Am I doing this right?

Leg of Salmon · November 21st, 2008, 09:38 AM

First time in the pool last night since GUE-f and I did a weight check.

I was in full cold weather gear, hood, gloves, base layer, socks, Santi 400. I didn't have any backup torches or other stuff but did have my primary light, (Pro3). Tanks down to 30bar, wing sucked empty, drysuit squeezed tight, fins still and had to add 3 kilos to sink down.

My BP is 4.4kg and my tanks are 14kg ECS.

I think I would have to add another 4 kilos for salt water. This would be 7kg in total with heavy cylinders and BP.

Does this seem like too much in your experience? Too little.

I know everyone needs but they need but would just like to hear your thoughs

Love in a bun dance
Chris

**jb2cool** · November 21st, 2008, 09:51 AM

I'd have thought that adding 4Kg for salt might be a touch too much. I tend to have to add 2Kg for the move between fresh and salt.

GLOC · November 21st, 2008, 10:08 AM

Yep, I add 2kg from fresh to salt and seems to work out okay.

Leg of Salmon · November 21st, 2008, 10:16 AM

Nice one, I will give that a go.

5kg in salt
4.4kg BP
2x12l 14kg ECS

*Brian Allen* · November 21st, 2008, 10:27 AM

I find that 2.5 - 3% of your total mass when neutral is generally what is required when moving from salt to fresh or vice versa. This will vary according to temp / salinity around the world but not by that much ;-)

Re your weighting remember that your breathing makes a big difference - up to 6 kg, and that the weight check is supposed to be at 3m. If you have near empty tanks at the surface you definitely should not be able to sink if you have just breathed in.

Good luck

B

Leg of Salmon · November 21st, 2008, 10:29 AM

Quote: (Originally Posted by Brian Allen)

I find that 2.5 - 3% of your total mass when neutral is generally what is required when moving from salt to fresh or vice versa. This will vary according to temp / salinity around the world but not by that much ;-)

Re your weighting remember that your breathing makes a big difference - up to 6 kg, and that the weight check is supposed to be at 3m. If you have near empty tanks at the surface you definitely should not be able to sink if you have just breathed in.

Good luck

B

Yep. I breathed out hard on the surface and started to sink.

Paul Burgess · November 21st, 2008, 10:49 AM

Difficult to do in a pool, but a weight check is best done coming up to a stop depth rather than going down from the surface (ie go down to 5m, take squeeze of the suit and then come up to hold a stop at 3m).

This is because going straight down to 3m, your suit may be squeezed a lot more than would normally be the case on an ascent where your dump valve is doing the work.

Paul

NickB · November 21st, 2008, 01:08 PM

What Paul said.

With near-empty cylinders, I wouldn't expect to start descending without having to do a bit of a duck dive to get going. You'll have pockets of trapped air that will have been squeezed out after being at depth.

I'll bet you could take another kilo off easily

And +2kg for the sea like everyone else.

Gav · November 21st, 2008, 01:14 PM

Quote: (Originally Posted by Paul Burgess)

Difficult to do in a pool, but a weight check is best done coming up to a stop depth rather than going down from the surface (ie go down to 5m, take squeeze of the suit and then come up to hold a stop at 3m).

This is because going straight down to 3m, your suit may be squeezed a lot more than would normally be the case on an ascent where your dump valve is doing the work.

Paul

Same person did your weight check as did mine

Leg of Salmon · November 21st, 2008, 01:23 PM

Quote: (Originally Posted by NickB)

What Paul said.

With near-empty cylinders, I wouldn't expect to start descending without having to do a bit of a duck dive to get going. You'll have pockets of trapped air that will have been squeezed out after being at depth.

I'll bet you could take another kilo off easily

And +2kg for the sea like everyone else.

Ok, I will give it a go. I hope I dont end up looking like a prat though!

November 21st, 2008, 09:51 AM	#2 (permalink)
jb2cool (Online) Padawan learner Join Date: Nov 2005 Location: Bracknell, Berkshire Posts: 804	I'd have thought that adding 4Kg for salt might be a touch too much. I tend to have to add 2Kg for the move between fresh and salt. __________________ http://jb2cool.bulldoghome.com

November 21st, 2008, 10:08 AM	#3 (permalink)
GLOC(Offline) Moderator Join Date: Nov 2005 Location: Fleet, Hants Posts: 2,068	Yep, I add 2kg from fresh to salt and seems to work out okay. __________________ Gareth Images of Life Photography DIR Team Foxturd Travels Underwater and Further Afar If you don't have the time to do something right, where are you going to find the time to fix it? - Stephen King

