JJ Weight in the water (Warm Water)

Dave1w · September 1st, 2012, 02:40 AM

I'm just on my at back from Blue Marlin in Lombok, and was diving all week with a girl who was on a JJ.
I had a good look at it and do like it, but more importantly, she looked very comfortable in the water at almost any angle and position, almost like she was diving just a single.

My only concern with it would be how heavy or negative are they in the water with minimal wetsuit?

I'm diving my kiss now with ally cylinders, a flexible fabric/plastic backplate and no lead, and am just about right, but looking at the JJ, i think I'd end up with a fair bit of air in the wing. How do people find it in say a 3 mm wetsuit?
Dave

bazSXD · September 1st, 2012, 03:01 AM

Dave ... with a 3mm I would be amazed if you need any weight, ask Mat P he would be able to confirm this for you.

regards Baz

PS if your in Sydney in the near future come and take one for a spin .. !

Dave1w · September 1st, 2012, 03:56 AM

That's it, I'm worried about it being a little too negative, even given my natural bioprene!
I'm getting close to Sydney now, Jakarta isn't too far and I will drop by if I'm in town
Cheers
Dave

Tiptopperoo · September 2nd, 2012, 11:29 AM

Hey Dave (why are there so many bloody dives in the dive world??)

I did my MOD1 course in Thailand on the JJ in a mares 3mm with a scubapro2-3mm vest underneath. I had the standard unit with 3L steel tanks and standard steel plate.

I remember finding that although the unit was negative I was more concerned by it being a touch bum heavy. I wasn't carrying any any weight at all (I'm 75kg and pretty skinny). However lets bear in mind this was the first time I'd ever dived CCR. I did about 18 dives while I was over there and don't really think it was that much of an issue. I think I would try an ally plate and possibly ally tanks next time too. Tanks upright would help with the trim also.

It is awesome in a drysuit, and I think with a little tweaking it would be awesome in the tropics. I may just take a 5mm & hood next time I go!

Cheers,
Dave

packeteer · September 3rd, 2012, 09:34 AM

yes, for wetsuit diving, you really need to de-invert tanks and change to an alloy plate

ymmv, but it for me, it sorts out weight and trim issues

***tecdiverdude*** · September 4th, 2012, 11:50 AM

Well this I can speak about.
I am naturally negative. In fresh water in a used 5mm semi dei and fins.. That is all I have to keep a big breathe to stay afloat
In a single steel I use no weight

On JJ I de inverted for trim reasons and use al40s on board with ally plate and am just right in a 3mm

For a drysuit with moderate undergarment I use the staino plate..
Drysuit and URSUIT heavy undergarment I add 6lb

The unit can be adapted to suit your needs no matter the mission.

Venomguy · September 5th, 2012, 09:12 PM

Quote: (Originally Posted by Dave1w)

I'm just on my at back from Blue Marlin in Lombok, and was diving all week with a girl who was on a JJ.
I had a good look at it and do like it, but more importantly, she looked very comfortable in the water at almost any angle and position, almost like she was diving just a single.

My only concern with it would be how heavy or negative are they in the water with minimal wetsuit?

I'm diving my kiss now with ally cylinders, a flexible fabric/plastic backplate and no lead, and am just about right, but looking at the JJ, i think I'd end up with a fair bit of air in the wing. How do people find it in say a 3 mm wetsuit?
Dave

I have around 250 hours up now on the JJ in Tropical water, using 3mm and. 1mm suits. Have tried the JJ in most configs to get trim just right. The perfect trim for me has been the following,

Stardard Metal back plate,
Aluminium 2 L O2, as per normal config (valve down)
Offboard plugin Dil, 40 L Ali
Inserted water hose pipe 3/4 down the weight tubes and place 9cm of lead tube in the very top end of the tube,

Trim is sweet as

Drew

Don't be tempted to run with a Ali back plate or trains PAC , soft back pac etc as this does not spread the trim weight correctly.

