fresh water v salt water?

[jon m]

hey all
just got certified , and our classes (open water) were in cold fresh water with 7mil wets and all the gear to go with it... i was using 32lb of weight (6'2" @ 240lb) i was almost totally neutral with 700psi at end of 2cd dive, so i was about perfect. our first dive will be in hawaii next week... i assume shorty wets w/salt water... is there any way to estimate the weight difference? are there charts to give approx. weight?
thanks!!!
btw- any suggestions on a good dive for beginers in Kauii? don't really want to go deeper than 40-50'... thanks!!!!
-me

 

[vondo]

http://dive.scubadiving.com/html/200105buoyancycalc_chart.html

Since you know your weight for a 7 mil suit, you should be able to calculate the delta for fresh/salt and a shorty with pretty good accuracy.

 

[trucker girl]

What kind of water temps were you in for your OW dives? Were you comfortable in a 7 mil? I am always a little chilled when I dive in a 7 mil at Gilboa in Ohio- it's usually mid-70s above the thermocline... down to 55 degrees if you get down to 55 feet! I usually just stay above or at the thermocline.

I'm asking because I just got back from Oahu. I wore a 3 mil full for all my dives- except my twilight and night dives when I wore a 3 mil full plus a 3 mil shorty. For my day dives, I was always very chilled at the end of my 2nd dive. One deep, one shallow. For the night dive I was so cold that I really couldn't even enjoy the dive.

I think some of that was mental- how can I be only just a little chilled in Ohio in a 7 mil but be really cold in Hawaii on a night dive in warmer water than in Ohio (I assume- I never actually checked the water temp come to think of it)- I was wearing the equivalent of a 6 mil! Plus, I wore gloves and a beanie on all dives- not a full hood but a mil or so of protection on my head.

I figure that a lot of my chill on the night dive in Oahu was due to a cold surface interval- I just never warmed up.

You are entering paradise... just make sure you enter paradise prepared!

You may want to ask your Kauai diving question here: Scubaboard's Hawaii O'Hana Club

There are some really nice folks in that group.

BTW- cool chart, vondo.

 

[rakkis]

Were you wearing a one piece 7mm or a farmer john, two-piece 7mm? That makes a big difference.

 

[jon m]

wow, you were cold at 70F? we were diving in 57F to 60F... iwas wearing a one piece and the wife was in a farmer john.. only cold when we got out!
-me

 

[shakeybrainsurgeon]

You don't say who certified you... the PADI advanced open water text, in the peak performance buoyancy chapter, gives some rough algorithms for weighting. In a short wet suit, salt water, a good guess is 5% of your weight, about 12 pounds. You must take into account the tank (steel usually counts for 4 to 6 pounds, while aluminum requires the addition of at least 4 pounds to account for the negative buoyancy). In the end, these are just guesses...you will a) have to do a lot of buoyancy checks as you learn what weight each suit, tank and environment requires, and b) will need to use more weight early on (fear floats, so to speak --- the first few dives in a new environment will likely need more weight to get you under until you learn to relax and exhale completely). Good diving!

 

[trucker girl]

wow, you were cold at 70F? we were diving in 57F to 60F... iwas wearing a one piece and the wife was in a farmer john.. only cold when we got out!
-me

Did I forget to mention? I'm a serious wimp.

 

[scubasherry]

btw- any suggestions on a good dive for beginers in Kauii? don't really want to go deeper than 40-50'... thanks!!!!
-me

Make sure you talk to the dive opperation about what you want and let them know you are new divers. They can probably reccomend where they will take you as a novice diver and then you could do some research on those sites as well.

 

[spectrum]

Make sure you talk to the dive opperation about what you want and let them know you are new divers. They can probably reccomend where they will take you as a novice diver and then you could do some research on those sites as well.

I had a long disertation typed on a best guess weighting but there really are so many variables that it's hogwash.

I'll extend scubasherry's post to asking the operator about a weight suggestion. They will see you standing there (how you carry that 240 KB is a wildcard) , with the suit and cylinder dujour and should come darned close.

FWIW my guess is 10 pounds give or take 2. Have a great trip and be sure to report back with the result.

Pete

 

[Buoyant1]

I would just ask the dive operator to give you a little time to do a weight check before descending.

First dives in the ocean and salt water will probably have you end up a bit heavy at first, but if it's a several dive trip, you'll shed weight as the week goes on.

Have fun!