Trim and Weight Distribution

[sffrenchman]

Hi everyone:

I am new to diving with a BP/W rig and I find myself a little head heavy. My BP is a DSS and has weight plates attached to it. I also wear ankle weights and a weight belt. I dive single tank. To correct the trim issue, I was thinking about moving the weights on my weight belt towards my back. I have read people recommending weight pockets attached to lower tank cam strap.

What are the pro and cons of using a weight pocket attached to the lower tank cam strap compare to moving weights toward the back on my weight belt. I like the idea of keeping the weights on the belt since they are still ditchable but wonder whether adding weights to the the lower tank cam strap may be more effective at correcting the problem.

Thanks for your help.

 

[Kern]

Moving weight from your waist to your lower cam strap can only make you more head heavy. It might make more sense to remove the weight plates from the BP & to make up their ballast by adding some to the waist belt & some to the cam bands for better balance.

What sort of exposure suit are you using? What sort of tank do you use? How much ballast do you use in total & how is it distributed?

 

[PfcAJ]

My first thought would be to a) dive more and b) lower the plate or tank. By diving more, you'll be able to control your trim in any direction better, and lowering the plate or tank you'll shift your center of gravity toward your legs a bit.

 

[sffrenchman]

What sort of exposure suit are you using? What sort of tank do you use? How much ballast do you use in total & how is it distributed?

I use a Whites Fusion drysuit with a Whites MK3 undergarment. The tank is a Worthington steel HP 100. My total ballast is 28 lbs: 6 lbs BP, 8 lbs weight plates, 4 lbs ankle weight, 10 lbs on a weight belt.

 

[Kern]

I use a Whites Fusion drysuit with a Whites MK3 undergarment. The tank is a Worthington steel HP 100. My total ballast is 28 lbs: 6 lbs BP, 8 lbs weight plates, 4 lbs ankle weight, 10 lbs on a weight belt.

As you're in a dry suit are you satisfied that there is not too much air getting into your legs/boots.

Make sure the tank is as low as the cam bands will allow.

If still head heavy, remove the weight plate's & start splitting their weight between belt & cam bands until you find the balance.

The posture you assume while diving can also play a significant role in how you trim out.

As PfcAJ has already said, more use can make a big difference. So as you dive the system more, you may find you can move back to your weight plates & even move the weight on your ankles up to your belt.

PS. Are the buoyancy & size specs for a Worthington HP 100 similar to those of a Faber FX 100?

 

[halocline]

The worthington and faber FX are pretty close; I think the worthington is a lb or so more negative.

I suspect the reason you feel head heavy is because you're not used to the 14 lbs on your back. As has been suggested, try moving the tank as low as possible. I don't think you'll find much difference going to cam band weights; those are very similarly located to the weight plates. Once you get the tank right and are used to diving with the extra ballast on your back, if you still are head heavy, you might try removing the weight plate and putting the 8 lbs on your belt. That will make a big difference.

To me I would prioritize getting rid of the ankle weights; those are very inefficient in terms of energy consumption. Do you use positive buoyant fins? Try a pair of negative fins, see if that helps.

 

[Bubbletrubble]

As you're in a dry suit are you satisfied that there is not too much air getting into your legs/boots.

@sffrenchman: Pay attention to this comment by Kern. Do the following test during your next dive...
First, verify that with your current weighting your static trim is still head heavy (in particular, stop kicking and ensure that you aren't dropping your chin down to your chest too much). Then, get vertical to squeeze out more air from your legs and repeat your static trim test. You'll probably find that the amount of air running in your legs can make a difference in static trim. FWIW, you'll get better at managing the bubble in your suit with practice.

Have fun out there...

 

[rongoodman]

Posture has a lot to do with it. If you can keep a slight arch in your back, with your head up and glutes tensed up a little, that might help. It's not all that comfortable at first. I was a little head heavy in the cenotes in double Al80s, but if I kept my butt tight, and my head up against the isolator knob, things worked. Next time I'll add a 3 lb tail weight, which should make life easier.

 

[kanonfodr]

Posture has a really powerful effect on trim, I would try to find someone with a camera and have them take pictures and/or video, especially with you hovering close to a flat, level bottom or training platform. Also, fins can make a huge difference in trim, so if you are using lighter fins you may wish to try heavier fins like the Scubapro Jet Fin, Hollis F1, or similar.

Peace,
Greg