Yet another wing size thread...

[jagfish]

I'm finally going to do it, I'm buying my first backplate and wings. I've used the search button, but hoped that some of could offer some advice on my specific situation. I've decided on a Halcyon Eclipse MC. I thought I wanted a 40 lb wing... but after making a trip to a semi-local Halcyon dealer, I'm not so sure - the shop owner told me that a 30 lb should be "plenty" for me. I'm about 5'7 and somewhere in the range of 150 lbs. Diving in New England, I tend to wear a 6.5mm farmer john and while diving an AL80, I need about 22 lbs of lead. Not having my own tanks, I want to be able to dive any steel single I might reasonably run into. I realize that 30 lbs lift would probably be sufficient most of the time, but it's the thick wetsuit at depth (compression) that concerns me. Also, I wonder about being on the surface in rough conditions with a larger steel tank. The decision is made more difficult by the seemingly small difference in physical size between the two wings. Would a 40 lb wing be detrimental, as far as trim and safety? Or is the 30 clearly the better choice for me?


Thanks in advance,

Anthony

Wow...
I hate it when I post a question and the answers come in from every angle, usually resulting in me being more confused than when I first asked the question. Hope the answers for you gather around a "sweet spot" that you can resonate with.

I think basically, you won't go wrong with either wing. Our shop is a Halcyon dealer, so I have tried both the 30 and 40 Eclipse, though I own the 40. We use Eclipse 30s as rentals. I have on occasion led dives with customers for whom the lift provided by the 30 was marginal. This was during drysuit season, steel tanks, and bigger than you sound to be.

So I use the 40. I know there is no single tank configuration I will dive that can overpower the lift, and the profile difference with the 30 is negligible.

JAG

 

[halocline]

I've got to ask; what's a guy your size doing with 22 lbs of weight, even with a 6.5mm suit and an AL80? I must be missing something, but I'm about that size; maybe 10lbs heavier (meaning more bouyant, I believe) and if I strapped on that much lead I'd probably still be on the bottom...

I'm not trying to ruffle your feathers here, just wondering. If you could get your weight down, probably the smaller wing would work great, right?

 

[The Kraken]

Mattboy,
When diving an aluminum 80 and back inflation BC I require about 18 pounds of weight myself. And trust me, I've worked on this for a while.
Keep in mind that a 6.5 farmer john/jacket generates significantly more buoyancy than a 1 piece 7 mm full suit.
Anthony's numbers aren't that far off.
Individual buoyancy does not fall under a rigid scale of requirements.

 

[anth]

Wow, that's a lot of posts! Thanks guys, definitely something to think about... I guess what concerns me most is wetsuit compression (thick suit) combined with a tank full of air at the beginning of a dive... There are definitely some differing opinions out there!



-DSAO,

Anthony

 

[jonnythan]

A size medium 2 piece 7mm suit, hood, and gloves can be in the neighborhood of 18 lbs positive.

An empty Al 80 is about 5 pounds positive.

It's easy to see how 22 pounds would be required.

 

[The Kraken]

Anthony,
I don't know much about your diving history, but if you dive this setup be prepared for a significant change in buoyancy at about 13 feet or so. Your wetsuit undergoes a quite noticeable loss of buoyancy due to compression and you can start descending rather quickly with very little warning. After the first couple of experiences with it it'll just become a part of your regular diving scenario and you'll be prepared for it.

 

[anth]

Jonnythan - Thanks for justifying my weighting, I knew I wasn't terribly overweighted! I've actually taken off a few pounds in the past year.

The Kraken - I've been diving the THICK wetsuit set-up for awhile now, you're very right, the bouyancy shift is definitely noticable with the suit compression, but I think I've grown acustomed to it.

Thanks again!

