
Positive bouyancy is added to your attitdue when you breathe and thus expand your lungs. This is also compounded by the air in your BC/Wing. Your exposure suit also adds bouyancy mainly to the larger area which is, again, your torso.
In order to be in control of your attitude while at depth you need to counter all that bouyancy caused my your lungs, air in your BC, and the bouyancy in your exposure suit. (Diving 101 here but bear with me). To do this we wear added wieght.
Unfortumnately, most divers are taught to place their weight on a belt that is around their waist.
Think of a teeter totter or balance/scale with the pivot being a few inches forward (above if you're standing) waist. (Where your diaphram is) As the natural boyancy of your lungs lifts your upper body up, the weight on your waist drags your lower body down. The result is that you attitude in the water is not horizontal but rather your body is angled to the horizontal plane. This increases your resistance to current, which flows alling the horizontal plane, and also casues you to ascend slightly when you are moving forward and thus have to work harder to keep yourself down (Remember when you stuck your had out of the window of a moving car. When you keep your hand flat, you cut through the air, when you angle you hand up it raises, etc. The same principles apply to diving. Just look at the OW divers who are constantly adjusting the air in their BCs during a dive. They are dlng this mostly becasue they are out of trim and thus fighting to stay down, and horizontal.
How does one cure this? Simple. Move as much of your weight as you can forward on the horizointal plane so that the weight is directly below where the most of your bouyancy is. This can be acccomplished by simply moving your tank forward in its straps,, adding more weoight below your chest (which is not practical but surprisingly is the basis behind the weight integrated BCD), or more pratically, moving wieght from your belt to your shoulders or upper back area. This is were tank weights come into play. They allow you to move more weight on your back over your chest area thus countering the natural bouyancy of your torso. In some cases weighting your feet or adding bouyancy to your feet may be neccessary to fully "trim out"
For exammple,
0
\
| very poorly trimmed
\
|
__
0___/ properly trimmed
I reailze that the poorly trimmed is a gross exageration, but it's the best I could do with basic line art.
Now here were the difference between boats planes etc. Vessels like these need forward motion to maintain this physical attitude. A diver needs to have the attitude while both in motion, and when idle. The difference being a sailboat that has balasting wieght on it's keel to help keep the boat upright.
This must also be considered for the diver. Imaging a line running down the center of your chest. Addinng too much weight to one side or anotthe will cause you to roll to that side. Hence you not only have to balance yoursel from from your chest to waist but also from your left to right. Once you;ve accomplished these two balancing acts, you've reached the optimum trim for your particular rig.
The final aspect is vertical attidue in the water column. Neutral bouyancy. We've all been taught what neutral bouyancy is so I won't go into that one.
How this all helps us when diving as:
1) it reduces our drag while in motion, thus we work less and burn less air.
2) it keeps your fins out off the bottom thus reducing silting
3) it increase our efficency in minor depth control by allowing us to usethe air in our lungs to asscend and decend sliightly during our dive, thud we work our major muscles less, thus we use less air.
Anyway that what I was taught...Just my 2 cents.
IwakuniDiver
Contributor
Lately I have been noticing that I have been having a tendancy to be "feet up". I have a weight-integrated BC with trim pockets behind my shoulders. I had been passing this off as being bouyant on my feet but could I be heavy on the trim pockets instead?
I'm not getting a real radical rotation, it's only enough to be a little annoying when I stop and sit there for a while.
BTW, my fins are negatively bouyant and my feet still are seeming to float.
I'm not getting a real radical rotation, it's only enough to be a little annoying when I stop and sit there for a while.
BTW, my fins are negatively bouyant and my feet still are seeming to float.
OP
NCSCUBADOOBA
Contributor
W-O-W!
Who knew TRIM had so much controversy LOL....
BTW, my boyfriend made the same remark , Mike...
Eddie Murphy? LMAO...
Maybe I'm lucky, I can keep my buoyancy in check and stay flat/horizontal in the water. But... I do have OTHER issues ......hmmmm. ha ha
Angela
Who knew TRIM had so much controversy LOL....
BTW, my boyfriend made the same remark , Mike...
Eddie Murphy? LMAO...
Maybe I'm lucky, I can keep my buoyancy in check and stay flat/horizontal in the water. But... I do have OTHER issues ......hmmmm. ha ha
Angela
MoonWrasse
Contributor
NCSCUBADOOBA:
You can always look it up in the Urban dictionary, of course, and your BF will be proven correct
http://www.urbandictionary.com/
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