Just got a Back Inflate

Hey,

Hey guys I just transitioned from a jacket BC to a back inflate BC and it is a ScubaPro Knighthawk, I heard they are pretty good. I have had two times to try it out and I am loving it so far. I just need a few tips..

At the springs I felt as if I was pretty horizontal and my trim was pretty good but I was probably way to excited on trying out my BC than paying attention on how well i'm using it.

The next day I got a tank and hopped in the pool to do some more buoancy training and see if I was able to stay keep horizontal trim because i'm always looking to get the best air consumption. I was not wearing a suit just fins, booties, regs, tank, mask, and BC. I have ScubaPro Jet Fins which are pretty heavy and might be causing the problem i'm about to state. I noticed how I can only keep horizontal trim when I am moving but if I try to stay still my feet sink and my body tries to go up in a vertical position and i'm guessing this is called feet heavy. I was wearing 12lb's at the time (1x3lb in each bottom front pocket and 1x3lb in each back middle pocket equaling a total of 12lbs.) Keep in mind I am not wearing my 5mm suit which makes me buoyant a lot. Another thing is I hope I am strapping my tank on correct as in height, I was taught in training that with a single strap BC you strap the tank where the 1st stage is about right behind the bottom of your neck and the strap goes around near the top of the tank not very middle ( I think it looks kinda rediculous lol ) I tried putting my hands out in front of me and bending my legs in a 90 degree angle and frog kick but I still tend to go vertical when trying to stay still. My posture seemed pretty correct, chest out and head up so I wasn't sloppy or anything, I want to be able to get perfectly straight to where I can just float along, nothings perfect but practice does help just wondering what are some good tips.

Thanks,

Jake

RE the height - Make sure the tank doesn't hit you in the back of the head. The "bottom of your neck" thing may depend on the length of one's neck. People with longer necks can put their tanks higher then people with no necks.

Some people remove weight from their belt line and move it up to the tank strap with the use of a pouch.

pafindr:

RE the height - Make sure the tank doesn't hit you in the back of the head. The "bottom of your neck" thing may depend on the length of one's neck. People with longer necks can put their tanks higher then people with no necks.

Some people remove weight from their belt line and move it up to the tank strap with the use of a pouch.

Click to expand...

With my Suit in Freshwater I require about 18lbs. If I put 2x 3lbs in each of my middle back pockets near my tank strap and 1x 3lbs in each of my front bottom pockets near my waistline will that help better?

Thanks,

Jake

If you naturally end up in a head-up/feet-down position when not moving, you need to change your weight distribution. There's a good chance that shifting ballast from your hips toward your head will help improve your trim issue. There are lots of ways to do this. Most people end up shifting some lead from the weight-integrated pockets (at the hips) to trim weight pockets (at the level of your shoulder blades). Placing a small weight around the neck of the tank or switching to more positively buoyant fins are also options.

The "correct" height for tank positioning on a BCD meets the following requirements:

• Is "comfortable" for the diver,
• Attaches the tank securely,
• Promotes proper static horizontal trim, and
• Doesn't cause the first stage to smack into the back of the diver's head (might be difficult to do with certain first stages).

Some people would add another requirement -- that the diver can reach/operate the tank valve.
It's certainly true that tank positioning on the BCD can affect trim. Moving the tank up on the BCD can improve head-up/feet-down trim, but there are limits to how far one can move the tank. The physical dimensions of the tank can also be a factor. For example, I know that I have a more difficult time getting trimmed out with a stubby HP80 tank. YMMV.

The BCD strap is there to help the user pick up the rig and judge whether the tank is where it needs to be. That's why some manufacturers call it a "tank positioning strap."

When you change your gear configuration, you need to go back to square one with regard to making sure you have enough ballast (weight check) and that the ballast is distributed properly (weight positioning). At least in terms of weighting and trim, that's why practicing without a wetsuit and less weight in a pool won't translate readily to wearing a 5mm wetsuit and more weight in the ocean.

The Knighthawk is a well-built BCD. My buddy has put 900+ dives on his. He's also been very happy with Scubapro customer service.

Enjoy the BC...

You will have to play with it and see what works best.
Just remember not to put to much weight in pockets that you can not ditch. If you have to much weight that you can't ditch you run the risk of not being able to get to the surface in an emergency.

There's no magic bullet that works in all environments . . . each time you change exposure protection and water conditions, you will have to rework your weight and balance. My guess is that, in your 5 mil wetsuit, you have enough buoyancy on your legs to counteract the heavy fins. In the pool, you did not.

I can dive Jets or other heavy fins in cold water with my dry suit (or in warm water with the dry suit, to think about it) but when I work with student in the pool, I can't use them, or I'll tend to tilt feet-down. This would be my guess -- the lack of exposure protection just made your balancing strategy not work in the pool.

Thanks for the tips guys, I will defiantly try moving weight around and see what the result is. Also, is there a product where I can use a D Ring to hook weights too? That would be cool because I got a couple D rings on my shoulder straps at the top.

Jakestg:

Also, is there a product where I can use a D Ring to hook weights too? That would be cool because I got a couple D rings on my shoulder straps at the top.

Click to expand...

If you have access to them, ankle weights clip onto D-rings quite nicely and they usually come in small denominations of weight.

You can also tie a bolt-snap to a lead weight (containing slots for a weightbelt) with bungee cord.

Bubbletrubble:

If you have access to them, ankle weights clip onto D-rings quite nicely and they usually come in small denominations of weight.

You can also tie a bolt-snap to a lead weight with bungee cord.

Click to expand...

Can you get a picture of this? I saw someone mention this but I would like a picture to better understand.

Jakestg:

Can you get a picture of this? I saw someone mention this but I would like a picture to better understand.

Click to expand...

If you're asking about tying a bolt-snap to a lead weight with bungee cord...

In my previous post, I included weblinks to the bolt-snap and bungee cord on the Dive Gear Express website. The links should give you a good idea of what a bolt-snap is and what I mean by bungee cord.
The lead weight that I was referring to has webbing slots and looks like the ones on this Sea Pearls webpage.

I don't have any examples handy. Thread the bungee cord through the weight slots, pass the cord through the eye of the bolt-snap, and tie it off. It doesn't have to be pretty. Just make sure that the attachment is reinforced by a few wraps of the bungee cord.