BP/W Weight question

[gkrane]

I am looking into starting a GUE Fundies class and will be transitoning to a BP/W configuration. I have done an extensive amount of reading but do have a question. What does everyone do for weighting with a DIR BP/W rig? I see posts where some backplates allow bolt on weights like DSS but this does not neem advisable for travel or if you need to dump weight in an emergency. How about weight pouches and how would they work with a DIR BP/W rig?

 

[VR78]

That's exactly the question I asked my Fundies instructor. His response? "Why do you think you'll need any weights at all?'. And sure enough, nobody in the class did.

 

[rivers]

I am looking into starting a GUE Fundies class and will be transitoning to a BP/W configuration. I have done an extensive amount of reading but do have a question. What does everyone do for weighting with a DIR BP/W rig? I see posts where some backplates allow bolt on weights like DSS but this does not neem advisable for travel or if you need to dump weight in an emergency. How about weight pouches and how would they work with a DIR BP/W rig?

it depends. In warm water, I don't need any weight. In the UK, I need 2kgs for fresh water in my twinset, which is v-weight and sits between my cylinders. In the sea, I use a 2kg weight belt. Most people I know use a standard weight belt. If I'm diving a single, i use a combination of weight belt and a bit of weight on the cam bands

 

[gkrane]

That's exactly the question I asked my Fundies instructor. His response? "Why do you think you'll need any weights at all?'. And sure enough, nobody in the class did.

Now i'm just confused. I understand a SS backplate removes about 6 lbs but I need more than that.

 

[RJP]

Now i'm just confused. I understand a SS backplate removes about 6 lbs but I need more than that.

The ultimate answer to where to put weight on a BP/W rig is 'it depends'

1.) It depends on HOW MUCH weight you need.
2.) It depends on where that weight is best placed from TRIM perspective.
3.) It depends on how much weight needs to be DITCHABLE

STEP 1: HOW MUCH WEIGHT

While it's true that you might need more than 6lbs currently, it's important to note that your current BCD is most likely positively buoyant itself. As much as 4lbs or more, depending on the model. So a switch to a BP/W rig that is ~6lbs negatively buoyant means a 10lb swing in how much lead you need to add.

Another factor that helps determine how much weight you'll need as you "transition to a BP/W rig" is whether you're transitioning tanks as well. Are we talking a single tank or doubles? And what kind of tanks? With a single AL80 you'll probably need some extra weight. With a set of steel doubles... maybe not.

STEP 2: WHERE TO PUT THE WEIGHT

Once you know how much weight you need, you need to figure out where to put it, starting with the impact on your trim. One of the benefits of a BP is that it puts the weight where the buoyancy is - where the wing and your lungs are located. This often helps improve people's trim significantly. Adding more weight from there should be done with an eye towards further refining - or at least not hurting - your trim.

For purposes of keeping discussion focused on "weight" let's assume you won't change anything else for now, let'd further assume that your trim is perfect with your new BP/W rig... but you need to add weight. Let's say 12lbs of lead, as an example

Well, you could put all of it on a weight belt, but that will move your center of buoyancy towards your feet and put you in a head-up situation. To help improve that, you could add a 6lb weighted tank adapter or bolt-on weights to your BP and 6lbs on a weight belt. This would help keep you in trim better as it would spread the weight out "north and south" if you will. Another option is to add weight pouches to your cam bands. The nice thing about that approach is you can move the weight to top or bottom cam strap, depending on where you need it for trim purposes.

STEP 3: HOW MUCH WEIGHT IS DITCHABLE

Just because you need to add weight doesn't mean that ALL of it needs to be ditchable. In the 12lb example above, having six lbs of ditchable weight should be more than sufficient in most cases... assuming you're properly weighted overall and diving a balanced rig.

Options for accomodating ditchable weight include:
- traditional weight belt
- weight harness such as DUI
- add-on weight pockets

DUI weight harness:

Add-on weight pouches are available from Halcyon, Dive-Rite, Hollis, and other manufacturers...

 

[gkrane]

I have had really great experience with Hollis gear but $160 for the weight pouches is nuts. Will look at the dive rites.

