New Diver - Advice on Purchasing Zeagle Express Tech BC

[Brewski]

On a separate note, Rick STILL doesn't have his captain's ticket, so you should address him as "hey swaby"

Roger that Capn!

 

[Bubbletrubble]

Unless you have a neoprene drysuit (or possibly a full compressed neoprene suit), your suit will almost certainly sink when completely saturated. I know my CLX50/50 will and it is 1/2 compressed neoprene. Try it if you don't believe me. The next time your suit gets a little funky and needs the inside rinsed out, fill it up and toss it in a pool. The trilam suits aren't too heavy, but the rubber Viking suits with integrated boots will go down like a big chunk of rubber. (because, well, that's what it is, and rubber sinks) Don't count on much flotation from your insulation either. When in doubt test it for yourself, an assumption could prove quite costly.

Trying to float the drysuit + undergarments in a pool isn't exactly a fair test of buoyancy. I dive in salt water after all.

I don't have any experience using thick rubber drysuits with attached boots (Viking commercial suits?). Are the boots composed of material so negatively buoyant that they would drag down the rest of the suit? Is the suit material itself negatively buoyant? I have no idea. I have a bilaminate suit with neoprene booties and rockboots. I'm fairly certain that the suit and my undergarment (fully flooded) are not negatively buoyant. Water inside the suit will be neutrally buoyant relative to the water outside the suit. A water-logged undergarment will definitely lose its positive buoyancy, but I don't think it will become negatively buoyant. I'll concede that the material composing the drysuit could be a different matter, however.

Even with a catastrophic flood, it's hard for me to imagine my drysuit + undergarments being so negatively buoyant that the positive buoyancy of air in my lungs would not make me at least neutrally buoyant. Do you mind if I open this issue up to the ScubaBoard community? I'd like to start a new thread on the topic. I feel bad about hijacking the thread like this.

 

[Jon Nellis]

Do you mind if I open this issue up to the ScubaBoard community? I'd like to start a new thread on the topic. I feel bad about hijacking the thread like this.

Don't have to ask my permission, but I have a feeling what you'll get is a whole lot of comparisons of numerous drysuit/undergarment combinations followed by folks adding in how much crap they have stuffed in their leg pockets, neoprene boot vs rock boot weight comparisons and whether or not to include negatively buoyant vs positively buoyant fins as part of the drysuit since they have not yet been accounted for yet in the other gear weight. I predict 10 pages of discussion with the ultimate conclusion being "It depends"

As for the hijack, the thread about advice on purchasing a Zeagle ET was pretty much over when the OP bought a different BC.

Here's a link to a wing buoyancy calculator on the board http://www.scubaboard.com/forums/bu...ems/158370-ultimate-wing-lift-calculator.html or you could give Tobin at DSS a call and let him recommend a wing. I'm willing to bet he recommends at least a 35lb wing, maybe even a 40lb for your setup.

Signing off,
Jon

 

[Bubbletrubble]

Don't have to ask my permission, but I have a feeling what you'll get is a whole lot of comparisons of numerous drysuit/undergarment combinations followed by folks adding in how much crap they have stuffed in their leg pockets, neoprene boot vs rock boot weight comparisons and whether or not to include negatively buoyant vs positively buoyant fins as part of the drysuit since they have not yet been accounted for yet in the other gear weight. I predict 10 pages of discussion with the ultimate conclusion being "It depends"

Oh, I was planning on being pretty specific with the post -- limiting it to drysuit + undergarment only. I figure it might make for a good discussion.

Here's a link to a wing buoyancy calculator on the board http://www.scubaboard.com/forums/bu...ems/158370-ultimate-wing-lift-calculator.html or you could give Tobin at DSS a call and let him recommend a wing. I'm willing to bet he recommends at least a 35lb wing, maybe even a 40lb for your setup.

It's funny you should mention Tobin. When I was shopping for a BP/W rig a few years ago, I contacted him and described my exposure suit and tank configuration. He recommended a wing with 30 lbs. of lift.

 

[Jon Nellis]

It's funny you should mention Tobin. When I was shopping for a BP/W rig a few years ago, I contacted him and described my exposure suit and tank configuration. He recommended a wing with 30 lbs. of lift.

Tobin's basic formula for MIN wing size swiped from TDS... The Deco Stop

Let's use a concrete example for discussing BC lift requirements. My drysuit + undergarment have about 24 lbs. of positive buoyancy. I use a total of 12 lbs. of lead. My tank is a HP100 steel that is 10.5 lbs. negatively buoyant when full. My stainless steel backplate is -6 lbs., my STA is -3 lbs., and reg is -2 lbs. My wing has 30 lbs. of lift. At the beginning of the dive, I have 12 lbs. of lead + 11 lbs. of other ballast (SS BP, STA, reg) + 10.5 lbs. contributed by the tank. In your opinion, is my wing undersized?

24lbs for your suit + 7lb for gas + 2-3 lbs extra = 33-34 lbs which is dead nuts on what you had listed at the beginning of a dive with your config. at 33.5lbs.

It doesn't appear I will convince you your wing is a bit undersized, but others reading this will at least be more informed.

 

[Bubbletrubble]

Tobin's basic formula for MIN wing size swiped from TDS... The Deco Stop

Jon, for the life of me, I have no idea why there's a discrepancy between the link you provide and the information that he gave me for my purchasing decision. All of the posts that Tobin has made on this board appear to use a different formula. I suspect that your linked post is an over-simplification...but I could be wrong about that. Perhaps the "+"s in Tobin's post refer to needing data A + data B + data C...rather than a straight algebraic sum.

AFAIK, a wing needs to be able to do the greater of: (a) being able to provide enough lift to keep the diver's rig afloat (without him in it) or (b) being able to provide enough lift to compensate for maximal loss of the positive buoyancy afforded by exposure protection (drysuit or wetsuit). By these criteria, my wing has enough lift.

FYI, DSS does not offer a 3 lb. STA. It was something that I added to place a little more non-ditchable weight on my rig. Since this only affects condition (a) from above and the wing can support this extra 3 lbs., the wing should still be large enough.

24lbs for your suit + 7lb for gas + 2-3 lbs extra = 33-34 lbs which is dead nuts on what you had listed at the beginning of a dive with your config. at 33.5lbs.

Sizing a wing properly depend on several things, one of which is how the ballast is distributed (on the diver vs. on the rig). As a diver adds more ballast to the rig, he needs to be aware of meeting condition (a) described earlier in this post. As a point of clarification, I think you're simply adding up numbers...and that's not the proper way to determine wing size.

I'll ask Tobin to weigh in on this issue, and I'll post back to this thread to settle this.

It doesn't appear I will convince you your wing is a bit undersized, but others reading this will at least be more informed.

I agree, Jon. I'd hate to have people be misinformed about something as important (and basic) as how to determine required lift for a wing.

If I'm wrong, I'll buy you a beer the next time I'm in Monterey.

Happy Easter.

 

[Bubbletrubble]

@Jon Nellis: I finally got around to posting the question directly to Tobin on the Deep Sea Supply manufacturer's forum. He responded very quickly. It appears that the Deco Stop post you linked to previously should only be used in assessing wing size for doubles. My configuration is for a single tank rig.

If you read the thread, you'll see that Tobin recommended that a Torus 26 lb. wing would be sufficient for my configuration...but the LCD 30 lb. wing would give more room for fluffier undergarments in the future. He also said that the 8 lb. bolt-on weight plates could be used with that configuration.

I hope this clarifies a few aspects of our discussion regarding wing sizing. I intend to purchase a DSS rig in the not-too-distant future, so I was particularly interested in getting Tobin's opinion on things.