Buoyancy Propulsion and Trim

[The Chairman]

Robert Arak aka ScubaTude here on ScubaBoard might be the closest of the three Elena mentioned to you. Any of the three would be great, so just send them a PM and ask.

 

[VR78]

was in Cali

Andrew Georgitsis is...

 

[glock34girl]

People typically finish an OW course with too much weight for a variety of reasons (breathing, finning, etc). So if you haven't adjusted this you probably have too much weight. Having trouble with a safety stop is often because someone needs to keep air in their BC because they are too heavy, and even a minor rise in depth when you are shallow results in all the air in your BC expanding, and up you go.

Once you get weight right trim is largely figuring out how to distribute the weight so it tends to keep you horizontal vs vertical.

Both weighting and trim are a lot faster to fix with a skilled instructor or mentor helping.

Oh, and kicking with your knees rather then your hips is another flutter kick technique. It works well once you get weighting and trim right.

When I started my certification I needed 36lbs plus ankle weights. I am now without ankle weights and 26lbs. Cold water diving with a 7mm suit. I feel like if i take any breath at a safety stop I torpedo to the top. But at depth I feel like I'm constantly kicking in order not to keep descending. I am obese and have been working out in an effort to be a more efficient diver and just over all more healthy. Not sure if this is contributing to the problem. I see some of my chunky friends with great buoyancy skills.

---------- Post added July 20th, 2015 at 09:02 PM ----------

great post, good questions

glock34girl ... it sometimes helps if you think back to a teeter totter / see saw ... once you have the correct amount of weight, removing wight from one end, and putting it on the other will tilt you in the water ... that's the basic premise ... usually only a small change is needed to get you in trim (I hope I didn't just make worse your understanding with my try to help you)

I have two five pounders in my trim pockets. Should I perhaps put my 2 Twos and my 2 Ones from the integrated pouches in the trim pouches and the five pounders in the pouches?

---------- Post added July 20th, 2015 at 09:04 PM ----------

Too funny at the "insane" comment. I think the word is "snobbish". The nickname came from thez_yo, a UTD diver, who said her buddy, aeweems had "snobbish amounts of trim" when she finished Netdoc ' s class.

Glock34girl, come on down to the Keys.

There are some good instructors on the west coast that could work with you and provide some mentoring. These are the ones who come to mind:
Robert Arak of ScubaTude
Peter Guy & TS&M (Lynne)
NWGratefulDiver (Bob)


\\


Sent from my SM-G900V using Tapatalk

Id like to visit the keys one day, indeed! Out of my budget after buying all my gear and taking classes. lol have to wait a bit but I will look into those names you sent. Thanks!

---------- Post added July 20th, 2015 at 09:06 PM ----------

Where bin California. I h underwave some friends in SoCal that might be able to help. One is an instructor and a cave diver. He has his s*** together underwater.

I am in central california so it's a drive no matter where the person is. lol

 

[KevinNM]

I have two five pounders in my trim pockets. Should I perhaps put my 2 Twos and my 2 Ones from the integrated pouches in the trim pouches and the five pounders in the pouches?

Maybe, but without seeing you in the water it would all be guesswork for me. I think getting the weighting right first is essential. You can just hold them in a mesh bag while testing, you don't have to keep fiddling with weight belts or weight pouches. The total weight you are using seems pretty high to me, but I could be wrong too. I'd suggest redoing the weight check in a pool just like you were shown in you OW class, but relaxed so you don't fin or kick, and then fully exhale. Also ensure your BC is completely empty of air.

But also consider doing a peak performance buoyancy class if there is an instructor near you who (in the water) looks like the diver you want to be.

 

[boulderjohn]

I have about 40 dives and each one gets more and more frustrating for me. I seem to be able to stay somewhat where I want to be if I am moving but stop to look at something and I am usually plummeting to suck on an urchin. I have noticed that I am more probably at a 45 degree angel than horizontal. I have been terribly frustrated because one dive seems okay and then the next dive I am surfacing faster than Id like. Sometimes when I am at depth I feel like I have too much weight but then when I am a bit shallower around 15-18 feet i have to be very careful not to take a full breath or its a rocket ride to the top.

