weighting "ball park" figure

[gomi_otaku]

I've been looking for the "formula" for weighting that I learned in OW class- for how much weight to use to "ballpark" before you fine tune. I did my OW 3 months ago in cold freshwater, but now I've moved to the west coast, to cold SALT water. I also did my OW in a BC, I now have a SS backplate to try and would like to get a good "guesstimate" for what size soft weights to get to start my fine tuning. In fresh water I used 28#, I know I need to add 5-7# for salt water, but then I have to take a 12# plate/STA into account...does that sound about right? I have approximately the same wetsuit- a 7mm Farmer John/Jacket, hood, gloves, boots. Does the "jacket" portion of the average BC add some positive bouyancy, which I would not have with the BP/Wing?
thanks,
gomi_

 

[djbobbyzee]

I've been looking for the "formula" for weighting that I learned in OW class- for how much weight to use to "ballpark" before you fine tune. I did my OW 3 months ago in cold freshwater, but now I've moved to the west coast, to cold SALT water. I also did my OW in a BC, I now have a SS backplate to try and would like to get a good "guesstimate" for what size soft weights to get to start my fine tuning. In fresh water I used 28#, I know I need to add 5-7# for salt water, but then I have to take a 12# plate/STA into account...does that sound about right? I have approximately the same wetsuit- a 7mm Farmer John/Jacket, hood, gloves, boots. Does the "jacket" portion of the average BC add some positive bouyancy, which I would not have with the BP/Wing?
thanks,
gomi_

Gomi,
First & foremost, I suggest the Advanced OW Peak Performance Buoyancy course. Depending on the Jacket style BC you used the Wing setup it sounds like you intend to use is going to be a world of difference. The jacket & backpack standard bc's are fairly neutral. I'm not sure what type of 'backplate' your using but it sounds like a tank.

For salt water, in a 7mm suit, the average is 10% of your body weight. I'd suggest going out with a buddy on some gear tests & playing around with the formula & working your buoyancy & breathing.

-Bobby

 

[Sideband]

12 pounds for a plate and wing is a bit much. My stainless plate is 6# and my stainless STA is about 2#.


Joe

 

[Spoon]

mine is 6lbs ss plate adn sta 1 lb

 

[spectrum]

I've been looking for the "formula" for weighting that I learned in OW class- for how much weight to use to "ballpark" before you fine tune. I did my OW 3 months ago in cold freshwater, but now I've moved to the west coast, to cold SALT water. I also did my OW in a BC, I now have a SS backplate to try and would like to get a good "guesstimate" for what size soft weights to get to start my fine tuning. In fresh water I used 28#, I know I need to add 5-7# for salt water, but then I have to take a 12# plate/STA into account...does that sound about right? I have approximately the same wetsuit- a 7mm Farmer John/Jacket, hood, gloves, boots. Does the "jacket" portion of the average BC add some positive bouyancy, which I would not have with the BP/Wing?
thanks,
gomi_

The 5/7 salt water boggie iis typical, your total dry weight multiplied by .026 is added for salt. Include you, all your gear and a charge of air in the total weight.

A jacket may be a few pounds positive, some more than others. Probably 1-3 in general. 1 heavy accesory like a 8/C light will cancel this.

Remember that a similar wetsuit may still be quite different in buoyancy depending on age, rubber etc.

+28 baseline
-12 plate/sta
+2 old jacket
+7 salt water adder
------------
25 pounds best guess, try 26 or 28 depending how close you think you were at 28 in the old configuation. If you took 30 for the 1st dive I wouldn't call you a fool given the wetsuit wild card.

Do a propper weight check at the end of the dive when it's all saturated and the tank is near 500 PSI. Bob plumb, crossed fins, get to eye level holding an average lung volume. Make sure to use a selection of removable weights that will let you find the right number. You will need to have some in pockets or integrated ditchables, not all laced on a web belt.

Pete

 

[herman]

I don't believe a " formula" that is anywhere close really exist. Everyone is different. For example, by the 10% formula, the one almost everyone uses, I should be diving with somewhere around 15-16 lbs in fresh water. With no wetsuit I actually dive with 2 in fresh and 6 in saltwater or 14 lbs less that the formula say I should. Do yourself a big favor, forget the formula and just do a good buoyancy check. I would also suggest you log your weights, equipment and impressions of the weight you used after each dive or at least after each diver where you changed anything. With the information logged you can look up a similar dive and have a pretty good idea what weight you need for the dive and equipment you intend to use.

 

[Gary D.]

Simple formula that works every time without fail.

Find a calm shallow area with the type of water you will be diving. Cold Pacific, Warmer Pacific, Cold Atlantic and so on.

Suit up like your going diving. Bring various size weights. Get into the water. If you float add weight. If you sink remove weight. Remember, Wright down or do both with the results.

Do the above with both full and low tank(s).

Go diving.

Gary D.

 

[Jeddah Aquanaut]

As a DM, I of course follow the regs when helping out instructors with OW students. After all is said and done, though, here's what I did (still do when changing tanks, BC's...lose/gain weight) to tweak my bouyancy: I'd carry some of my weights in the BC pockets. At the end of a dive, at 5m, I'd hang on the bar and dump all the air from the BC. I'd lay a 2lb weight, or 1 lb. If I still sank, I still had too much weight. I would not cut it TOO fine, but it helped me go down from almost 20 lbs (what MY OW instructor recommended, to 8-12 lbs, depending on what I've got. Anyway, I almost always carry 2-3lbs of extra weight above that what I need, as often a student or buddy will need during the dive, so I've got to spare. The formulas mentioned by others here are a good starting point, but start there to find what's right for you.

 

[spectrum]

Keep your type of diving in mind when deciding where to set your neutral point. If you're shore diving you may spend considerable time. especially at the end of a dive in fairly shallow waterless than 5m deep. That being said I can't think of a reason to ever be more than "eyeball buoyant" at the surface at the end of the dive at 500 PSI.

Pete

As a DM, I of course follow the regs when helping out instructors with OW students. After all is said and done, though, here's what I did (still do when changing tanks, BC's...lose/gain weight) to tweak my bouyancy: I'd carry some of my weights in the BC pockets. At the end of a dive, at 5m, I'd hang on the bar and dump all the air from the BC. I'd lay a 2lb weight, or 1 lb. If I still sank, I still had too much weight. I would not cut it TOO fine, but it helped me go down from almost 20 lbs (what MY OW instructor recommended, to 8-12 lbs, depending on what I've got. Anyway, I almost always carry 2-3lbs of extra weight above that what I need, as often a student or buddy will need during the dive, so I've got to spare. The formulas mentioned by others here are a good starting point, but start there to find what's right for you.