-Anthony

 

[lamont]

I'm going to go against the grain and suggest that you plan your wing size for a worst-possible case. If you are not /always/ going to be diving in places with hard floors above 165 fsw, assume that you may wind up
at 165 fsw with no buoyancy from your wetsuit with a full tank of gas and need to get up. so the math
looks something like:

compressed wetsuit = 0# (loss of buoyancy, unplanned trip to 165 fsw, being conservative)
full E8-130 = -10# (LP104s are more negative, but more weight comes off the belt)
weightbelt = -17# (probably less, being conservative)
steel backplate? = -5#?
can light? = -1#?

starting with 27#, a 30# rated wing doesn't give you much room for error. I'd go with the 40# wing.

of course it can be argued that in that situation the weightbelt could be ditched, but then you'd polaris from 165 fsw after you wetsuit expanded again on the way up, and I don't think that's good planning...

i also like sitting a bit higher out of the water, and being able to do things like handle other people's weightbelts on the surface, etc, and i just like the room for error that a 40# wing gives over a 30# wing.

 

[cool_hardware52]

I'm going to go against the grain and suggest that you plan your wing size for a worst-possible case. If you are not /always/ going to be diving in places with hard floors above 165 fsw, assume that you may wind up
at 165 fsw with no buoyancy from your wetsuit with a full tank of gas and need to get up. so the math
looks something like:

compressed wetsuit = 0# (loss of buoyancy, unplanned trip to 165 fsw, being conservative)
full E8-130 = -10# (LP104s are more negative, but more weight comes off the belt)
weightbelt = -17# (probably less, being conservative)
steel backplate? = -5#?
can light? = -1#?

starting with 27#, a 30# rated wing doesn't give you much room for error. I'd go with the 40# wing.

of course it can be argued that in that situation the weightbelt could be ditched, but then you'd polaris from 165 fsw after you wetsuit expanded again on the way up, and I don't think that's good planning...

i also like sitting a bit higher out of the water, and being able to do things like handle other people's weightbelts on the surface, etc, and i just like the room for error that a 40# wing gives over a 30# wing.

Lamont,

Your example is pretty extreme. Why is your diver so over weighted? -27 lbs to sink a 6.5 mil wet suit? With a compressible wetsuit one does not need to be overweighted by the weight of 100% of the gas in the tank at the beginning of the dive. At 15ft the suit has lost quite a bit of it's buoyancy, allowing you to hold the 15ft stop.

When you use the E-8 take some off the belt.....

I use 8-12 lbs on a XSscuba pouch type weight belt. I like the idea that I can easily open a single pouch and remove 2 or 3 lbs at a time, no "polaris". I've never had occassion to drop weight, but I still like the idea. I also like the idea better than ditching a $$ can light.

I agree that an overweighted diver, unable to control their buoyancy sufficiently to avoid unintended trips to -165 fsw, with a single tank,even a E-8, is in trouble, regardless of the lift wing they are using.....

Am I missing something here?


Regards,



Tobin

 

[lamont]

Lamont,

Your example is pretty extreme. Why is your diver so over weighted? -27 lbs to sink a 6.5 mil wet suit? With a compressible wetsuit one does not need to be overweighted by the weight of 100% of the gas in the tank at the beginning of the dive. At 15ft the suit has lost quite a bit of it's buoyancy, allowing you to hold the 15ft stop.

Hmmm... Okay, I dive dry, so I don't know what to say about weighting issues like that. What do you do if you accidentally pop up from 10 fsw though and need to get down at the end of the dive? This can happen easily due to a runaway inflator. I guess single tank wetsuit divers aren't doing deco, though, so staying on the surface may be a perfectly acceptable answer (getting into the missed safety stop thread discussion there...)

When you use the E-8 take some off the belt.....

I did take off 5 lbs from the example given going from 22 lbs + AL80 to 17 lbs + E8-130.

I use 8-12 lbs on a XSscuba pouch type weight belt. I like the idea that I can easily open a single pouch and remove 2 or 3 lbs at a time, no "polaris". I've never had occassion to drop weight, but I still like the idea. I also like the idea better than ditching a $$ can light.

Generally, I don't like plans that involve ditching weight, though, even a little bit of it. Of course if you're down there with a compressed wetsuit and a tear in the wing, bent is better than drowned. With a functioning wing, though, I'd think the better plan would be to have the wing get you out of any forseeable trouble without ditching.

I agree that an overweighted diver, unable to control their buoyancy sufficiently to avoid unintended trips to -165 fsw, with a single tank,even a E-8, is in trouble, regardless of the lift wing they are using.....

Could happen even to an experienced diver with a sudden downwelling, tsunami, or other random occurance of luck running out...

Am I missing something here?

I don't think so. I think its all arguable.