Also make sure you set the backplate and lungs up on their best config settings for your body type, I find the top grommet hole for the plate and 2nd on the lungs gives best WOB and Trim for me

Dave1w · January 22nd, 2013, 03:54 AM

How have people found just changing to Ally tanks on it? I did a crossover at the weekend, and did find it a bit butt heavy, and overall quite negtive (buoyancy wise) but don't want right now to do much, except maybe change tanks. Luckily I have al 2 litre, al3 litre, al30, al40, steel 3s and 7s all available to try, but was wondering if I'll find a quick and easy solution going straight to the ally tanks

Cheers

Elmi · January 22nd, 2013, 04:17 AM

when i did my mod1 in safaga 2011 with Dave thompson he recommended using ali 3 liter with 3 mm wet-suit
diving here with 3mm i feel i am too heavy but do not find it a big deal diving with the standard rig that way.
do not want to hijack the thread , but going to dive with a 7mm wet-suit this weekend for first time so my question: do you need to add weight with 7mm or is it heavy enough.
diving from boat and no more time to check on a shore dive.
i know it is up to the individual but maybe somebody can give me an idea. Thanks
Cheers Elmi

divingtactics · January 22nd, 2013, 06:23 AM

I've dived mine valves down with 4 litre steel tanks, valves up with 3 litre steels, valves up with 40cuft allys and valves up with 7 litre steels and find it trims out well in all configurations - but I have always been in a drysuit with jetfins.

September 1st, 2012, 02:40 AM	#1
Dave1w Site Sponsor Join Date: Mar 2012 Location: Jakarta Posts: 145 Thanks: 1 Thanked 4 Times in 4 Posts	JJ Weight in the water (Warm Water) I'm just on my at back from Blue Marlin in Lombok, and was diving all week with a girl who was on a JJ. I had a good look at it and do like it, but more importantly, she looked very comfortable in the water at almost any angle and position, almost like she was diving just a single. My only concern with it would be how heavy or negative are they in the water with minimal wetsuit? I'm diving my kiss now with ally cylinders, a flexible fabric/plastic backplate and no lead, and am just about right, but looking at the JJ, i think I'd end up with a fair bit of air in the wing. How do people find it in say a 3 mm wetsuit? Dave
(Offline)

September 1st, 2012, 03:01 AM	#2 (permalink)
bazSXD New Member Join Date: Mar 2012 Location: Sydney Oz Posts: 62 Thanks: 1 Thanked 4 Times in 3 Posts	Dave ... with a 3mm I would be amazed if you need any weight, ask Mat P he would be able to confirm this for you. regards Baz PS if your in Sydney in the near future come and take one for a spin .. !
(Offline)

September 1st, 2012, 03:56 AM	#3 (permalink)
Dave1w Site Sponsor Join Date: Mar 2012 Location: Jakarta Posts: 145 Thanks: 1 Thanked 4 Times in 4 Posts	That's it, I'm worried about it being a little too negative, even given my natural bioprene! I'm getting close to Sydney now, Jakarta isn't too far and I will drop by if I'm in town Cheers Dave
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September 2nd, 2012, 11:29 AM	#4 (permalink)
Tiptopperoo CCRx Supporter Join Date: Mar 2012 Location: Melbourne Posts: 101 Thanks: 23 Thanked 10 Times in 7 Posts	Hey Dave (why are there so many bloody dives in the dive world??) I did my MOD1 course in Thailand on the JJ in a mares 3mm with a scubapro2-3mm vest underneath. I had the standard unit with 3L steel tanks and standard steel plate. I remember finding that although the unit was negative I was more concerned by it being a touch bum heavy. I wasn't carrying any any weight at all (I'm 75kg and pretty skinny). However lets bear in mind this was the first time I'd ever dived CCR. I did about 18 dives while I was over there and don't really think it was that much of an issue. I think I would try an ally plate and possibly ally tanks next time too. Tanks upright would help with the trim also. It is awesome in a drysuit, and I think with a little tweaking it would be awesome in the tropics. I may just take a 5mm & hood next time I go! Cheers, Dave Reason: spelling/grammar
(Offline)

September 3rd, 2012, 09:34 AM	#5 (permalink)
packeteer Big Member Join Date: Mar 2012 Location: Sydney, AU Posts: 68 Thanks: 1 Thanked 2 Times in 1 Post	yes, for wetsuit diving, you really need to de-invert tanks and change to an alloy plate ymmv, but it for me, it sorts out weight and trim issues
(Offline)

