Criticize or comment on my BPW/W weighting

[jzipfel]

I have been playing around with the placement of my weights and as I picked up a weight belt I got into a discussion with the shop owner about my weight placement; it got me to thinking that I need more opinions. So here goes....

currently I have a Hog BP/W, 32 lb lift. So my total weight is 6 lb plate, then threaded directly to the BP/W waist band ar two 2 lb bullets against the back, then one XS scuba dump able pocket with a 4 lb hard weight, then threaded directly onto the waist belt is a 4 lb weight. Same configure on right and left side. This is the config when diving my drysu it in Puget Sound. When in Hawaii, only the two pockets switch 3 lb weights are used. This gives me a total of 26 lbs ( not counting any misc. items) of weight when dry and 12 lbs when in warm water.

im pretty sure the weight is spot on as all weight checks and objective actions such dropping at beginning of dive, holding a se and ability to swim it all up with an empty bladder at the end of a dive are all good. whew! Now to the question....

how ow should I config these weights. I will tell you I have tried to place some weight on the tank bands and it was no good. Very top heavy so I abandonded that.

my objective is two fold, ability to dump weight at depth if needed and ability to dump weight on surface so I can float in an emergency, all must be easy, straightforward and safe.

FIRST: my current config I think allows quick, easy and safe dumping of weight at depth. I can dump 4 or 8 lbs quickly and easily. I did not want to dump more than that at depth so as not to rocket up but can do so controlled. However this may not allow me to dump enough if on the surface if needed. I could undo the BP/W waist belt and dump anothe 4 lbs if needed.

OPTION TWO: keep weight pockets on BP/W waist belt. Then under this put a separate waist belt with others weights. This would give me ability to dump 4 or 8 then is it hits the fan, unbuckle other belt and drop another 12 lbs in one shot. This would require undoing the BP/W belt first. Not very intuitive.

OPTION THREE: get bigger pockets on each side, place 10 lbs of weight in each. This would allow me to dump 10 or 20 lbs quickly in any situation. I seem to have a prejudice against this since I think dumping 40 % of my weight at depth could be bad news as I could go up too fast, but would be good on the surface if needed.

if you have made it this far in my post, thank you. So these are my struggles and would love to hear others suggestions about my options or other options I have not considered. I think the issue is primarily when diving dry since all of my goals are met when diving in warm waters.

thanks in advance for any help you could provide.

 

[Mr Carcharodon]

Why would you want to drop more weight than is needed to get neutrally buoyant? Is there a situation where you would want to drop 20 pounds of weight? An other thing to think about is what concentrating all your weight in one place does to your trim. That might work for a few people but not most.

 

[ronscuba]

The large weight pockets you are considering, do they let you easily pull out individual weights for dumping ? If not, how about putting 2 small XS weight pockets next to each other on each hip ? Each one holds 4-5 pounds letting you dump in 4-5 pound increments.

 

[TSandM]

I can only think of two situations where you might want to drop weight. One is a dry suit flood with a failed wing (and we don't normally plan for two major failures), and the other is an emergency where you want to be irretrievably positive on the surface. Assuming that you are out of gas, and therefore unable to power inflate your wing, and that your mental status doesn't permit oral inflation, you need only drop enough weight to be positive. Since, correctly weighted, you start the dive negative only by the weight of the air you intend to breathe, you need only drop that much weight, or a bit more. Unless you are using 130s or doubles, the 8 pounds you have easily ditchable will do it.

 

[tbone1004]

ok, so. Going to ignore everything you wrote up there other than "Hog 32lb rig", 26lbs needed in cold, 12lbs needed in warm. All ditchable comments are based on the theory of ditchable weight. I don't dive with ditchable weight because I almost never carry any, and don't really see the benefit in ditching any more weight than the weight of gas in a full cylinder. I also believe that anyone diving a rig they can't keep at the surface with an empty rig shouldn't be diving that rig, so keep that in mind.

Addressing the ditchable weight first. You want to be able to ditch the total weight of air in the tank, not much more in a wetsuit. Remember that you are neutral at the surface and the only thing the wing should be doing at the surface is compensating for the weight of the gas in the bottle. AL80 for warm water is just over 6lbs. All weight should be ditchable for that. Personally all I'd do is just put a normal weight belt on with two 3lb weights and call it good.

You don't mention your tank size in the cold stuff, and since you're dry you have to assume 0 inherent buoyancy in the drysuit. More has to be ditchable here if you want to go that route, BUT you also have two forms of potential buoyancy at the surface, so you can go either way. Switch to stainless steel cam bands, those are good for a pound a piece, consider going to a single tank adapter, good for 2lbs as standard, or up to 8lbs for a weighted one, most of these have removable weights so you can take them out if need be. Puts you at 14lbs, with 12lbs left for ditchable which is about what you want for that type of diving and you can put that on a regular weight belt or in pockets if you want. I really dislike weight pockets because they take up quite a bit of real estate on the waist belts and if you go into technical diving you won't be using them, so best to get in the habit of not using them.

