Calculating whether 30# lift is enough in a wing

[anth]

BigTuna,

I've had a 30lb wing with a ss plate for about a year now. Since then, it has been with me on well over a hundred dives in New England with a 7mm farmer john. I was really concerned that 30 lbs lift would not be enough, but it is a thing of beauty, it's plenty. A few weeks ago, I took it to Belize and dove it with a 3mm suit, and it was great there. I am a smaller guy, somewhere around 140 lbs and wearing around 16 lbs of lead with my 7mm, so your mileage may vary. See if you can borrow a wing and try it out.

I'm very familiar with the compression of suits at depth, but I figure your 2/3 loss of bouyancy at 66 feet might be a little conservative, as I imagine that Boyle's Law isn't perfectly applicable. The individual nitrogen-filled cells in the neoprene must have a little bit of rigidity anyway, right?

The big thing that you have overlooked is your DIVE BUDDY. What happens if he/she gets in trouble and needs you help? When buying a BC the first thing I tell people to look at is the lift. You can never have too much lift. What happens if your buddy is tired or stressed on the surface and has to hand you their 20# weight belt? If you only have a 30# lift then all of a sudden you are 15 or so pounds neg..... I know you could always drop the belt but.... You need to build in extra for emergency's!

In reference to the aforementioned rescue value of a huge wing with a giant lift capacity, that's not what I learned in my rescue training. If my buddy is tired or stressed and needs to ditch their weights on the surface, I'm going to be busy helping them, not trying to hold onto a few bucks worth of lead. Additionally, correct-sized wings remove some of the temptation to use a BC as a lift bag.

You're on the right track, BigTuna! Good luck!

-Anthony

 

[SangP]

Hi divecon15,

Thanks for your input however, I was always taught to bring along a smb or something similar. In fact I try... try to carry around my 6 foot halcyon dive alert whenever I can... try is the operative word.

As for my buddy needing 20 lbs... I don't have abuddy who needs #20 in fact I try to stay away from pp whose bcs are so badly overweight that weights have created permanent shapes in the bc pockets... eg nearly dead velcro, pregnant looking BCs and other obvious signs.

Use gear that's appropriate for the situation. Tropical gear... at most 10lbs in weight. Dry suit maybe another 4 at most? Seriously, having the correct design in the wing and you are less likely to encounter any problems.

Oxycheq is #30 but more like #32 as most of the wing is underwater unlike my Halcyon although I like the pillow effect of my wing as I can lean back and just
r e l a x... snore....

30 is really more than enough... trust me. Even with a single steel tank and a steel plate... more than enough.

SangP

 

[JimC]

What happens if your buddy is tired or stressed on the surface and has to hand you their 20# weight belt? If you only have a 30# lift then all of a sudden you are 15 or so pounds neg..... I know you could always drop the belt but.... You need to build in extra for emergency's!

I drop it. LOL

Unless your doing something weird, or have a body that is a ways outside "normal" 30# of lift is MORE than enough for single tank diving. Heck, I could do 90% of my double tank diving with a 30# lift wing.

 

[Wristshot]

Hi,

First off you won't need 20lbs if you are diving wet and are using a al tank. At most you would need 8-10lbs.
Here in the tropics some of the guys don't even need weights to go under when using a bp/w rig and the plate is al not steel like what you are looking to get. For me I only need 6-8 on the first dive to wet the wetsuit and on the next dives I can get away with 2-4 lbs only.

30 lbs is more than enough if you are doing a single tank config and in fact a certain DIR instructor in Singapore only uses 40lbs for his doubles config.

Try not to over calculate everything and just borrow/rent a bp/w to test.

Everything will explain itself once you are in the water in this rig.

Cheers,

SangP

First off, let me say that this is not meant as a personal attack on you SangP.

He said that it was a 7/5 wetsuit. Diving cold in my area in a 7mm wetsuit very often means more than 20 lbs of lead required wil AL80. I don't know of many people around here that can get away with 8-10 lbs. He did not specify where he plans to dive, but the wetsuit thickness controls the bouyancy, not the location.

