weighting ?'s in salt water

[Navihawk24]

I have been certified for a year now. I did 14 freshwater dives and am properly weighted at 28lbs. I tried 24 but could not stay down when my tank was empty. (500) I was wearing a farmer john 7mm in cold water. I did my first 4 salt water dives in the carribean in dec of 2010 and curiosu about what how much weight i need. When i dove in st thomas i wore 26lbs and felt way heavy. When i dove gran turk the divemaster said i dove too heavy then put me down to 14lbs. Felt decent. Here is my equipment for the carribean. I weigh 188, 5' 5" henderson lycra 1mm, 3mm shorty or full wetsuit, 80 alum tank, seaquest tech bc integrated weighting with trims, 1-3 mm henderson gloves, aqualung octo, atomic b1 regulator, cobra dive computer and compass. any estimates or help would be great. thanx

 

[spectrum]

Navihawk24

There won't be any useful relationship between the cold and warm water gear so you need to get the warm water gear in the water for a check, fresh will work. if you can get into a pool long enough to really saturate things and be down to a light cylinder (start with a short fill) you can find that perfect configuration.

Once you're happy with the whole deal you need your total dry diver weight, just as you would be before making the dive in fresh water. You, gear, weights, the whole thing. Divide that number by 40 and add it to your fresh water lead.

More here.

Pete

 

[ScubaSteve1962]

Here's a site that may help you out
Scuba Buoyancy Masterclass 4of9 - Assessing Your Weight RequirementsScuba Tech Philippines

 

[aquaregia]

I use about a third of the weight with a 3mm full as I do with a 7mm full.

 

[lulubelle]

I have found that despite the many models out there for estimating weight requirements, the only valid tool I have found is an in water weight check.

The site Incognegro linked to was solid in it's description of how to do them properly. You are not average based on the stats you give, and people's body composition varies so much anyway, so I would imagine that you will be better off guestimating a proper starting point but doing a proper weight check for validation. Start with the 14 you used in Turks and work from there. I am guessing that you are still a bit heavy for salt water diving in the gear you describe.

I'll sometimes do a weight check in fresh water if there has been a major change in my gear. Or I will tweak it a little on my dives and validate it on my safety stops by handing off weight to my buddy. I have been slowly losing weight and adding muscle for the past year, so I revisit my requirements every few months, even given the same gear. On a recent trip to the Maldives, I had to use kg weights, so I rounded up the first dive, was a tad heavy, and then down the second and was dialed in.

 

[boulderjohn]

I use about a third of the weight with a 3mm full as I do with a 7mm full.

I agree, and you are using a farmer john, which should have an even bigger difference. Everyone is different, and the difference from one person to the next can be surprisingly great. When you get the opportunity, to a good weight check. I suggest starting with maybe 8-10 pounds and see how it goes from there.

 

[DivemasterDennis]

Let's start by agreeing with the last two posts- sort of. When yo8u are your dive destination wearing the gear you will be diving in, do a weight check in the water in which you will be diving. Many things affect how much weight you will need other than you body weight and height. Given the data you present, I would expect you to use no more than 16 pounds, and perhaps a little as 12. BUT..as you pointed out with great insight, you tank weighs less at the end of a dive than at the start, and that difference is not totally set off by you exposure suit getting saturated. So if you land at 18 pounds, so be it. Or if 10 pounds lets you hover easily at the end of the dive, that's fine too. It is as bad to be underweighted a s overweighted, so take time to do the on site buoyancy check, and adjust as needed. Have a great trip!
DivemasterDennis, scubasnobs.com

 

[boulderjohn]

. Everyone is different, and the difference from one person to the next can be surprisingly great. When you get the opportunity, to a good weight check. I suggest starting with maybe 8-10 pounds and see how it goes from there.

Given the data you present, I would expect you to use no more than 16 pounds, and perhaps a little as 12. BUT..as you pointed out with great insight, you tank weighs less at the end of a dive than at the start, and that difference is not totally set off by you exposure suit getting saturated. So if you land at 18 pounds, so be it. Or if 10 pounds lets you hover easily at the end of the dive, that's fine too. It is as bad to be underweighted a s overweighted, so take time to do the on site buoyancy check, and adjust as needed. Have a great trip!

Well, I guess that shows how different everyone is. I am much bigger than the OP and should need more weight. If I have a 3mm full suit in the ocean, I use 8 pounds.

 

[aquaregia]

The thing with responses like "do a weight check" is that you're often offshore, on a boat, with people waiting around. You can do a rough weight check, but if you sit around checking from 20# all the way down to 6# a pound at a time, people around you are going to be mad. Ballpark recommendations are very valuable for not wasting people's time.

 

[Ste Wart]

Well, I guess that shows how different everyone is. I am much bigger than the OP and should need more weight. If I have a 3mm full suit in the ocean, I use 8 pounds.

Ah, never underestimate comfort in the water. Once when DMing I tried to give a larger lady a rather hefty weightbelt in my belief that it would be what she needed. She insisted on only 4 kilos for a 5mm suit. Then produced her instructor card.. I left with head suitably hung in shame.

To the OP. DivemasterDennis has a good estimation for your weight. A 3mm full plus an Al80 will need approx 5% of your bodyweight plus 3- 6 lbs. Which would be around 12-14ibs.