Let's Talk About BCs (part 2)

See I told you I was going to be better about getting the tips up on time! Okay let's see this week we are going to talk about the second most important reason that you wear a BC: Surface Floatation.

As scuba divers we try not to spend too much time at the surface. After all you paid all that money to go underwater right? Unfortunately we have to come to the surface every once in awhile. We may need to talk to our buddy, check our navigation skills or even just rest a little while. All of these things require not only a stop at the surface but the ability to be able to comfortably sit there while we accomplish our task.

So with all that being said let's discuss the techniques involved with doing that.

First of all, our main goal is to be in complete control and to be as relaxed as we possibly can. Sometimes that is easier said then done when you are out in a little bit of rough water. Nobody likes to be drinking ocean water right? So we want to make sure we can easily get our heads up out of the ocean. We all learned in our open water scuba class that when you come to the surface you should fill up your BC so that you can stay afloat. No big deal. Well it can be a big deal if you are over weighted. We not only want to be able to stay head-above the water we don't want to have to fill our BCs so much that it feels like it is crushing our ribs.

The key to this is proper weighting. If you wear the correct amount of weight then your BC can easily lift you out of the water up to almost your waist! Weighting however is only one piece of the puzzle. The second piece is the type of BC that you are using.

BCs come in many shapes and sizes and all of them have different gizmos attached to them but when you break them down to their simplest state there really are just two types: Back buoyancy and Front buoyancy.

Back Buoyancy

Back buoyancy BCs are the type of BCs that most people wear. This BC will fill with air in the back upon inflation. Most people use this BC because they feel less restricted while it is inflated. Below is a picture of a back buoyancy BC.

While these BCs appear to be more comfortable, they actually are not. If you are properly weighted (i.e. not over weighted) you should have no problem staying a float at the surface without filling your BC all the way up.  The other issue, which is far more dangerous, is your position in the water. When you inflate a back buoyancy BC all the air will rise to the top of the vest. That happens on all BCs but the problem is when the vest is full then the air in the vest will rise and push you forward which will keep you face down in the water. Doesn't this defeat the purpose of having a BC? When I float I want to have my head out of the water not in it.

I have spoken with numerous instructors on this subject and they assure me that you can dive safely with a back buoyancy BC. All you need to do is add some weight to the back of the vest and balance out the BC. Trust me, you can't add enough weight to even things out and once you do you are far too over weighted to dive. Besides is adding unnecessary weight to yourself when you dive a good thing?

Front Buoyancy

Front buoyancy BCs are the less popular style of BC. This BC will fill with air primarily in the front upon inflation. Below is a picture of a front buoyancy BC.

While these BCs are less popular they are much safer. If you compare the two pictures you will easily see the difference in where the vest retains most of its air. In the front buoyancy BC the air stays primarily in the front and on the sides. Just like with the back buoyancy BC the air in the front buoyancy BC will rise to the top. The nice thing about the front buoyancy BC is that when the air rises to the top it will actually push us over on our backs completely raising our heads out of the water.

The other helpful thing is that this vest will float us easily on our backs and get our lungs out of the water. As long as our lungs are under a little water pressure it will be more difficult to breathe then if they are under standard atmospheric pressure.

Summary

Well folks I think it is easy to see which side of the fence I am on but I always do my best to remain objective and present you with the facts. Let me add a few more, I dive with a lot of people and I have seen a tremendous amount of different gear configurations. I subscribe to the theory of "Less Is More". When people are uncomfortable in the water and especially at the surface their panic level increases and they no longer think rationally. I say this because I see it everyday. When you make someone comfortable they have a lot more fun. Remember, we all have to come to the surface at the end of our dive...isn't it a lot easier if you know that when you get there tired and maybe a little chilly all you have to do is add a little air to your BC and you will float face out of the water safely and comfortably?

Until next week, stay wet, stay warm and stay face out of the water on the surface!

Return to Diving Tip List.