Of course remember also that ITS NOT A COMPETITION. Every diver should use whatever they need to use and not get hung up on the number. While it is good for each diver to work on their skills, trim etc to minimize the amount needed, no reasonable amount is "wrong".

Remember that his question was not "how much weight should I wear" but whether a 30# wing would be adequate, and whether there were errors in his logic.

Big Tuna,

As far as the follow on question about swimming up 6 lbs: you would probably be surprised how easy that would be once you get comfortable. When a diver dropped a weight pouch inside a wreck, I was able to pick it up and carry it to him with no special actions required. I just breathed a little deeper for a little while to counter the extra weight I was carrying.


Wristshot

 

[SangP]

First off, let me say that this is not meant as a personal attack on you SangP.
He said that it was a 7/5 wetsuit. Diving cold in my area in a 7mm wetsuit very often means more than 20 lbs of lead required wil AL80. I don't know of many people around here that can get away with 8-10 lbs. He did not specify where he plans to dive, but the wetsuit thickness controls the bouyancy, not the location.
Of course remember also that ITS NOT A COMPETITION. Every diver should use whatever they need to use and not get hung up on the number. While it is good for each diver to work on their skills, trim etc to minimize the amount needed, no reasonable amount is wrong".
Remember that his question was not "how much weight should I wear" but whether a 30# wing would be adequate, and whether there were errors in his logic.
Wristshot

Hi Wristshot,

Man you are so polite and I completely understand that it's your right to disagree with my views and I'll submit to your better judegement and experience as I'm a warm water diver and the only time time I tried anything like it was in perth in a 5mm hooded freediving suit... I needed 12lbs then.

As for the needing any more than 30# lift I based my explanation on why he would need 20# lbs in the first place.

All said, I've seen a local diver with these gear on a dive
Halcyon HID lamp, underwater scooter, hooded 3 mm suit, DSLR camers and lighting. The guy looked like a walking BUG and he was using a #30 wing.

Btw, Wristshot may I ask for your singles rig in a 7/5 wetsuit, what wing do you use?

Bigtuna, if you are really worried about lift you could try the Oxycheq 40 or the Golem 35. They don't look any bigger than my Halcyon 30.

Best regards,

SangP

 

[BigTuna]

Bigtuna, if you are really worried about lift you could try the Oxycheq 40 or the Golem 35. They don't look any bigger than my Halcyon 30.

SangP, thanks to your input and that of most others, plus respondents' basic confirmation of my understanding about how positive and negative buoyancy sources play together, I'm convinced that 30# will be fine for me.

This has been an extremely informative thread for me. Thanks, everybody!

 

[kidspot]

Just to "stir thing up" a bit.... I dive a 30# Pioneer, wear 24# total weight (including bp) in my DS here in the "subtropics" (about the same as if I were wearing a 5mil suit)

Back when I was wearing a 3mil full suit I had a buddy drop a weight belt while we were at the surface... He couldn't get it, so I went for it... (I know a lift bag *should* be used for lifting objects) I picked it up and started swimming up... but didn't get far... inflated my wing all the way... still negative... but I was able to swim it up at that point.

That said... I'd still go with a 30# wing If you feel you need more Halcyon does make a 36# wing also... But I really like the streamlined nature of the 30 over the 36.

One other thing to consider in favor of a smaller wing. In the event of a lp inflator malfunction... would you rather have the possibility of 30 or 50 lbs dragging you toward the surface before you disconnected and got the excess vented?

Just some more "opinion" to consider - Have fun shopping

Aloha, Tim

 

[SangP]

Thanks Bigtuna and the rest of the guys for your input.

Please, please bring along an smb just in case Bigtuna as I'm not too familiar with the type of diving you do. Jagfish was selling some carter SMBs and it would do you no harm to pm him to ask about some smbs in case there is any lifting problems with your wing.

Cheers and best wishes.

SangP

 

[BigTuna]

Please, please bring along an smb just in case Bigtuna as I'm not too familiar with the type of diving you do. Jagfish was selling some carter SMBs and it would do you no harm to pm him to ask about some smbs in case there is any lifting problems with your wing.

I always carry a SMB and spool. Standard equipment.