 

[Lorenzoid]

One of the principles we discussed and worked on in Fundies was how to weight ourselves. One of the exercises we did on the first in-water day of Fundies was to test whether the weighting we had discussed in class really worked for each of us in the water to achieve the so-called "balanced rig." We did two tests in shallow water. First, with a full tank, the instructor had me descend to the bottom at something like 30 feet, dump all the air from my wing to simulate a total failure of the wing, and then see if I could swim up to the surface. The ability to "swim it up" if you have a total wing failure is one half of the balanced rig equation. If you can't swim it up, then you have too much non-ditchable weight, and you may need to make some of it ditchable. In fresh water, with a 5 mm wetsuit, steel backplate and aluminum 80 tank, and with 6 lbs. of lead in trim pockets on the upper cambands, I had no difficulty swimming it up. Next, with a nearly empty tank the instructor had me see if I could hover at safety stop depth. Unless you have enough weight, then even with the wing as empty as possible you will tend to float up. The ability to hold a safety stop is the other half of the balanced rig equation. Whatever your weighting, you also need to ensure the weight is distributed over your body in a way that you can comfortably swim "in trim," that is, horizontally, and not tipping forward or backward. As mentioned by others, weight pouches can help with that. But whether you need weight pouches and how much weight you will need are all things that will be discussed in class. Bring a couple of pouches.

 

[gkrane]

One of the principles we discussed and worked on in Fundies was how to weight ourselves. One of the exercises we did on the first in-water day of Fundies was to test whether the weighting we had discussed in class really worked for each of us in the water to achieve the so-called "balanced rig." We did two tests in shallow water. First, with a full tank, the instructor had me descend to the bottom at something like 30 feet, dump all the air from my wing to simulate a total failure of the wing, and then see if I could swim up to the surface. The ability to "swim it up" if you have a total wing failure is one half of the balanced rig equation. If you can't swim it up, then you have too much non-ditchable weight, and you may need to make some of it ditchable. In fresh water, with a 5 mm wetsuit, steel backplate and aluminum 80 tank, and with 6 lbs. of lead in trim pockets on the upper cambands, I had no difficulty swimming it up. Next, with a nearly empty tank the instructor had me see if I could hover at safety stop depth. Unless you have enough weight, then even with the wing as empty as possible you will tend to float up. The ability to hold a safety stop is the other half of the balanced rig equation. Whatever your weighting, you also need to ensure the weight is distributed over your body in a way that you can comfortably swim "in trim," that is, horizontally, and not tipping forward or backward. As mentioned by others, weight pouches can help with that. But whether you need weight pouches and how much weight you will need are all things that will be discussed in class. Bring a couple of pouches.

This makes sense. I guess I am overly excited and jumping the gun a bit since I don't even have class scheduled yet. Will continue to read and learn.

 

[elgoog]

RJP and Lorenzoid covered a lot of important points about weighting and the balanced rig, so I'll try not to repeat. I'm also answering your questions out of order but hopefully it makes sense. My wife and I have DSS steel plates with the weight plates, so the information below is based on that.

How about weight pouches and how would they work with a DIR BP/W rig?

These pouches worked great for us and are a lot cheaper than the ones with buckles and other quick release devices (which I don't think you really need) - XS Scuba Single Weight Pocket
You can move them around on your rig (waist strap, cam bands) or put them on a weight belt during your Fundies class to get your weighting dialed in. In our Fundies 1 class, we started with the weight plates off and used the pockets to figure out how much we needed and where. It turned out that both of us had enough weight on the cambands to justify using the weight plates.
These pockets are also what we use when we're traveling and we have 4 each to split between weight belts and cam bands.

I see posts where some backplates allow bolt on weights like DSS

this does not neem advisable for travel

For air travel, we take 2 of the pockets mentioned above in lieu of the bolt on plates and put them on our cam bands. It's not as nice as having the plates but the effect on trim is almost the same.

if you need to dump weight in an emergency.

As already mentioned, you don't need to dump all your weight in an emergency. If your total weighting is less than or really close to what the weight plate provides then they might not be the right way to go.

The weight plates are really nice to have IF you need that much weight AND you need that weight around chest level.
Example - In fresh water, having weight plates on makes my wife go feet up as she has less weight on her weight belt to act as a counter balance and trim her out properly. So, we remove the weight plates and put 4lb in her camband pockets. In saltwater, the amount of weight on her weight belt is higher and works really well with the plates bolted on.

Assuming you go with DSS, my recommendation would be to not buy the weight plates when you buy your rig. Do Fundies and figure out the weighting first. Along the lines of what VR78 said, you will most likely end up needing less than you think and the weight plates might not be the right solution for you.
Also note that the weight plates only work with the DSS steel plate. I'm not familiar with the water temps in AZ or what kind of wetsuit/drysuit you use but I think a steel plate will be the right choice for you, regardless.

 

[VR78]

...you will most likely end up needing less than you think...

Yep, that. Most likely less and quite possibly much less )