Weight distribution

[James79]

Finally, regarding the crotch strap, I did put it over the weight belt at first but was told to put the weight belt on last to assure I can ditch it.

There are 2 schools of thought on this... The one you were advised of is wanting nothing to impede a quick ditching of the weight belt (but allows for accidental ditching of it).
The other (that I personally follow) is under the crotch strap. If it inadvertently gets ditched, the crotch strap can keep you from fully dropping it. For intentional ditching I can pop an end through the crotch strap, or just pop my waist belt letting the crotch strap drop free too.

Respectfully,

James

 

[blueskies_up_ahead]

I see what you're saying and have to admit I see few instances where I would want to drop the weights but it feels unsafe not to be able to. I'd prefer having the weight on my waist strap though. This being said, on my pool test dive when I switched the weight belt to over the crotch strap under water (when told to do so), I forgot to do that not just in the front but also the back. So when I got out of the water the weight belt got caught on the back of the crotch strap. I can safely say that the belt wasn't going anywhere. I had to fiddle quite a bit with it to get it loose. So it's definitely not quick release in any way if it's underneath
Well, all of this isn't really my main issue though. Figuring out steel vs alumimum and weight distribution is the bigger topic and one where I don't really know how to move on, except possibly weight pouches on the front of the waist belt. Anybody have experience with that?

 

[MidOH]

To get the belt off quick you pop the bpw's waist buckle first.

I split my weight between the rig and belt. So that I can take it off at depth, without it flying away, or myself rocketing.

Also all the weight on the rig, makes it heavier to put on. Floaty feet is the best trim problem to have. Its easy to move weight down.

 

[wetb4igetinthewater]

@blueskies_up_ahead

Are you familiar with the concept of a balanced rig? You should only be dumping weight at the surface.

For weight distribution, with a BP/W, you can add a pair trim pockets on both cylinder straps. Some systems allow for putting weight pockets on your waist strap. There are also weight harnesses (like from DUI). Some like them, while others do not. I've moved away from weight belts all together. But it is a personal preference thing.

What issues are you having with weight distribution? Are you foot heavy?

 

[Brett Hatch]

The issue she's having is that she's back-heavy. When in horizontal trim, her center of mass is shallower than her center of buoyancy, which is somewhat stable. But when she rolls a bit to one side, she becomes unbalanced and her rig rolls her over more.

Proposed solutions in the thread were, basically, move as much lead as you can from the back to the belly. If that helped, but didn't quite do the job, then I think swapping negative steel tanks for a buoyant aluminum tank is the next logical step.

Hope this helps.

[edit to correct pronouns]

 

[blueskies_up_ahead]

I split my weight between the rig and belt. So that I can take it off at depth, without it flying away, or myself rocketing.

I didn't mention it, but that's a good point for a weight belt. I guess I might just try to decrease the weight I have on the belt. I guess 2kg would be significantly less straining for the lower back.

@blueskies_up_ahead

Are you familiar with the concept of a balanced rig? You should only be dumping weight at the surface.

I've heard / read about it but when I tried to go into detail the calculation didn't seem to make sense. In theory I don't need weights but that's not my reality. Also steel or aluminum tank isn't always a choice. I take whatever is there.

The issue he's having is that he's back-heavy. When in horizontal trim, his center of mass is shallower than his center of buoyancy, which is somewhat stable. But when he rolls a bit to one side, he becomes unbalanced and his rig rolls him over more.

Proposed solutions in the thread were, basically, move as much lead as you can from the back to the belly. If that helped, but didn't quite do the job, then I think swapping negative steel tanks for a buoyant aluminum tank is the next logical step.

Hope this helps.

He's a she But the rest is correct. But as I said above, I cannot choose the tank. Here in Germany it's usually steel. My next diving is on the canary islands where I believe they use steel tanks as well. My last dive trip was Egypt where they used aluminum tanks. I'll have to deal with whatever is available.

As a side note, I just wanna say that this forum is great! Good advice for a personal issue. People actually try to take the personal situation into account. Elsewhere I found they just tell you what works for them in a totally different situation. Not helpful... So, thanks!

 

[wetb4igetinthewater]

I didn't mention it, but that's a good point for a weight belt. I guess I might just try to decrease the weight I have on the belt. I guess 2kg would be significantly less straining for the lower back.

I see now it is an issue of how to determine your ballast so you avoid turtling.

I've heard / read about it but when I tried to go into detail the calculation didn't seem to make sense. In theory I don't need weights but that's not my reality. Also steel or aluminum tank isn't always a choice. I take whatever is there.

so the idea of a balanced rig is that if your BCD/wing fails, you are still able to swim to the surface. It isn't about calculating, but rather checking, as it depends on the swimming strength of the person. It shouldn't be too strenous either.

He's a she But the rest is correct. But as I said above, I cannot choose the tank. Here in Germany it's usually steel. My next diving is on the canary islands where I believe they use steel tanks as well. My last dive trip was Egypt where they used aluminum tanks. I'll have to deal with whatever is available.

Do you have salt water available to test out weight placement and different ideas with both steel and aluminum cylinders? That would be ideal. Some pictures of your equipment/you diving may help as well.

