Salt Water Weighting Question

[bladephotog]

I'll be diving salt water for the first time in November and am wondering about how much extra weight I'll need? I'm 5'7", 163 lbs and normally use 14lbs with a 5/3 and hood and gloves. For this trip I'll be wearing a 3 mil with thinner hood and gloves. Is there a formula for fiquring this out? I'm hoping to avoid jumping off the boat and not having enough weight. Maybe the charter captain will let me do a quick bouyancy check?

Any help is much appreciated. Thanks.

Andy

 

[mike_s]

I'll be diving salt water for the first time in November and am wondering about how much extra weight I'll need? I'm 5'7", 163 lbs and normally use 14lbs with a 5/3 and hood and gloves. For this trip I'll be wearing a 3 mil with thinner hood and gloves. Is there a formula for fiquring this out? I'm hoping to avoid jumping off the boat and not having enough weight. Maybe the charter captain will let me do a quick bouyancy check?

Any help is much appreciated. Thanks.

Andy

I'd guess take an extra 4 lbs when you get in the water for your
bouyancy check. You can go from there +/- a pound or two.

 

[DandyDon]

I'd guess take an extra 4 lbs when you get in the water for your
bouyancy check. You can go from there +/- a pound or two.

This is why I always carry a couple of 1# soft weights and a couple of 2# softs. Boats often have plenty of larger weights, but not the smaller ones. 'Course, it's another 6# in my dive bag. :11: They sure come in handy, tho'

Be careful about just dropping them in your BC pocket, tho'. I've seen them fall out many times. Secure them well.

Another trick is to use cable ties to connect bolt clips to a couple of 1# weights, and clip thse to the bottom rings on your BC. When you're at 500 PSI in your tank, you can take one or two off to pass to the boat, and see if you're still heavy enough. I often pass these to others struggling to do their safety stops on the first dive underweighted. :shades:

 

[oceancrest67]

It takes some time and effort to finesse the weighting issue. A good diver understands his or her weight range depending on the kind of suit, conditions, equipment (steel or Aluminum tanks) and / or fresh water diving vs. salt water diving. With a thicker wet suit in salt water, aluminum tank, the diver will be more buoyant = additional weight will be needed. With a thinner wet suit in fresh water, steel tank, the diver will be less buoyant = less weight is needed. Most divers learn their "margin" of weight depending on the conditions.

 

[jbisjim]

In cold water, using alum tanks I weight "newer students" I wight them 10% plus 8-10 lbs. Using 5 to 7 mill Johns, hoods, gloves, etc.

**discalimer** This is the place i start. Adjusting as needed.

edited for clarification for penny

 

[redacted]

I'll be diving salt water for the first time in November and am wondering about how much extra weight I'll need? I'm 5'7", 163 lbs and normally use 14lbs with a 5/3 and hood and gloves. For this trip I'll be wearing a 3 mil with thinner hood and gloves. Is there a formula for fiquring this out? I'm hoping to avoid jumping off the boat and not having enough weight. Maybe the charter captain will let me do a quick bouyancy check?

Any help is much appreciated. Thanks.

Andy

There is a "formula" but you will need more data.

You need to know your weight with all your gear that does not change. For many folks who just dive Al80s, that is all gear except exposure protection. It works out to about 270 pounds for me. And you also need to know the bouyancy of each configuration of exposure protection. I used a small mesh bag and an array of lead weights to measure the bouyancy of each piece of neoprene I use. My .5mm full suit is <1 lb, 3mm shorty is 4 lb, 5mm full is 11 lb, 3mm hood <1 lb, etc. Finally, you need to know how much weight you require in at least 1 condition. I knew that I required 0 weight in FW to be neutral with no neoprene. With that info, you can plan for any other condition.

The conversion between SW and FW is calculated base on your weight and the change in water density. FW density is 1.00 and SW is 1.027 (I call it 1.03 to keep the cipherin' easy.) So, in my case, I add 8 pounds when I go from FW to SW (.03 x 270 = 8.1). Then I adjust my weight further based on the neoprene bouyancy characteristics.

So, in your case at 163 lb, I'd estinmate you and basic gear at around 200 pounds. so your weight difference between FW and SW should be 6 lb. I'd guess your 5/3 to be about 10 lb bouyant, the hood and gloves to be another 2 lb, your 3mm about 7lb and the light hood & gloves to be 1 lb. You really should find a local pool to check these guesses and record the results in your log book. So, with your known 14 lb in FW with 5/3, hood & gloves; we can estimate you need 2 lb with no protection in FW. Add 6 lb for the conversion to SW and 8lb for the 3mm with light hood & gloves and you are looking at 16 lb total. Just to be safe, stick a 1 lb weight in your pocket and hand it to you buddy at the first rest stop and see how it feels.

Enjoy & "weight" that neoprene.

 

[Don Burke]

I'll be diving salt water for the first time in November and am wondering about how much extra weight I'll need? I'm 5'7", 163 lbs and normally use 14lbs with a 5/3 and hood and gloves. For this trip I'll be wearing a 3 mil with thinner hood and gloves. Is there a formula for fiquring this out? I'm hoping to avoid jumping off the boat and not having enough weight. Maybe the charter captain will let me do a quick bouyancy check?

Any help is much appreciated. Thanks.

Andy

If all you were changing was the water, it would be pretty simple, just add one pound for every thirty-seven pounds of overall weight. Changing the exposure protection makes it more complex than that.

I would find a pool somewhere and figure out the freshwater weight for the gear you are actually going to wear, then add one pound for every thirty-seven pounds of overall weight to come up with a saltwater weight. I would add an additional pound or two for the first dive since it is much easier to be a couple of pounds heavy than a pound light and salinity is not always what the books say it is. By the third dive you will have it dialed in pretty closely with no real effect on your trip.

Enjoy your trip.

 

[bladephotog]

Thanks for the great info everyone. I'll get in the pool and on the scale before I go. Now I'm off to dive 45 degree water on this wonderful 50 degree, drizzly Ohio day! Key Largo in two weeks! Let the countdown begin.