Weighting for HP 119 vs AL80

[Scubanoobi]

Looking for some advice to make sure I'm not missing something. Been diving AL 80's for the last 3 years and fine tuning my weighting. I needed 14 pounds with the following configuration in fresh water (and had to fight to get down):

Diverite Transpac (soft backplate - neutral buoyancy)
7mm full suit + boots, and hooded vest.
AL 80
The usual other stuff for scuba.

Recently bought a Worthington HP119. Looking at the specs, it's -2 empty compared to +4.4 for the AL80. So I decided to drop 6 pounds so down to 8.

Today I decided to get the HP 119 down to 500 psi at 15 feet and see how much weight I could shed, to my surprise, all of it! I don't need any weight, does this make sense? Could I have been that overweighted? I spent a lot of time on this over the years...

Did I miss something? 14 pounds!

 

[matt_w]

Weighting is very personal and depends a lot on body fat and your comfort level. I am not sure your experiment shows you were overweighted (you took off 6 pounds with a 6 pound difference in tank buoyancy). However, I suspect you were overweighed and maybe still are. Next time you get your tank down to 500 psi, if you are some place you can hang out on the surface you should try doing a proper weight check to see how much you really need with the tank at 500.

 

[Scubanoobi]

Matt, to clarify - I don't need any weight with the steel. I'll have to do another check with the AL80.

 

[luscioman]

I warm salt water with a rash guard I wore 12lbs with an alum 80. When I switched to a steel Faber HP 100 I dropped to 6 lbs.

 

[Scubanoobi]

6 pounds is what I would expect. Theoretically I should be able to go with 6 pounds on my 80 now, I don't think I'll be able to get down though

 

[lemke]

And if you go to a SS backplate and wing, you won't need any weight!

 

[fbk]

That 7mm suit takes a bit to compress and get below the surface... it has probably lost 6lb of buoyancy by the end of a dive at 15 feet, compared to the surface. When I started shedding my weights and was wearing thicker suits I found I had to duck dive and go head first to begin an ascent which to beginners and OW students is taught as being "under weighted". Which is why it is so often repeated that weight checks are best done at 15ft with a near empty tank as this determines the minimum weight you can get away with. The whole "mask at eye level on surface then descend feet first" is BS if you ask me but I guess it is what works for students.

 

[DogDiver]

Worthington's are ball busters. The most negative cylinders on the market.


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[Bopper]

The only way it seems like it would make sense to me is if your wetsuit lost 8lbs of buoyancy at 15ft. But even then, you said you had to "fight to get down" which would tell me you were still slightly positive and so you'd actually have to lose more than 8lbs of buoyancy to hold a safety stop. Personally, I've stopped worrying too much about dialing in exact weighting. I know it's blasphemy but...meh...<shrugs>

 

[Billy Northrup]

All kinds of air pockets and non water logged parts at first until you get down and get it all burped. The weight check at the end of the dive can be more accurate. I have a few different tanks and I started taking a sharpy and writing the weight I need on it instead of some mental reference to an AL80