Weight distribution with drysuit (another wing lift question)

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walrus2

Contributor
Messages
232
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Location
Calgary
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200 - 499
Hi,

I'm trying to figure out required wing lift and weight distribution. I need ca. 43 lbs of weight total (Al80, not practical to switch in general). I suppose it's possible the usual replies on being overweighted will crop up, but let's assume that's the right amount of weight. I had this divided over a SS bp (5 lbs), a 20 lb weight belt, and 18 lbs in weight pockets on my harness.

Question: how do people with a similar amount of weight distribute this over a weight belt and the rig? Or even if you need 30 pounds, how much of that goes on a weight belt vs. harness?

With this amount there's 23 lbs on the harness, plus 2-3 for my reg, 2 for a full Al80, 2 for a can light, plus some other metal pieces - ca. 30 lbs. If I want a wing to float this rig with a full tank 30 is cutting it close. But I understand I'm going to die if I need more than 30 Lbs for a single tank ...

If I'd be able to use a larger steel tank on occasion, I could use a lighter weight belt but in that case I'd need more than 30 lb lift to float the rig with a full tank. Or I could take weight off the harness and stay around 30.

I understand 30 lbs lift is easily enough to compensate for gas use and non-existent drysuit compression at depth, and even with a full HP120 I'd initially only use a third of the wing capacity. The key point here seems to be floating the rig on the surface, and this depends on how I distribute my ballast.

Thanks for any suggestions.
 
Hi,

I'm trying to figure out required wing lift and weight distribution. I need ca. 43 lbs of weight total (Al80, not practical to switch in general). I suppose it's possible the usual replies on being overweighted will crop up, but let's assume that's the right amount of weight. I had this divided over a SS bp (5 lbs), a 20 lb weight belt, and 18 lbs in weight pockets on my harness.

Question: how do people with a similar amount of weight distribute this over a weight belt and the rig? Or even if you need 30 pounds, how much of that goes on a weight belt vs. harness?

With this amount there's 23 lbs on the harness, plus 2-3 for my reg, 2 for a full Al80, 2 for a can light, plus some other metal pieces - ca. 30 lbs. If I want a wing to float this rig with a full tank 30 is cutting it close. But I understand I'm going to die if I need more than 30 Lbs for a single tank ...

If I'd be able to use a larger steel tank on occasion, I could use a lighter weight belt but in that case I'd need more than 30 lb lift to float the rig with a full tank. Or I could take weight off the harness and stay around 30.

I understand 30 lbs lift is easily enough to compensate for gas use and non-existent drysuit compression at depth, and even with a full HP120 I'd initially only use a third of the wing capacity. The key point here seems to be floating the rig on the surface, and this depends on how I distribute my ballast.

Thanks for any suggestions.

Why do you need 43 lbs of ballast? If you are correctly weighted, (and I do have my doubts) then we can assume that 4lbs of these 43lbs are required to compensate for an empty and buoyant al 80 at the end of the dive.

That leaves 43 -4 = 39 lbs of ballast required to compensate for the buoyancy of your drysuit.

That's on the extreme upper limit, possible, but unlikely.

Keep in mind that in the event of a total failure of your drysuit it is possible to loose all the buoyancy the suit provides.

If your suit is really +39 a 30 lbs wing is dangerously undersized.

I'd suggest you test your suit's buoyancy.

Put on your undies and suit and find some neck deep water.

Bring a bag of "too much lead", just in and vent your suit while standing.

Remove lead until you just sink when you pick up your feet. Weigh the bag o lead.

Now you know what the buoyancy of your suit is with minimum gas in it.

Minimum ballast will equal the buoyancy of your suit + the buoyancy of your empty al 80.

Tobin
 
Thanks. 43 is accounting for the empty tank. It's possible I'm overweighted but not by 9 pounds. I'm 6'4, 220lb, 40F salt water. Based on other threads about weight/drysuits >30 pounds in PNW/BC seems fairly common. On the other hand, there's also a common suggestion noone (except some extremes :)) needs more than 30 pounds lift.

Another example: if you would use an HP120, DSS's SS BP and weight plates you're at 30 pounds with a full tank if you account for reg and some other bits. This seems a sensible approach for diving in BC.

Maybe my impression on this board that larger than 30 lbs wings are as bad as split fins and snorkels is wrong.

I'm still interested in how people divide weight over a weight belt and harness.
 
Thanks. 43 is accounting for the empty tank. It's possible I'm overweighted but not by 9 pounds. I'm 6'4, 220lb, 40F salt water. Based on other threads about weight/drysuits >30 pounds in PNW/BC seems fairly common. On the other hand, there's also a common suggestion noone (except some extremes :)) needs more than 30 pounds lift.

Another example: if you would use an HP120, DSS's SS BP and weight plates you're at 30 pounds with a full tank if you account for reg and some other bits. This seems a sensible approach for diving in BC.

Maybe my impression on this board that larger than 30 lbs wings are as bad as split fins and snorkels is wrong.

I'm still interested in how people divide weight over a weight belt and harness.

There are certainly applications for single wings of greater than 30 lbs capacity, just not many.

If your suit is more than 30 lbs buoyant a 30 lbs wing is too small.

