Reassurance Requested

[Streydog]

So I purchased an AL BP and a 20lb wing so that I will be able to travel with only carry on luggage. I have been using a Zeagle Brigade that has a 34lb wing. I have a trip coming up next week and I am questioning my decision on the wing size.

With my Brigade, using the same 2.5mm suite I plan on using next week, I use no extra weight using a 120 HP steel tank and I use around 8lbs of lead with an AL 80. I will be using 120 HP steel tanks on this trip.

I know there are quite a few discussions on wing size on this board, I have read many of them. One comment I see often is that you need a larger wing if you are using 120's. Am I wrong in thinking that besides ditchable weights there would not be any difference in diving an AL 80 with an extra 8lbs of lead?

 

[runsongas]

You will be slightly overweighted with the AL BP if you currently use no weight with the brigade. Worst case with a full 120 is you will be roughly around 14 to 15 pounds negative with a wing failure at depth right at the beginning. If you are a good swimmer, that is manageable. a lift bag or large dsmb for some redundancy in case is not a bad idea though.

The difference with the AL80 is that it gives you ditchable ballast so that with a wing failure, you can drop some weights to swim up easier.

 

[dmaziuk]

I think if you plan for total wing failure you should carry a redundant lift source (buddy?) with either 20 or 34 lb wing. Whereas a not failing 20 lb wind should work fine.

 

[Scared Silly]

You use no extra weight with a HP 120 when it is empty so that is 9lbs of ballast from the cylinder. Your Brigade was probably 3-4 lbs positive. So at the start of the dive you are 5-6 lbs. negative at the surface.

Now you swap out the Brigade with an aluminum BP that is around 3 lbs negative. So now you are 12lbs negative at the surface.

Once at depth your 2.5 mil suit has zero buoyancy. So you lose a couple more pounds of buoyancy. So now you are around 14-15lbs negatively buoyancy. (That is similar to runsongas number).

Will your 20lb wing hold 15lbs when matched with the HP120. Probably close to that. If you really want to know head to your pool and try it.

But as said can you swim that 14-15lbs up if you had a total wing failure? Can you hold it at the surface?

FWIW we use ~30lb wings for our singles diving with about 4-6 lbs of detachable weight with an AL80.

 

[RayfromTX]

The benefit to using a 20 is that you will be using a higher percentage of the wing which is nice for how it handles when you need about 7 lbs of lift. The downside is that you will be using a higher percentage of your wing capacity so there may be a situation where a critical event would beg for a bit more lift. I don't have enough experience to say "I once had to help a diver with a failed wing and this and this and this all happened at the same time and I'm sure glad I had an extra 14 pounds of lift that I had never really needed before. I think dive masters often carry extra weight and extra lift so they can get others out of a bind but I don't see myself being in that position and I carry an smb on every dive so there is a bit of lift.

I have seen this debated several times here but the one point that I haven't seen raised is if you have a runaway inflater valve. I would rather it be inflating a 20 than a 34 if a 20 is all I really need.

I use a 20 with a 3 mil suit in salt water with an AL80 and I carry 6 pounds of lead with a kydex plate. It is plenty at the surface. It is more than plenty at depth.

At home in fresh water with the same plate I use no weight with a steel 100 and a five mil suit and it is a bit overweighted to the point that at the surface with a full tank I am not riding very high in the water and choppy waves are a bit of a drag(not terrible). At the bottom it is a fairly full wing. I have opted to get a used 26 lb wing when one came up for sale. I haven't dived it yet but I think it will be more optimal and certainly it will if I dive a three mil suit.

I predict you will be ok with your 20 and the steel 120. Easy enough to see what it has at the surface with a full tank. Just put it on after you get in and see how you like it's float. It's only going to get better as you drain the tank.

Having said all that there seem to be two schools of thought about wing size and cutting it close. Tobin doesn't recommend more lift than is needed to float the rig at the surface with a full tank or compensate for a compressed suit at depth. Others such as the chairman see no reason to cut it close and will dive 15 lbs or so more than that. I fall in Tobin's camp. With my 26 lb wing at home I'm striking in the middle even though I've done several deep dives with some reserve capacity with my 20lb wing. I really think as long as the rig is balanced and you have enough capacity to meet Tobin's guidelines (not that he invented them), The rest comes down to how much lift it takes to be comfortable at the surface in choppy water while you wait for the boat. We had a norte this week and at the surface I kept my reg in my mouth. There is more than the 6 lbs I carry in difference between an AL80 and a steel 120 but not a huge amount more. If I was going to dive the 120s a lot I would go to a 26 lb wing or thereabouts.

 

[Streydog]

Thanks for everyone's input. I am not going to be able to get to a pool before I leave. My first two days I will be using AL 80's then 5 days of 120's. I might drag my Brigade down this trip just a security blanket this time.

 

[uncfnp]

I am not good at math but have experience with both al and steel tanks plus owning both 18 and 30 wings I will say that my personal preference would be a 30 wing with steel 120’s. The 20 wing will not be much support at the surface if you need to spend much time waiting on a boat.

If you have the funds I would order, overnight or 2 day, a 30 wing.

However, you are diving with Aldora so will always be with a group so if any issues you should have plenty of nearby support. And if you find you are not comfortable with the 20 you could rent a BCD or possibly buy/borrow a larger wing for your trip.

 

[AdivingBel]

I've dived both 20 & 32 lb wings for warm water, tropical diving and haven't had wing related issues with either. For me diving "heavier" tanks is getting used to the different weight distributions and possibly having to dive a bit heavy (I use 6 lbs with an AL80) due to adding trim weights in order to compensate for all the weight high on my back. That causes me to run a bit more air in my wing to get neutral and the extra "niggles" that involves, but it's all easily doable if that's the tanks your diving. None of these issues are wing size related to any realistic degree. As far as on the surface, both of my rigs were back inflate, so I used as little air a possible in the wing and laid back while waiting to reboard. I don't think I've ever fully inflated my wing on the surface. I guess if you were abandoned on the water, a bigger wing that might sit you higher would be a benefit, but at that point you've got bigger problems. I wouldn't worry and go have fun. As @uncfnp said, when you get there if something doesn't work for you, rent. Your op or another op will have plenty of gear that will work. All IMHO, YMMV.

 

[Jayfarmlaw]

Streydog, I had no problems with an aluminum Backplate and 23# tropical wing. I think I was just diving a skin on that trip as well, no 3mil full suit. I was in the same situation as you and shot Dave an email just for reassurance. Welcome to the dark side of the BPW family!

Safe travels,
Jay

 

[RyanT]

The amount of lift in your wing is irrelevant if you are planning for a catastrophic failure. If you had a 500lb wing that wouldn't hold air, it doesn't matter. A steel 120 will be around 9 lbs negative at the start of the dive. The BP will be around negative 2. Maybe a couple more lbs of additional gear will bring you to around -14 lbs at the start of the dive. Once you add in a few pounds of buoyancy for your wetsuit and your 20 lb wing should have no trouble lifting you in the rig. In the event of a catastrophic wing failure, something like a decent smb would be a good idea for surface buoyancy, otherwise, your wing should be fine for the dives.