New BPW setup - worry about lift capacity?

Please register or login

Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

Benefits of registering include

  • Ability to post and comment on topics and discussions.
  • A Free photo gallery to share your dive photos with the world.
  • You can make this box go away

Joining is quick and easy. Log in or Register now!

That's smart. I'm not encouraging you to necessarily go deep, just that is where a potential issue may arise.
BTW, consider a rubber or (even better) a silicone freedive belt.. Super comfortable and stable.
I’m looking at one of the Mako ones - if the LDS doesn’t have what I need.
 
There is a nice article on selecting a wing at DGX.


That article focuses on drag and the taco effect, but another advantage of smaller wings is that in the event of a stuck inflator button, you are less buoyant while you sort out the problem.

Essentially, one should use the minimum wing size that is adequate, given the rest of the configuration.

On many of my single-tank recreational dives in Hawaii, assuming I'm with buddies (hence not slinging a pony), I use an Apeks 18lb wing, 6 lb steel backplate, 1 lb STA, AL80, no wetsuit, no lead weight anywhere, and I've never once filled the 18lb wing anywhere near full on an actual dive. When I use a wetsuit, I don't change the rest of the setup, but sometimes kick to get down. Unless there is a very strong current, I hold the safety stops neutrally buoyant, rather than using the line to control depth.

The following website has a specific guide to wing size:


Their statement of < 20 lbs as a guideline for tropical diving with a single AL80 is consistent with my experience. They also recommend 30 lbs for cold-water diving with a steel cylinder which I recognize may be closer to the OP's typical setup, but most divers eventually spend at least some of their time in tropical water.
 
don't be afraid to swim down from the surface. Initial descent is always a little harder.
I've not found swimming down to be necessary when properly weighted. With a 3mm, I'm neutral with an empty wing at the safety stop with tank at reserve level, so on the surface I'd be 2.5 lb positive (from suit expansion). With a 7mm, I weight myself to be 2.5 lbs positive on the surface as well. (Weighting for neutral at 15 ft would make me close to 5 lb positive on the surface which isn't conducive to a controlled ascent in the last 5 ft or so.) Either way, at the beginning of the dive with the additional weight of the air I haven't yet breathed on my back, I'm negatively buoyant with an empty wing (by about 2.5-3 lbs). As long as I don't kick and I exhale normally, I am definitely going down when I vent the wing.
 
  • Like
Reactions: L13
I’m looking at one of the Mako ones - if the LDS doesn’t have what I need.
I find the Mako ones to be very good, and have not seen a comparable product at local dive shops in the area. Most of the ones here sell a nylon belt with a buckle and pockets for weight. I hate those things. I love my rubber Mako belt. They also make silicone ones which come in fun colors, and are a little stretchier. Also a good product, but at the end of the day I prefer the rubber overall.
 
I find the Mako ones to be very good, and have not seen a comparable product at local dive shops in the area. Most of the ones here sell a nylon belt with a buckle and pockets for weight. I hate those things. I love my rubber Mako belt. They also make silicone ones which come in fun colors, and are a little stretchier. Also a good product, but at the end of the day I prefer the rubber overall.
Brett, I know this is a little off topic, so feel free to DM me with the answer, if you’re ok with that. I use a rubber belt but was considering a silicone. Why do you like the rubber better?

Thanks,
Erik
 
Just a plug for a RESOURCE here on the board. Check out The Optimal Buoyancy Computer. It can be a little tedious to get all the information and set it up, but once you go through it you'll have a very good understanding of what you need and what effects changing gear will have. I switch between two sets of doubles, an AL80, a dry suit, a 3mm wetsuit and fresh and salt water and the calculator generally gets me within about 2lbs. It can also show you the amount of lift you need and where you might want to put weights....
 
There is a nice article on selecting a wing at DGX.


That article focuses on drag and the taco effect, but another advantage of smaller wings is that in the event of a stuck inflator button, you are less buoyant while you sort out the problem.

Essentially, one should use the minimum wing size that is adequate, given the rest of the configuration.

On many of my single-tank recreational dives in Hawaii, assuming I'm with buddies (hence not slinging a pony), I use an Apeks 18lb wing, 6 lb steel backplate, 1 lb STA, AL80, no wetsuit, no lead weight anywhere, and I've never once filled the 18lb wing anywhere near full on an actual dive. When I use a wetsuit, I don't change the rest of the setup, but sometimes kick to get down. Unless there is a very strong current, I hold the safety stops neutrally buoyant, rather than using the line to control depth.

The following website has a specific guide to wing size:


Their statement of < 20 lbs as a guideline for tropical diving with a single AL80 is consistent with my experience. They also recommend 30 lbs for cold-water diving with a steel cylinder which I recognize may be closer to the OP's typical setup, but most divers eventually spend at least some of their time in tropical water.
Just read both the articles. I was using Optimal Buoyancy Computer and it recommended to move any non-trim weight to my body since it said my rig is too heavy when I ran the numbers. But…

One often hears justification for needing excess lift is because the diver carries a very large amount of lead weight to counter the buoyancy of their thick wetsuit or drysuit and needs the excess lift capacity "just in case." The solution is not to have an oversized wing to counter the weight, but rather, to configure the lead so it can be incrementally dropped in an emergency. Yes, we acknowledge there are special circumstances in extreme technical diving that require enormous excess lift capacity, but these are pretty rare. In general, lift capacity when choosing a wing is a minor consideration.
Looks like I’ll also be fine using droppable weight pockets on my waist webbing and I can drop my weight in an emergency and really need to do an a buoyant ascent. I don’t plan on finding myself in “extreme”, techy dives beyond my current and planned certs. I’ve been diving with a thick wetsuit and a rental BPW for the last 3 dives - so far, I’ve found myself in control of my buoyancy underwater, no major changes from a “hybrid” BCD(Hydros Pro).
 