Regarding distribution, think about it this way.

With an empty tank your total ballast needs to equal the buoyancy of your suit with minimum gas in it.

If you hang all of your ballast on your rig, SS plate, weight plates, weight pockets, negative steel cylinder etc. then maximum negative buoyancy of your rig will be

Total ballast + weight of gas,

That will always be greater than the buoyancy of your suit, and will require a larger wing than would be required if a portion of your ballast is carried on your person, i.e. in a weight belt.

For example:

If we assume your suit is actually +35 lbs and you are using a 80 cuft cylinder.

If all your ballast is on your rig it needs to be -36 with no gas, and will be about -41 with a full tank. To float your rig you need ~45 lbs wing.


OTOH if you carry ~8 lbs in a belt your rig will be 41-8 = 33 lbs negative with a full tank.

Here a 35 lbs wing can both compensate for a failed drysuit, and it's large enough to float the rig.

In general in cold water I like to see 6-8lbs min in a belt.

Tobin
 
Tobin makes some great points about figuring out your proper weighting. To your original question about weight distribution, I have my BP/W singles rig setup with a 5lb v-weight, and two 5lb pockets on the lower cam band. Using this setup allows me to keep from having to put any weight on a belt or on my waist strap. I hope this helps.
 
Maybe the first question to ask is what are you wearing for thermal protection? To need 40# it must be awfully bulky.
 
Tell us about your undergarments. Do you get the least bit chilled at the end of an hour dive? If not, it's possible that you are more or less correctly weighted in total weight with the aluminum 80.

More than likely if that's not the case then you probably are at least 5 pounds overweight.

I have a 40lb DSS wing as I recall. At the time a 35lb horseshoe wing wasn't available.

I'm in the PNW, 6'1" 190 lb and use 22 lb on my weight belt, 5lb ss BP but have a HP 119 which takes off about 8 lb I believe.

I am a little chilled after a 1 hour dive. I had an almost arctic undergarment once that required an additional 5-8 lb of lead but I wasn't cold at all after an hour. I decided the trade off wasn't worth it.

Unless you have such an undergarment (and my current undergarments are quite bulky as well) then you may be able to drop a little weight. I don't use any on the harness.

But you are right, greater than 30 lb if using an alum.80 in the PNW is quite common (and necessary). If you're waters at 40 degree F then you may be correctly weighted. The range here is 46-54 but 48-50 is the most common.
 
Thanks for the replies.

I was using rental gear, Tusa underwear plus polypro liners and double ski socks in dry socks on the CF200 and 7mm wetsuit booties. I don't know exactly what the Tusa was, I do realize that is the most interesting piece. Drysuit was an old CF200. Warmth inside the drysuit was fine, but my hands would get very cold well before an hour (7 mm wet gloves). 7 mm hood, which was warm enough. Although it was rental gear I used the same stuff for about 40 dives and did have enough opportunity to play around with weighting at 500 psi.

I'm not trying to optimize this setup, I'm trying to make sure I understand optimizing a new setup. I'm buying a TLS350 with Actionwear underwear and dry gloves. I'm also considering switching from a harness with integrated weight pockets (Apeks) to a simpler harness, with all the usual options for putting weight on it (including pockets, plates, STA etc).

I will do what Tobin suggested and try to test the buoyancy of this new suit and underwear (I hope to get both in the next few weeks), and will need to play with underwear as I don't know how warm the new stuff is.

However, even if I was overweighted by 5 pounds, or turn out to need 35 pounds instead of 39 that doesn't really change my question about wing lift or weight distribution much. The dive shop owner guessed at 36 pounds for fresh water. That's the same ball park as my experience in Vancouver (2.5%*300 pounds + 36) but I realize this was just a guess.

For what it's worth, I actually use/used a 45 lb wing and had 20 + 9 + 9 ditchable weight. I'm aware that a drysuit failure or dropping a heavy weight is a problem.

Thanks!
 
I hate being cold. I use a White's Fusion with the White's MK3 undergarment and a 200g Thinsulate vest under it, and dive an LP95, and I need 31 pounds of ballast to be properly weighted in that setup. I use a 20 lb weight belt, 5 lb SS backplate, and 6 pounds on the cambands, and a 30 lb horseshoe wing. That arrangement will allow the rig to float at the surface without difficulty, and I trim out horizontal with it. In the event of a complete drysuit flood, I would need to shed weight, but I also carry an SMB and dive with a buddy, and my drysuit floods so far have all been gradual (nor do I dive in water that cold in any kind of environment where I would be likely to rip my drysuit wide open).
 
Peter, with an al 80 I use 20 lb weight belt, 5 lb steel backplate 5 lb steel sta and the rest of my gear, can light, regs, pony/reg. With steel 130 I drop the steel sta for a light weight two piece sta.
You can add weight to your rig with weight pockets on the cam bands and or pockets on your waist belt butted right up to the plate. It's going to take some thinking to keep your over all weight manageable for traveling. The other option a lot of people use is a dui weight harness. You can get a lot of weight in that and it's distributed over your shoulders.

Ron L.
 
https://www.shearwater.com/products/peregrine/

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