weights with no suit

[TMHeimer]

Here's an easy one. I've not yet dived in water without my 7 mil wetsuit. Plan a possible trip to Turks & Caicos, where no doubt I would use swim trunks and a T shirt. I am 205 pounds. What amount (in pounds) of weight should I use? Assume aluminum 80s would be the rentals, but what about steel tanks as well? Thanks for advice.

 

[Thalassamania]

How tall are you and how fat? When I was in college I weighted almost exactly what I do now, then I sank if I got in the pool, now I need four or five lbs of lead to be neutral. (I'm 6'2" and 240).

 

[LeadTurn_SD]

How much weight do you use with your 7mm?

A 7mm can require as much as 20lbs (or more) ballast to offset it's buoyancy.

Much depends on your body composition, and, errrr, how much "bioprene" you have . If you have fairly low body fat, you may be neutral-to-negatively buoyant. Most folks are somewhat positive in salt water, and the higher the body fat, the more positive.

An Al80 is around -1.8 lbs when full, and around +4 lbs when empty. A typical rental BC might be +3 lbs, a typical regulator about -2 lbs. Steel tanks will generally be negative, how much depends on the tank.

What does all this mean? You may be able to dive without weights in a t-shirt using an Al80, but most folks probably still need a few pounds to stay neutral at the end of the dive.

The only real way to know is to perform a buoyancy test when you get there.

Have fun!

 

[Ed Hatfield]

I have a son in Halifax in the Navy. I can't even imagine getting in that frigid Atlantic water without a dry suit. I guess being a 'wuss' Ontario diver I don't have the 'nads'. I won't even dive the Caribe without a full 3mm. You probably will do just fine with a T-shirt and shorts. The weight is a personal adjustment and your first dive is going to be a 'check-out' dive anyway. Most dive operations have the check out dive as mandatory so you might as well wait (weight) till then. Since you don't nomally take your weights with you (all supplied with the tank), you may as well relax and figure it out then. ENJOY YOUR VACATION.

 

[rstofer]

I dove in a T shirt and shorts while hanging around Singapore, Malaysia and Thailand. I needed 6# with an Al 80 tank. 6'1", 210# The jacket style BC had 38# of lift! No problem floating on the surface!

Richard

 

[TMHeimer]

Thanks guys. With my 7 mil, I need 34 pounds with my steel 120 and use 40 with an aluminum 80. That sounds like a lot, but it's true. My instructor couldn't believe it when I did the PP Bouyancy course. What is a check out dive on a boat? I thought that meant your 4 OW course dives. I have been on quite a few charters in Fla. and never heard that term used. They just made sure all were ready to go, etc. I wish I did own a dry suit, as we had to stay North this winter. 20 mins. in 33F water is tough.

 

[ae3753]

RE check out dive - Some operators will do a first dive in a shallow reef to allow people to get their weighting correct and check on people's comfort in the water before proceeding to more "advanced" sites.

 

[mselenaous]

If you took the PPB Bouyancy class, then the following guidelines should have been covered. The guideline below is from the PADI Bouyancy class and should help with a starting point, but since we are each individuals with different body compositions there is a bit of trial and error to fine tune your bouyancy to find that "sweet spot" each time you change gear/climates/seas, etc.
That said, when I worked in warmer climates, I usually started folks with aluminum tanks in about 8-10 lbs and adjusted down to 4-6 or up from there rarely exceeding 12 lbs. If you can get a steel tank, you might not need any additional weight.

Basic Weighting Guidelines
How much weight do I need? This is a tough question every diver faces from
time to time. Although only a buoyancy check precisely determines the proper
amount of weight needed, here are some basic weight guidelines that will get
you started. These guidelines are based on individuals of average build, diving
in salt water. Lean individuals or individuals diving in fresh water may need less
weight, heavy individuals may need more.
Basic Guidelines:
Exposure Suit Type Begin With
1. Swimsuit or dive skin 0.5 - 2 kg/1 - 4 lb.
2. Thin (3 mm/1/16 inch), one-piece 5% of your body weight
wet suits shorties or jump suits
3. Medium-thickness (5mm/3/16 inch), 10% of your body weight
Two-piece wet suit
4. Cold-water (7mm/1/4 inch), two-piece 10% of your body weight,
wet suit with hood and boots plus 1.5 - 3 kg/3 - 5 lb.
5. Neoprene dry suits 10% of your body weight,
plus 3 - 5 kg/7 - 10 lb.
6. Shell-style dry suits* (using light-weight, 10% of your body weight,
nonfoam underwear) plus 1.5 - 3 kg/3 - 5 lb.
7. Shell style dry suits* (using heavy-weight 10% of your body weight,
or foam underwear) plus 3 - 7 kg/7 - 14 lb.
* Regarding shell-style drysuits the lead needed beyond 10% of your body weight is
primarily determined by the buoyancy of your underwear. The buoyancy of different
underwear types varies greatly.
Conversion Estimates for Salt or Fresh Water
Convert from salt water to fresh water (or vice versa) using the following estimates.
Amount of Weight to Add
(Fresh Water to Salt Water) or
Body Weight Subtract (Salt Water to Fresh Water)
45 - 56 kg/100 - 125 lb. 2 kg/4 lb.
57 - 70 kg/126 - 155 lb. 2.3 kg/5 lb.
71 - 85 kg/156 - 186 lb. 3 kg/6 lb.​

86 - 99 kg/187 - 217 lb. 3.2 kg/7 lb.

 

[Gilldiver]

An aluminum 80 should be just about neutral with 300 PSI when the reg and BC are on it. If you get all the air out of the BC that is. Add any do-dads you might carry and you should be slightly negative.

Go with about 4 pounds of weight and see how it goes. You may be able to drop down to 2 or none with a suit and T-shirt.

A steel tank (other then a vintage 72) should be negative at 300 psi and dressed out, so I'd give it a try with no extra weight.

The above is with no air in the BC, which many divers just don't seem to grasp.

Of course you can Skiny SCUBA, but the harness can chafe and we don't want to know if you go fishing with that little worm.

 

[LeadTurn_SD]

Thanks guys. With my 7 mil, I need 34 pounds with my steel 120 and use 40 with an aluminum 80. That sounds like a lot, but it's true. My instructor couldn't believe it when I did the PP Bouyancy course. What is a check out dive on a boat? I thought that meant your 4 OW course dives. I have been on quite a few charters in Fla. and never heard that term used. They just made sure all were ready to go, etc. I wish I did own a dry suit, as we had to stay North this winter. 20 mins. in 33F water is tough.

You'll probably need to wear a bit of weight when diving with an AL80, even in just a t-shirt and swimshorts based on the info above.

You can do a buoyancy check pretty quickly at the start of your first dive: With a full tank slowly add weight until you float at eyelevel holding a normal breath, then add an additional 4-5 lbs (to make up for air used during the dive), then fine-tune it at the end of the dive. Your DM should help you with this.

Good luck and have fun!