First, diving in a 7mm suit is very frustrating because you have to be overweighted during part of the dive. You need a certain amount of wieght to sink, and when the suit compresses as you descend, you don't need it any more.

Next, rocketing to the surface when you are in shallow water can actually be a sign that you are overweighted, which is the opposite of what common sense tells you. If you were perfectly weighted, you would have close to no air in your BCD. In that situation, you will control your buoyancy easily simply by changing the amount of air you hold in your lungs as you breathe. It's pretty easy. That changes when you are overweighted. Every pound of unnecessary weight requires nearly the volume of a pint of air for buouyancy. If you are 12 pounds overweighted, that requires the volume of 6.5 gallons of air in your BCD in order to be neutrally buoyant. That air will expand and contract as you ascend and descend, and the closer you are to the surface, the more it will expand and contract. When you are shallow, your 7mm wet suit is also expanding and contracting significantly. All of this is too much for your lungs to overcome, and you will take that rocket ride to the surface. So when you are diving and finishing your dive, check to see how much air is in your BCD. There should be very little there during a safety stop.

Last summer I conducted the OW checkout dives for some students I had not had for the pool work, and they were in 7mm wet suits. One of them had intentionally done his pool work in a 7mm suit so that he would now what his weighting needs would be. He told me he needed 22 pounds. I looked at him and thought, "No way." By the last dive, I had him down to 10 pounds. We distributed it so that he could easily get proper trim. At the end of the dive he was excited about how much easier the diving was with the right amount of weight and with good trim.

So why did he think he needed 22 pounds after his pool experience? It was because he had a pool instructor who still taught his classes in the old school technique of having the student demonstrate skills while kneeling on the bottom of the pool. For students to do that comfortably, they have to be overweighted, especially in a thick wet suit. A couple of years ago I had to pose for some pictures showing the difference between teaching students while they are in horizontal trim and while they are on their knees. I had not done a skill on my knees in years, and I was shocked by the experience. I could not do the skills on the knees with my normal weighting. I had to wear at least double my normal weight in order to do the skills comfortably in that position.

 

[Yellowdog]

I was in Key Largo a couple of months ago to get my 16 year old son ow certified. We were going to do it with Netdoc and I was going to tag along and do the buoyancy, propulsion and trim at the same time as apparently it is close to his ow class. Unfortunately for my son and me, Pete had to change his schedule at the last minute and my son ended up taking his ow with one of the big dive outfits in Key Largo. The instructor was a smart guy and took the instruction seriously. My son got plenty of individual attention with only 2 students in the class, and did learn the basic dive skills well, but the entire class was taught on the bottom of the pool, the bottom of the ocean or hanging on a drop line. There was almost no attention to buoyancy. After my son got his ow card we went on several boat dives while we were still in Key Largo. I immediately realized that although he knew how to put together his gear, read his gauges and clear his mask, he really had not been taught anything about buoyancy, propulsion and trim. He looked more like a drunk monkey swinging through tree tops than a diver observing a reef. Not only had his instructor not practiced these skills, he had not really mentioned these skills. His instructor also had started him with 8lbs of lead and he was well over weighted at 6'1",150lbs, no body fat and trunks. I was able to get him in a little better trim by working with him myself, losing 2lbs and by watching some proper trim and buoyancy videos on you-tube in the hotel. Since then we have taken the UTD - B P & T course together ( it turns out he is actually negatively buoyant in fresh water ) and he is starting to get the basics. It is such a shame that most divers are not taught proper buoyancy right form the start. It would make the learning curve so much shorter, and diving so much more enjoyable.

 

[wetb4igetinthewater]

For those in the Puget Sound area, I'd recommend Bob Bailey (nwgratefuldiver) for this. I took a UW photography class, and those 3 things are what we focused on at first. It really helped me as Bob broke some of my bad habits.