Now looking at what you have. You can keep the pockets you have and move those to the very back and that's a nonissue, but every time you switch, you have to unthread everything to get the permanent weights off so ma as well just use a small weightbelt. It is only 16lbs which isn't bad and not only helps during tank swapping by having less weight on there, it also allows it to be ditchable and 16lbs in the event of a drysuit failure or wing failure is that much less you have in either one. You are technically over the wing limit with your current configuration with an AL80, so in a drysuit failure you have to dump quite a bit of lead to help it keep up. Conversely that amount of air in the drysuit makes it very difficult to maneuver around and increases risk of a neck seal burp.

Random consideration, but consider moving to small doubles for the PNW. You get quite a bit of weight from the crossbar/bands and the extra tank, and lp72's don't weight much more than a single 130.

Lots of GUE/UTD type divers up in that neck of the woods, get with them and let them help you in person, it will be a lot more valuable than us guessing on the internet

 

[jzipfel]

Thanks all. It appears that it is going to be a trial and error process.

Why would you want to drop more weight than is needed to get neutrally buoyant? Is there a situation where you would want to drop 20 pounds of weight? An other thing to think about is what concentrating all your weight in one place does to your trim. That might work for a few people but not most.

Only want ability to drop to ensure positive buoyancy on surface. As TS&M states " irretrievably positive on the surface" in the event that other events/circumstances prevent me from this otherwise.

Regarding placement, I have moved weights around and found this to be the most comfortable and no problems with trim. Could always use improvement, but none the less...

The large weight pockets you are considering, do they let you easily pull out individual weights for dumping ? If not, how about putting 2 small XS weight pockets next to each other on each hip ? Each one holds 4-5 pounds letting you dump in 4-5 pound increments.

Not enough real estate on the waist band for more than one pocket. I have a 32 inch waist so not much strap to deal with.

I can only think of two situations where you might want to drop weight. One is a dry suit flood with a failed wing (and we don't normally plan for two major failures), and the other is an emergency where you want to be irretrievably positive on the surface. Assuming that you are out of gas, and therefore unable to power inflate your wing, and that your mental status doesn't permit oral inflation, you need only drop enough weight to be positive. Since, correctly weighted, you start the dive negative only by the weight of the air you intend to breathe, you need only drop that much weight, or a bit more. Unless you are using 130s or doubles, the 8 pounds you have easily ditchable will do it.

I am again probably overthinking. I dive single Faber 95. Possibly due to the fact I dive with my 14 year old son, I can sometime over-think safety.

Addressing the ditchable weight first. You want to be able to ditch the total weight of air in the tank, not much more in a wetsuit. Remember that you are neutral at the surface and the only thing the wing should be doing at the surface is compensating for the weight of the gas in the bottle. AL80 for warm water is just over 6lbs. All weight should be ditchable for that. Personally all I'd do is just put a normal weight belt on with two 3lb weights and call it good.

I don't use a wetsuit in waters above 72. I have Lavacore which is neutral. AL80 is typical for when warm water diving so I'm pretty sure the two 3 lb weights in pockets on the waist work well for my needs.

You don't mention your tank size in the cold stuff, and since you're dry you have to assume 0 inherent buoyancy in the drysuit. More has to be ditchable here if you want to go that route, BUT you also have two forms of potential buoyancy at the surface, so you can go either way. Switch to stainless steel cam bands, those are good for a pound a piece, consider going to a single tank adapter, good for 2lbs as standard, or up to 8lbs for a weighted one, most of these have removable weights so you can take them out if need be. Puts you at 14lbs, with 12lbs left for ditchable which is about what you want for that type of diving and you can put that on a regular weight belt or in pockets if you want. I really dislike weight pockets because they take up quite a bit of real estate on the waist belts and if you go into technical diving you won't be using them, so best to get in the habit of not using them.

I dive with a single Faber LP95. I might give the STA and some weigh back there a shot. As I mentioned earlier, when I tried placing weight on the cam bands (both high and low) I just felt like I wanted to turtle, so off they went and placed them up front. However, more weigh close to the body and spread out along the spine might work well.

Now looking at what you have. You can keep the pockets you have and move those to the very back and that's a nonissue, but every time you switch, you have to unthread everything to get the permanent weights off so ma as well just use a small weightbelt. It is only 16lbs which isn't bad and not only helps during tank swapping by having less weight on there, it also allows it to be ditchable and 16lbs in the event of a drysuit failure or wing failure is that much less you have in either one. You are technically over the wing limit with your current configuration with an AL80, so in a drysuit failure you have to dump quite a bit of lead to help it keep up. Conversely that amount of air in the drysuit makes it very difficult to maneuver around and increases risk of a neck seal burp.

Random consideration, but consider moving to small doubles for the PNW. You get quite a bit of weight from the crossbar/bands and the extra tank, and lp72's don't weight much more than a single 130.

Lots of GUE/UTD type divers up in that neck of the woods, get with them and let them help you in person, it will be a lot more valuable than us guessing on the internet

You mention technically over the limit for the 32lb wing. 6 lb wing + 20 lb lead + 8.325 lb neg buoyant LP 95. I can see that is greater than 32 lb, but I still have to exhale, deflate wing and give a little kick to get below 10 feet. Then at 500 PSI (for arguments sake) tank is neg 1.2 lb so now I'm at 27.2 lbs. Thoughts?