 

[blueskies_up_ahead]

I see now it is an issue of how to determine your ballast so you avoid turtling.

so the idea of a balanced rig is that if your BCD/wing fails, you are still able to swim to the surface. It isn't about calculating, but rather checking, as it depends on the swimming strength of the person. It shouldn't be too strenous either.

Do you have salt water available to test out weight placement and different ideas with both steel and aluminum cylinders? That would be ideal. Some pictures of your equipment/you diving may help as well.

Well, yes, avoid turteling. The aluminum bp + weight belt worked for that purpose. But now the weight belt caused a back pain. So it's not ideal. I'm starting to think I should try the steel bp again, but with a weight belt and the weight in the front. I would only need 2kg on the weight belt, so that should be better than 4kg. Or I stick with the aluminum bp and add 2kg in trim weight pouches attached to the cam bands. But strangely I needed 6kg of lead with the alu bp (5 would probably do the trick) and only 2kg with the steel bp. So a difference of 3-4kg while the difference in weight between the two backplates is 1,5kg. Anyways, that's just a side note. I'll figure out the exact amount of weight I need.
Regarding balanced rig, a stumbled upon a post that basically calculated the buoyancy, both negative and positive, of all equipement, at surface and at depth in case it varies. It pretty much ended at -7kg at depth in a wetsuit and steel tank and said you could swim up + xkg (don't remember, may have been 5kg), so essentially you're in trouble at depth and be better off using an alu bp to have ditchable weight in case of a BCD failure. That same calculation meant I'd need zero lead with a steel bp which is not true. But maybe this blog post or article or whatever it was is BS.
And finally, no, I have no salt water available. And my next salt water diving will be with steel tanks anyways, so the only thing that will change is that I'll need slightly more weight because of the salt water. The rest, including thickness of my wetsuit, will stay the same. Probably bigger steel tanks though (12l vs 10l). But then again, that's fine tuning. I need this bpw to work in different conditions and can tinker with the amount of weight. But I need to figure out which bp to buy and roughly how to distribute the weight so a) I don't roll over on my back, and b) don't have a back pain from the weight belt. The more we discuss it though, the more I think I have two options: try again the steel bp and put those 2kg on a weight belt on the front of my body to counter balance the rolling. Might be enough... Or second option, stick with the alu bp and distribute some of the weight in weight pouches on the front of the waist band vs the big ones attached to the bp. I feel like the steel bp might be the better option though. Thoughts on this?

 

[inquis]

the only thing that will change is that I'll need slightly more weight because of the salt water.

Ballpark the increase at 2.4% of your total weight on land (incl. gear). This factor is based on average salinity, but somewhere like the very salty Red Sea might need 3%. (An AL80/11 liter or LP85/13 liter steel tank both weigh about 35 lbs if it's helpful.)

 

[Brett Hatch]

He's a she

Sorry about that! I've edited post #35 to correct this.

Well, yes, avoid turteling. The aluminum bp + weight belt worked for that purpose. But now the weight belt caused a back pain. So it's not ideal. I'm starting to think I should try the steel bp again, but with a weight belt and the weight in the front. I would only need 2kg on the weight belt, so that should be better than 4kg. Or I stick with the aluminum bp and add 2kg in trim weight pouches attached to the cam bands. But strangely I needed 6kg of lead with the alu bp (5 would probably do the trick) and only 2kg with the steel bp. So a difference of 3-4kg while the difference in weight between the two backplates is 1,5kg. Anyways, that's just a side note. I'll figure out the exact amount of weight I need.
Regarding balanced rig, a stumbled upon a post that basically calculated the buoyancy, both negative and positive, of all equipement, at surface and at depth in case it varies. It pretty much ended at -7kg at depth in a wetsuit and steel tank and said you could swim up + xkg (don't remember, may have been 5kg), so essentially you're in trouble at depth and be better off using an alu bp to have ditchable weight in case of a BCD failure. That same calculation meant I'd need zero lead with a steel bp which is not true. But maybe this blog post or article or whatever it was is BS.
And finally, no, I have no salt water available. And my next salt water diving will be with steel tanks anyways, so the only thing that will change is that I'll need slightly more weight because of the salt water. The rest, including thickness of my wetsuit, will stay the same. Probably bigger steel tanks though (12l vs 10l). But then again, that's fine tuning. I need this bpw to work in different conditions and can tinker with the amount of weight. But I need to figure out which bp to buy and roughly how to distribute the weight so a) I don't roll over on my back, and b) don't have a back pain from the weight belt. The more we discuss it though, the more I think I have two options: try again the steel bp and put those 2kg on a weight belt on the front of my body to counter balance the rolling. Might be enough... Or second option, stick with the alu bp and distribute some of the weight in weight pouches on the front of the waist band vs the big ones attached to the bp. I feel like the steel bp might be the better option though. Thoughts on this?

I think you're on the right track here. Between these two options, I would personally go with the stainless backplate and less lead. Could be that the aluminum plate with more lead ends up winning out; it's hard to evaluate this sort of thing accurately over the internet. It sounds like your shop has a pool available to try gear out, which is pretty helpful for distribution purposes. Of course the total ballast will be a few kgs different in salt water.

The nice thing is, a plate itself is under 100 euros new, and they really don't go bad. The same plate can be used thousands of times, for decades. So if you go with one and end up wishing you went for the other, you can pick it up cheaply (especially used).