Just read both the articles. I was using Optimal Buoyancy Computer and it recommended to move any non-trim weight to my body since it said my rig is too heavy when I ran the numbers. But…


Looks like I’ll also be fine using droppable weight pockets on my waist webbing and I can drop my weight in an emergency and really need to do an a buoyant ascent. I don’t plan on finding myself in “extreme”, techy dives beyond my current and planned certs. I’ve been diving with a thick wetsuit and a rental BPW for the last 3 dives - so far, I’ve found myself in control of my buoyancy underwater, no major changes from a “hybrid” BPW.

A buoyant ascent is, by all accounts, extremely dangerous, and should be avoided.

Suppose that a single-tank recreation diver in a wetsuit is configured in such a way that they can hold a safety stop with an empty wing and low tank pressure, neutrally buoyant. That should also imply that they can kick their way up to the safety stop from standard recreational depth of < 100ft with an empty wing, and also that they will be slightly positive at the surface. Then, in what situation exactly, is that diver supposedly needing to remove and drop lead weight? Essentially, the buoyancy provided by the wing in this configuration is quite useful during the dive, but not actually necessary to save your life, and moreover, quickly becoming super-buoyant by removing an entire weight belt sounds super-dangerous.

If I were planning to use lead weight for some reason, and I were going on a dive boat, weight pockets are quite convenient, because I can leave my weights at home, bring a lighter bag to the boat and then quickly add the boat's lead to my rig, NOT because I want to potentially empty the pocket of its contents.
 
Essentially, one should use the minimum wing size that is adequate, given the rest of the configuration.
I disagree with this statement. A wing is advertised with 30lbs of lift, what exactly does that mean? Is that in freshwater or saltwater? How was lift measured? Did they add weight to a naked wing until it sinks and call it a day? or Did they measure it with a plate attached? This is important because a plate can restrict a wing from inflating fully. So your wing may have less lift than you think. There are past threads about this.

Also what about when configurations change? I lived in Miami, in the summer you can dive with nothing more than a rash guard. If you go deeper maybe a 3mm. In winter you need a 3mm and some people who are sensitive to the cold use a 5mm. There was a recent thread where the poster wished he bought a bigger wing because he got into photography needed more lift because of the camera. What if a diver decides he wants to go lobstering or treasure hunting? or go solo and carry a pony?

I never understood the minimum wing philosophy. There is not much difference in size between a 20lb wing and a 30lb wing so drag is not a problem. The DGX article may have been true 20 years ago when large wings were in style, especially when people were using doubles wings with a single tank. However when narrow wings came out the main difference in size was the length not the width so "tacoing" is not a problem. The Andy Davis recommendation for a 20lb wing for tropical diving is fine, but he lives in a true tropical location where I suspect the water temps don't vary as much as in other locations.
 
I disagree with this statement. A wing is advertised with 30lbs of lift, what exactly does that mean? Is that in freshwater or saltwater? How was lift measured? Did they add weight to a naked wing until it sinks and call it a day? or Did they measure it with a plate attached? This is important because a plate can restrict a wing from inflating fully. So your wing may have less lift than you think. There are past threads about this.

Also what about when configurations change? I lived in Miami, in the summer you can dive with nothing more than a rash guard. If you go deeper maybe a 3mm. In winter you need a 3mm and some people who are sensitive to the cold use a 5mm. There was a recent thread where the poster wished he bought a bigger wing because he got into photography needed more lift because of the camera. What if a diver decides he wants to go lobstering or treasure hunting? or go solo and carry a pony?

I never understood the minimum wing philosophy. There is not much difference in size between a 20lb wing and a 30lb wing so drag is not a problem. The DGX article may have been true 20 years ago when large wings were in style, especially when people were using doubles wings with a single tank. However when narrow wings came out the main difference in size was the length not the width so "tacoing" is not a problem. The Andy Davis recommendation for a 20lb wing for tropical diving is fine, but he lives in a true tropical location where I suspect the water temps don't vary as much as in other locations.


Just as you have different size spanners in a toolbox, I am an advocate of selecting the right tool for the job on the day. I think at the start of the dive, you will know whether or not it is tropical -- select the 20 lb wing from your toolbox, as it is the right tool for that dive. However, yes I grant that most divers will be unable to tell the difference between a 20lb wing and 30lb because the difference in drag is not their main problem. If your trim is perfect then the drag of other components in your kit becomes noticeable. If you will only ever buy one wing in your life and you will travel around with it, then definitely the 30lb can be adapted to more scenarios than the 20lb.
 

Back
Top Bottom