Moving to doubles is definitely not in the cards in the near future. New wing, manifold, 1st stage, tanks, whew! I am holding on by a thread right now with the wife. Also, I have a 14 year old son who is my buddy and don's see a purchase for both of us.

 

[TSandM]

jzipful, where are you in the Northwest? If you're in the Seattle area, or dive here, I'd be happy to meet up with you and take a look at your setup and how it works for you in the water.

 

[tbone1004]

with an LP95 you're even worse, keep in mind if you have SS cam buckles, they weigh 1lb each and that isn't counting the regulator, which can easily weigh in at 3lbs for a singles setup... Call it 10lbs for the rig with plastic cam bands and that includes any misc stuff, you have 12lbs of non-ditchable weight, and 8.5lbs of tank. You are right at the limit of that wing with the weight ditched, so it can barely keep itself afloat assuming plastic cam bands and the weight ditched with a full tank. With an empty tank it's less bad, but even empty empty you can't keep the rig at the surface without ditching weight *it's 32lbs, but with an 8" tank diameter you're loosing a bit of lift*.

Some weight has to come off of that rig to be balanced/safe. You have ditchable weight, but it likely isn't enough to keep you at the surface with a wing failure.

here's some quick fuzzy math.
Drysuit requires 20lbs of lead *14lbs differenceof exposure + 6lbs difference in AL80 to LP95* shouldn't require any "kicking down", just deflate it and inflate to where you're comfortable once at depth, if you actually need more lead, then add it, you're diving in cold a$$ water, no one is going to harp on you for being a bit overweight in a drysuit because you want more air in there to stay warm*

You with an AL80 require 12lbs, all in salt water. That's a bit more than you should be needing unless you have a lot of bioprene, most people should be able to just dive the SS BP/W and not have to wear anymore, might question that weighting...

You have a 32lb wing which can only be reliably filled to somewhere around 28lbs or so due to use with an 8" tank. DSS is the only company I know that actually calculates their wing lift based on actual water volume when mounted to the plate with an 8" tank. The rest are usually a few lbs heavy.

Tank with regulator assuming regular not cave fill, is somewhere around 10ish lbs negative. Backplate with hog harness assuming plastic cam bands is 6lbs, so you have absolute max of 14lbs of lead total that can be nonditchable to maintain a safe rig where it can float on the surface. Again, drysuits have to be assumed to have 0 inherent buoyancy because of a neck seal, dump failure. Currently require 20lbs of lead with 12 of it fixed, right at 28lbs assuming nothing else clipped, plastic cam bands, and a normal sized regulator set.

32" waist means not a whole lot of real estate to play with. Pockets are ideally pretty far back so they are in your slipstream and not too much in the way so I'd slide those all the way back and then put your hip D-rings back there to hold them in place. Personally I would make more ditchable and wouldn't weave any lead onto the waist belt. Put the 8lbs in the pockets and leave that there, put the rest on a regular weight belt. You can ditch the pockets individually which allows you to compensate for a wing failure but still maintain the weight required for your drysuit, and if you have a suit failure, you can drop the weight belt which will allow you to comfortable stay at the surface. Rubber freediving belts are best for this, and make sure you always put the weight belt on LAST when using any rig with a crotch strap

 

[TSandM]

Almost everybody I know who uses a weight belt with a backplate and a dry suit puts the weight belt on first. The theory is that it's a double failure, to lose the wing AND the suit for buoyancy, so ditching lead should be a very, very rare occurrence. And putting on a heavy weight belt with a big tank OVER the crotch strap is really challenging -- I know, because we make our students who are diving wet do it.

 

[jzipfel]

jzipful, where are you in the Northwest? If you're in the Seattle area, or dive here, I'd be happy to meet up with you and take a look at your setup and how it works for you in the water.

Thanks Lynne. I'd love to take you up on the offer at least to meet more dvers. I live in Issaquah so dive up and down the Sound. Life is over the top crazy right now but would love to contact you and dive. Hopefully mid June things will settle down in life and the vis will improve by then too.

Thanks much

---------- Post added May 18th, 2015 at 02:01 PM ----------

32" waist means not a whole lot of real estate to play with. Pockets are ideally pretty far back so they are in your slipstream and not too much in the way so I'd slide those all the way back and then put your hip D-rings back there to hold them in place. Personally I would make more ditchable and wouldn't weave any lead onto the waist belt. Put the 8lbs in the pockets and leave that there, put the rest on a regular weight belt. You can ditch the pockets individually which allows you to compensate for a wing failure but still maintain the weight required for your drysuit, and if you have a suit failure, you can drop the weight belt which will allow you to comfortable stay at the surface. Rubber freediving belts are best for this, and make sure you always put the weight belt on LAST when using any rig with a crotch strap

This is my next test. The pockets are already all the way back. Planning on putting two 4 lb leads on each side of the weight belt. Then I would have total of 16 lbs to ditch if total wing failure.

Thanks for the thorough calcs on weight. Much appreciated. I think/hope I'm on the right track