How much weight?

[flots am]

Need to guess : or just add 8 lb or calculate proportionally:
Configuration 1 : Fresh water 7 lb :-: Salt water 7 + 8 = 15 lb
Configuration 2 : Fresh water 7+12 = 19 lb :-: Salt water 7 + X lb
Configuration 3 : Fresh water 7+16 = 23 lb :-: Salt water 7 + Y lb
7 + X = (19 x 15 / 7) = 41
X = 41 - 7 = 34 lb
7 + Y = (23 x 15 / 7) = 49
Y = 49 - 7 = 42 lb
. . .
Suggestions? Corrections ? Comments ?

Yes. You're missing the point.

The only way to actually know how much weight you need is to do a buoyancy check.

flots.

 

[Oldbear]

I would say a given % of a diver's weight or a calculation for a given environment/equipment configuration is a fairly good estimated starting point for a new diver for those diving circumstances...STARTING POINT.

Nothing replaces getting wet.

An example is another instructor here on the island and myself. We are both similar weight and height, dive the same environment with the same equipment configuration. So a percentage of body weight would indicate that we should dive with relatively the same weight.

Not happening...

He is a policeman with that 6% body fat and I am an office rat and just a little bit more "fluffier"

I don't think he even uses weight and I dive with 16 lbs.

Nothing replaces getting wet!

 

[scubadada]

I am 6' 275lbs, chunky but carry my weight well , lol. I will be diving with a steel 120 weighs 39lbs. I will also have a alum 30 for emergency air. Wetsuit will either be a 3 mm or a 6mm and it will be in saltwater in 60-120'. Where should I start around. I was thinking about 16lbs. Correct me if i'm wrong. Thanks

Hi oledenred,

You have not revealed your number of dives, my first assumption would have been that you know your approximate weight requirement, I guess this is wrong. I'm about 80 pounds lighter than you, with a steel tank, I use only a couple of pounds with a 3 mm wetsuit and about 8 pounds with a full 5 mm. Your mileage may vary. You really want to just be able to hold your safety stop at the end of the dive with an essentially empty tank and make a controlled ascent afterward. Give it a try, you can always eliminate excess weight, that should be your goal. Good luck

 

[NAM001]

Lets start with this. how much weight so you need with your wet suit in fresh water? + ______ #
Bp/w -1 al -6 steel - 2# for webbing and hardware - ______ #
Tank 400psi buoyancy -1# ( -2 - 1) = -3 +/- _______#
Regs - 3 #
Add it up if teh answer is a + than add lead if negative wear more suit take less gear or live with it.

Jockey equipment till numbers add to zero TOTAL _____0______


Put all you gear on and weigh your self ________# X .025 = (conversion between fresh and salt water) +/- _______#
fresh to salt add........ salt to fresh minus
Add it all up---------------------------------------------------------------------------------------------------- ________#
For me in shorty it is +11 in fresh
al bp/w -3
400psi -3
2 regs on H valve -6
TOTAL -1 I am -1 in fresh water in my shorty. Lighter in full 3mm suit.

250# plus gear scale weight 325# (x .025) =8# 0 for freshwater 8 additional for salt
(1# for every 40 scale weight)

If my original buoyancy was done in salt water there would be 0 correction for salt and 8# LESS needed to go to fresh.

With the example i gave the lead requirement was zero.

Lets say i had on my farmer john 3mm It is +19 and i am +3 for a total of +22.

The first line would be +22 and not +11 the end result would be 10# of lead. In this event i would have changed to a steel bp and wore 5# lead.

I am 6' 275lbs, chunky but carry my weight well , lol. I will be diving with a steel 120 weighs 39lbs. I will also have a alum 30 for emergency air. Wetsuit will either be a 3 mm or a 6mm and it will be in saltwater in 60-120'. Where should I start around. I was thinking about 16lbs. Correct me if i'm wrong. Thanks

 

[Roman_66]

Yes. You're missing the point.
The only way to actually know how much weight you need is to do a buoyancy check.

It is true and I agree, this is why I wrote:

I don't have option to check weight in salt water before trip ....... with my new configuration.

I think most recreational divers went to first dive after big configuration change with kind of guessing.
I was interested how to recalculate (about, not exactly ! ) weights needed for salt water if I know needed weights for fresh water with the same equipment.
And looks I received the answer, thank you:

Put all you gear on and weigh your self ________# X .025 = (conversion between fresh and salt water)
(1# for every 40 scale weight)

I think that all my gear and myself about 320 - 340 lb and additional 8-10 lb to weights, which I had in fresh water, will be enough for salt water.
At least for first dive, at the end of dive I will try to check weights according to protocol.

 

[Rich Keller]

There are too many variables involved so the best way is to do a buoyancy check wearing the exact equipment you plan to use. Apply this drown proofing technique Drownproofing with you wearing all of your equipment to find out exactly how much weight you need on the surface. This is what we did before BCDs were invented. From there you need to account for the weight difference between a full and empty tank Scuba Cylinder Specification Chart from Huron Scuba, Ann Arbor Michigan and suit compression. Using this method you will only need the BCD to make minor adjustments during your dive. This will also allow you to use a smaller, lower profile BCD that will not waist much air during the dive and should the BCD fail you will be far less dependent on it to survive.

 

[wspalding]

There are too many variables involved so the best way is to do a buoyancy check wearing the exact equipment you plan to use. Apply this drown proofing technique Drownproofing with you wearing all of your equipment to find out exactly how much weight you need on the surface. This is what we did before BCDs were invented. From there you need to account for the weight difference between a full and empty tank Scuba Cylinder Specification Chart from Huron Scuba, Ann Arbor Michigan and suit compression. Using this method you will only need the BCD to make minor adjustments during your dive. This will also allow you to use a smaller, lower profile BCD that will not waist much air during the dive and should the BCD fail you will be far less dependent on it to survive.

Yep. I used the rule of thumb method today to estimate weight and was grossly overweighted. There is no good shortcut to getting the weight right, although by rule of thumb you get a reasonable starting point.


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