It works for me.
weighting between fresh and salt water
- Thread starter arcticat99
- Start date
Please register or login
Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
- Ability to post and comment on topics and discussions.
- A Free photo gallery to share your dive photos with the world.
- You can make this box go away
It works for me.
underH2Oman
Contributor
Buoyancy characteristics change from person to person. I am 6ft and weight 235 pounds. in a 3mm shorty I do not wear weight in fresh water but use 4 in salt.
Carrying extra weight when diving can have a large effect on buoyancy. The changes are happening to the added air you need to carry to compensate for the extra weight as well as the suit.
I would recommend you try and take a cylinder to the pool that only has 500psi in it and then see how much weight you need to slowly settle under the water when you exhale your breath (no air in the BC). If you sink at more than say 1ft per second you have too much lead. reduce the weight and try it again.
Carrying extra weight when diving can have a large effect on buoyancy. The changes are happening to the added air you need to carry to compensate for the extra weight as well as the suit.
I would recommend you try and take a cylinder to the pool that only has 500psi in it and then see how much weight you need to slowly settle under the water when you exhale your breath (no air in the BC). If you sink at more than say 1ft per second you have too much lead. reduce the weight and try it again.
We both are right.
There are different body structures and forms. I'm lucky that the standard wetsuit for my weigh fits me as paint.
I've meet many people in the dive school with different body mass and what's too much for some is too little for other, perhaps with the same weight. Muscle mass, fat, fitness, air capacity, the way you breathe, gear, experience and a lot of other things contribute to the amount of weight needed to be neutral underwater.
Of course that a weighting calculator will be accurate in some cases and completely unaccurate in others. Everyone is different. However, some tendencies can be seen in the way people dive. Those tendencies can be drawn in an algorithm that could predict the amount of lead some one could need as a starting point.
mi000ke
Contributor
- Messages
- 1,142
- Reaction score
- 1,734
- Location
- Massachusetts & Grand Cayman Island
- # of dives
- 200 - 499
Different people are indeed different, and the weighting needs can be quite surprising. In my years of instructing, I have encountered many experienced divers who will tell me flat out that they need a certain amount of weight, and that is that. Somehow after we work for a while, they discover they only need about half that weight after all.
- Messages
- 16,400
- Reaction score
- 5,219
- # of dives
- 1000 - 2499
I use 5 pounds as a difference between salt/fresh. Agree amount of weight needed differs (maybe a lot) between people. See my "Lotsa Weight" thread below here.
If you want to be more precise, if you were perfectly weighted in fresh water, you will need to add a little less than 3% of your total weight (body, tank and all) to dive in salt water. The suggestions you are getting of 4-6 pounds are in that ballpark. If you are a little overweighted in fresh water (and almost everyone is actually at least a little overweighted), then you will probably do fine at the lower end of that spectrum.
thatmark
Registered
Arcticat,
I just went through a similar round of experiments and calculations.
Last week I was in Nassau, Bahamas for work and planned a day off to do my first saltwater diving. All of my diving to date has been here in MD and VA in fresh water with my SS BP/W, HP100, 5mm full wetsuit, and 8# on a weight belt. I'm 6' tall and weigh 230#. Based on my research I decided that I would buy a Sharkskin for the warmer water instead of a shorty or a 3mm full suit (which were the other popular opinions). I couldn't make getting the suit and getting to the pool line up, but since it's neutrally buoyant, I hit the pool in shorts and a t-shirt and did a weight check with my gear and an AL80 which is what the dive op (Stuart Cove's) in the Bahamas would be supplying. Once I adjusted for the weight of the air in the tank I needed 2-3# in the pool. Having read everything I could find here on SB, I did the calculation of .025 x my total weight with gear and came up with 6-7# additional that I would need for the salt water.
Then I called Stuart Cove's and asked if there was a place I could do a weight check before the boat went out. They were a bit surprised at the request, but happy to accommodate me coming by the afternoon before I was going out on the boat. They set me up with a tank with 500 PSI left in it, a weight belt and assorted weights, and let me hop in to the canal where they dock their boats. I little trial and error and 8# was the answer. So, the math was proved to work, but more importantly I was much more comfortable knowing I wouldn't be jumping off the boat at the first dive site and needing to adjust. If you're like me it will be well worth the extra time. If the day before isn't an option with your trip, maybe you can get where you're going early the day of and do something similar.
Hope that helps!
Mark
I just went through a similar round of experiments and calculations.
Last week I was in Nassau, Bahamas for work and planned a day off to do my first saltwater diving. All of my diving to date has been here in MD and VA in fresh water with my SS BP/W, HP100, 5mm full wetsuit, and 8# on a weight belt. I'm 6' tall and weigh 230#. Based on my research I decided that I would buy a Sharkskin for the warmer water instead of a shorty or a 3mm full suit (which were the other popular opinions). I couldn't make getting the suit and getting to the pool line up, but since it's neutrally buoyant, I hit the pool in shorts and a t-shirt and did a weight check with my gear and an AL80 which is what the dive op (Stuart Cove's) in the Bahamas would be supplying. Once I adjusted for the weight of the air in the tank I needed 2-3# in the pool. Having read everything I could find here on SB, I did the calculation of .025 x my total weight with gear and came up with 6-7# additional that I would need for the salt water.
Then I called Stuart Cove's and asked if there was a place I could do a weight check before the boat went out. They were a bit surprised at the request, but happy to accommodate me coming by the afternoon before I was going out on the boat. They set me up with a tank with 500 PSI left in it, a weight belt and assorted weights, and let me hop in to the canal where they dock their boats. I little trial and error and 8# was the answer. So, the math was proved to work, but more importantly I was much more comfortable knowing I wouldn't be jumping off the boat at the first dive site and needing to adjust. If you're like me it will be well worth the extra time. If the day before isn't an option with your trip, maybe you can get where you're going early the day of and do something similar.
Hope that helps!
Mark
OP
arcticat99
Contributor
unfortunately my dives are coming off a cruise ship so I wont be able to do that but good news is im doing 3 different dives so I can take from my first day and adjust for the second but these numbers give me a great place to start ,fyi first dive site is turks and caicos 2 dives then grand cayman for 2 dives then Cozumel for 2 looking forward to it
Similar threads