November 21st, 2008, 10:27 AM	#5 (permalink)
Brian Allen(Offline) GUE Instructor Join Date: Nov 2005 Location: London & Plymouth Posts: 594	I find that 2.5 - 3% of your total mass when neutral is generally what is required when moving from salt to fresh or vice versa. This will vary according to temp / salinity around the world but not by that much ;-) Re your weighting remember that your breathing makes a big difference - up to 6 kg, and that the weight check is supposed to be at 3m. If you have near empty tanks at the surface you definitely should not be able to sink if you have just breathed in. Good luck B __________________ ...dive planning again ... GUE fundamentals and Halcyon Equipment Online www.ocean-explorers.co.uk

November 21st, 2008, 09:38 AM	#1 (permalink)
Leg of Salmon(Offline) New Member Join Date: Dec 2007 Location: Belfast Posts: 154	First time in the pool last night since GUE-f and I did a weight check. I was in full cold weather gear, hood, gloves, base layer, socks, Santi 400. I didn't have any backup torches or other stuff but did have my primary light, (Pro3). Tanks down to 30bar, wing sucked empty, drysuit squeezed tight, fins still and had to add 3 kilos to sink down. My BP is 4.4kg and my tanks are 14kg ECS. I think I would have to add another 4 kilos for salt water. This would be 7kg in total with heavy cylinders and BP. Does this seem like too much in your experience? Too little. I know everyone needs but they need but would just like to hear your thoughs Love in a bun dance Chris

November 21st, 2008, 10:16 AM	#4 (permalink)
Leg of Salmon(Offline) New Member Join Date: Dec 2007 Location: Belfast Posts: 154	Nice one, I will give that a go. 5kg in salt 4.4kg BP 2x12l 14kg ECS

November 21st, 2008, 10:29 AM	#6 (permalink)
Leg of Salmon(Offline) New Member Join Date: Dec 2007 Location: Belfast Posts: 154	Quote: (Originally Posted by Brian Allen) I find that 2.5 - 3% of your total mass when neutral is generally what is required when moving from salt to fresh or vice versa. This will vary according to temp / salinity around the world but not by that much ;-) Re your weighting remember that your breathing makes a big difference - up to 6 kg, and that the weight check is supposed to be at 3m. If you have near empty tanks at the surface you definitely should not be able to sink if you have just breathed in. Good luck B Yep. I breathed out hard on the surface and started to sink.

November 21st, 2008, 10:49 AM	#7 (permalink)
Paul Burgess(Offline) New Member Join Date: Jun 2008 Location: Surrey Posts: 13	Difficult to do in a pool, but a weight check is best done coming up to a stop depth rather than going down from the surface (ie go down to 5m, take squeeze of the suit and then come up to hold a stop at 3m). This is because going straight down to 3m, your suit may be squeezed a lot more than would normally be the case on an ascent where your dump valve is doing the work. Paul

November 21st, 2008, 01:08 PM	#8 (permalink)
NickB(Offline) Always lowering the tone Join Date: Dec 2005 Location: Cardiff, UK Posts: 364	What Paul said. With near-empty cylinders, I wouldn't expect to start descending without having to do a bit of a duck dive to get going. You'll have pockets of trapped air that will have been squeezed out after being at depth. I'll bet you could take another kilo off easily And +2kg for the sea like everyone else.

November 21st, 2008, 01:14 PM	#9 (permalink)
Gav(Offline) New Member Join Date: Jan 2007 Location: UK Posts: 110	Quote: (Originally Posted by Paul Burgess) Difficult to do in a pool, but a weight check is best done coming up to a stop depth rather than going down from the surface (ie go down to 5m, take squeeze of the suit and then come up to hold a stop at 3m). This is because going straight down to 3m, your suit may be squeezed a lot more than would normally be the case on an ascent where your dump valve is doing the work. Paul Same person did your weight check as did mine

November 21st, 2008, 01:23 PM	#10 (permalink)
Leg of Salmon(Offline) New Member Join Date: Dec 2007 Location: Belfast Posts: 154	Quote: (Originally Posted by NickB) What Paul said. With near-empty cylinders, I wouldn't expect to start descending without having to do a bit of a duck dive to get going. You'll have pockets of trapped air that will have been squeezed out after being at depth. I'll bet you could take another kilo off easily And +2kg for the sea like everyone else. Ok, I will give it a go. I hope I dont end up looking like a prat though!