September 4th, 2012, 11:50 AM	#6 (permalink)
*tecdiverdude* Southern Moderation Join Date: Mar 2012 Location: Australia Posts: 428 Thanks: 66 Thanked 37 Times in 21 Posts	Well this I can speak about. I am naturally negative. In fresh water in a used 5mm semi dei and fins.. That is all I have to keep a big breathe to stay afloat In a single steel I use no weight On JJ I de inverted for trim reasons and use al40s on board with ally plate and am just right in a 3mm For a drysuit with moderate undergarment I use the staino plate.. Drysuit and URSUIT heavy undergarment I add 6lb The unit can be adapted to suit your needs no matter the mission. __________________ "DREAM as though you'll live forever LIVE as though you'll die tomorrow"
(Offline)

September 5th, 2012, 09:12 PM	#7 (permalink)
Venomguy New Member Join Date: Apr 2012 Location: PNG Posts: 32 Thanks: 0 Thanked 0 Times in 0 Posts	Quote: (Originally Posted by Dave1w) I'm just on my at back from Blue Marlin in Lombok, and was diving all week with a girl who was on a JJ. I had a good look at it and do like it, but more importantly, she looked very comfortable in the water at almost any angle and position, almost like she was diving just a single. My only concern with it would be how heavy or negative are they in the water with minimal wetsuit? I'm diving my kiss now with ally cylinders, a flexible fabric/plastic backplate and no lead, and am just about right, but looking at the JJ, i think I'd end up with a fair bit of air in the wing. How do people find it in say a 3 mm wetsuit? Dave I have around 250 hours up now on the JJ in Tropical water, using 3mm and. 1mm suits. Have tried the JJ in most configs to get trim just right. The perfect trim for me has been the following, Stardard Metal back plate, Aluminium 2 L O2, as per normal config (valve down) Offboard plugin Dil, 40 L Ali Inserted water hose pipe 3/4 down the weight tubes and place 9cm of lead tube in the very top end of the tube, Trim is sweet as Drew Don't be tempted to run with a Ali back plate or trains PAC , soft back pac etc as this does not spread the trim weight correctly. Also make sure you set the backplate and lungs up on their best config settings for your body type, I find the top grommet hole for the plate and 2nd on the lungs gives best WOB and Trim for me
(Offline)

January 22nd, 2013, 03:54 AM	#8 (permalink)
Dave1w Site Sponsor Join Date: Mar 2012 Location: Jakarta Posts: 145 Thanks: 1 Thanked 4 Times in 4 Posts	How have people found just changing to Ally tanks on it? I did a crossover at the weekend, and did find it a bit butt heavy, and overall quite negtive (buoyancy wise) but don't want right now to do much, except maybe change tanks. Luckily I have al 2 litre, al3 litre, al30, al40, steel 3s and 7s all available to try, but was wondering if I'll find a quick and easy solution going straight to the ally tanks Cheers
(Offline)

January 22nd, 2013, 04:17 AM	#9 (permalink)
Elmi New Member Join Date: Mar 2012 Location: Dubai Posts: 82 Thanks: 76 Thanked 8 Times in 6 Posts	when i did my mod1 in safaga 2011 with Dave thompson he recommended using ali 3 liter with 3 mm wet-suit diving here with 3mm i feel i am too heavy but do not find it a big deal diving with the standard rig that way. do not want to hijack the thread , but going to dive with a 7mm wet-suit this weekend for first time so my question: do you need to add weight with 7mm or is it heavy enough. diving from boat and no more time to check on a shore dive. i know it is up to the individual but maybe somebody can give me an idea. Thanks Cheers Elmi
(Offline)

January 22nd, 2013, 06:23 AM	#10 (permalink)
divingtactics Serious Swagelok Addict Join Date: Mar 2012 Location: Melbourne Australia Posts: 162 Thanks: 17 Thanked 18 Times in 17 Posts	I've dived mine valves down with 4 litre steel tanks, valves up with 3 litre steels, valves up with 40cuft allys and valves up with 7 litre steels and find it trims out well in all configurations - but I have always been in a drysuit with jetfins.
(Offline)