What do you mean by "Trim"?

[Walter]

My observations are (and I don't claim to be an expert on DIR) that DIR advocates developing skills. Equipment is a set of tools, but the most important part of the set is to develop skills.

If I'm wrong about this point then there is no contradiction.

When it comes to trim, they seem to want to forget skills and rely totally on equipment.

That seems to be a contradiction to me.

 

[Grajan]

I think it is critical to stress the importance of static trim as opposed to dynamic trim as 'fin trimming' gets a lot of novice divers into bad habits.

Lets assume the general goal is to be able to travel in the horizontal plane (no depth change) with the minimum effort.

If you are trimmed horizontal when not moving your finning effort when you start swimming will all go to forward progress and there will not be any 'side effects'.

If you are leg down when not finning a component of your finning effort will need to lift your legs up when you start to swim. this is not a big efficiency issue but that upward component will also tend to move you vertically so messing up buoyancy.

In extreme cases you will see a diver venting their BC every time they start swimming and then filling it again every time they stop.

More unusually the same problem will inflict the 'head down' diver.

In my experience this lack of static trim is nearly always the reason for divers who cannot stabilize their buoyancy.

Conclusion? Correct trim needs to be determined WITHOUT finning. Input from fins is not trim.

This is precisely why fin pivots are such a dreadful training aid. A well trimmed diver who breaths in should float off the bottom entirely - not just at one end.

This make sense?

 

[MXGratefulDiver]

Grajan once bubbled...
This is precisely why fin pivots are such a dreadful training aid. A well trimmed diver who breaths in should float off the bottom entirely - not just at one end.

Hmmmm ... the OW classes I'm involved with use fin pivots as basically "training wheels" ... a means to introduce the diver to the concept of using their lungs for buoyancy control. After they've mastered the fin pivot, then we move on to neutral buoyancy, where the diver floats off the bottom entirely ... attaining and holding a neutral position without use of hands or feet.

Wouldn't attempting the second skill before mastering the first one increase the risk of the diver going all the way to the surface?

Not to mention that these skills are practiced in the pool very early in the diver's training so that the chances of having good trim are practically nil ... the diver's barely had time to get familiar with their (rental) gear.

... Bob (Grateful Diver)

 

[herman]

Walter once bubbled...
My observations are (and I don't claim to be an expert on DIR) that DIR advocates developing skills. Equipment is a set of tools, but the most important part of the set is to develop skills.

If I'm wrong about this point then there is no contradiction.

When it comes to trim, they seem to want to forget skills and rely totally on equipment.

That seems to be a contradiction to me.

I am not a DIR expert by any strech but having just taken DIR-F I guess I can talk a little on the subject. While the gross adjustment to trim is equipment dependent, as with any dive equipment, we were taught to how to use our body, legs and head mostly to adjust trim as we needed. One of the exercises was hovering horizonal, trimming to head down, back to horizonal, to head up and back to horizonal using just our body. While in class we constantly practiced this skill as well as just hovering at one spot. I found the class to be very skill oriented.

 

[Grajan]

Why does nearly EVERY thread on this board end up being about (or against) DIR?

Nothing against the content of this thread - it just gets boring.

 

[jbd]

that the divers on this board are serious about diving?

I think historically the focus of the many training agencies has been to get people into and out of the water safely. I think they have done an admirable job of this. Techniques wasn't the focus.

The short coming was when divers got more adventuresome and started going into caves and wrecks. In these environments poor techniques gets you into trouble pretty quickly.

Entering from stage left to center stage--the whole DIR concept.

People who are serious about diving want to develope their skills just like the serious amateur golfer or bowler, tennis player etc,etc.

DIR is center stage right now and the diving community is reacting to its presence.

 

[diverbrian]

I know that on a submarine or a boat "trim" tanks are used to adjust the attitude of a boat. In a boat, you are trying to make the boat move straight and level without assistance from the propulsion.

For instance, my stage bottle will make me tend to swim to my left if I am not careful (similar to a plane in a bank turn). This isn't the best for trim but it is where my stage bottle is easiest to reach when I reach deco stops.

I have found that poor weight distribution (when I have it) can be compensated for by adjusting my body position, but it is easier to swim naturally when I have good weight distribution. I have a long way to go before I get to where I want to be, but hopefully I will be doing better at it every dive.

 

[roakey]

A couple of existing discussion about static trim, which is the trim we're talking about when we simply say "Trim."

http://www.scubaboard.com/showthread.php?s=&threadid=4911&highlight=static+trim
About page 4 of: http://www.scubaboard.com/showthread.php?s=&threadid=11998&perpage=15&display=&pagenumber=1
http://www.scubaboard.com/t8232/s.html

Roak

 

[RichLockyer]

Walter once bubbled...
My observations are (and I don't claim to be an expert on DIR) that DIR advocates developing skills. Equipment is a set of tools, but the most important part of the set is to develop skills.

If I'm wrong about this point then there is no contradiction.

When it comes to trim, they seem to want to forget skills and rely totally on equipment.

That seems to be a contradiction to me.

That is incorrect. Your first paragraph, and first paragraph alone is correct.

When the equipment is properly configured, you can use your skills to position yourself as you wish... horizontally, vertically, upside down, etc...

As was said before, you can load 20# of weight along your belly and have "perfect" horizontal trim... but that's all you're going to have.
No amount of "DIR skills" is going to allow you to trim properly if you are wearing 10 pounds of ankle weights.

Yes, equipment is a set of tools, and DIR has standardized on a specific set of tools that has proven to be the most efficient with the fewest compromises.

I don't care of one has logged 20 or 2000 dives... I'm a firm believer that a DIR-F class has something to offer for everyone.
Not everyone leaves the class wanting to continue GUE education, and not everyone will stick with the DIR gear configuration, but I can guarantee that 99% of DIR-F students go home a safer and more aware diver. At the very least, a lot of myths and questions about DIR are answered.

 

[mgri]

so let me see if I got this right. To obtain static horizontal trim you have adjust your weight distribution.

Once static horizontal trim is tuned in. Learn to change your trim through body mechanics.

Sounds easy enough on paper...