dry suit weighting question

[Lobzilla]

+1 on a class with a good instructor.

By the time I got a drysuit, I had two wetsuits, doubles, singles, in aluminum and steel, etc.

Instead of trying numerous combinations, I spent a few hours in the pool measuring the buoyancy of the negative items with a luggage scale. Then, I put on a rig and figured out how much lead I needed to sink with a suit. By adding the negative buoyancy from the rig plus the lead I could calculate the positive buoyancy of me in the suit. Then, I got more data points for different undergarments and/or other suits to complete the list. (The influence of additional garments is easy to guesstimate if you mentally or literally stuff them tightly in a bucket. One gallon of additional bulk makes you about 8 pounds lighter)

While this sounds complicated, the resulting list allows me to dive ANY combination of all items without additional check. It also becomes obvious what combinations are fundamentally not such a great idea. And finally, by weighing all items dry on a scale I could calculate their buoyancy in salt water. A few hours saved days of uncertainty and trial/error.

Of course, the remaining question is weight distribution and the effect on trim. In aviation we even do that on paper but I am not going to go there for diving. It becomes pretty obvious what drops your nose and what drops your tail.

 

[ncullinan5]

Hi
I am 120# and wear 18# with a 7.5 mil and a skin now i started to dive a DUI TLS 350 and i wear 20# with ankle weights.

It depended what your dry suit is made of crushed neoprene floats but trilam is not buoyant. I just bought a DUI Flex 50/50 and i will need to redo the weighting due to the change in material

 

[msimp2005]

I agree you should not dive alone. I think you should def. find a buddy to dive with.

 

[EastTNDiver]

You will need to dive at least once a bit under weighted just to realize the sensation. Its not like a w/s where you can't descend, more like being vacuum packed. I ended up at +6lbs over my 7MM weight if that helps.

That's exactly where I ended up too.

For another comparative example for the OP, I am 5'9"...190 pounds...dive a DUI TLS 350 drysuit...Weezle Extreme undergarment...single steel 95...Halcyon SS BP/W...fresh water quarry...don't like my drysuit fully lofted (slight squeeze)...16 pounds of lead.

 

[fire_diver]

I agree you should not dive alone. I think you should def. find a buddy to dive with.

That's not what the OP asked about.

 

[Thalassamania]

This only has an empirical answer: the amount of weight needed to make you neutral when gently "shrink wrapped" at 10 feet with a tank(s) that contains your desired reserve amount of gas.

 

[11x]

I agree you should not dive alone. I think you should def. find a buddy to dive with.

i have a dive buddy but some times he likes to make fun of me and hurts my fealings :mooner: lol

 

[oldflounder]

+1 on a class with a good instructor.

By the time I got a drysuit, I had two wetsuits, doubles, singles, in aluminum and steel, etc.

Instead of trying numerous combinations, I spent a few hours in the pool measuring the buoyancy of the negative items with a luggage scale. Then, I put on a rig and figured out how much lead I needed to sink with a suit. By adding the negative buoyancy from the rig plus the lead I could calculate the positive buoyancy of me in the suit. Then, I got more data points for different undergarments and/or other suits to complete the list. (The influence of additional garments is easy to guesstimate if you mentally or literally stuff them tightly in a bucket. One gallon of additional bulk makes you about 8 pounds lighter)

While this sounds complicated, the resulting list allows me to dive ANY combination of all items without additional check. It also becomes obvious what combinations are fundamentally not such a great idea. And finally, by weighing all items dry on a scale I could calculate their buoyancy in salt water. A few hours saved days of uncertainty and trial/error.

Of course, the remaining question is weight distribution and the effect on trim. In aviation we even do that on paper but I am not going to go there for diving. It becomes pretty obvious what drops your nose and what drops your tail.

Claus - The idea of stuffing your dive clothing into a bucket and weighing it is interesting. You could take a clean 5 gallon bucket from Home Depot for example - invert it in the pool and suspend weights from the handle under it was just submerged. This would give you the weight of the bucket full of air. You could get the weight of the bucket itself also by sinking it full of water till it just went under. [I think a plastic bucket is a little positively buoyant.]

Next you could put the garments you are planning to wear diving in a thin plastic bag [to keep them dry] and remove as much air as possible. Stuff this bag into your 5 gallon bucket and invert it in the pool and again add weights to the handle until it was barely submerged. The difference between the bucket full of air and the bucket full of clothes should give you the positive buoyancy of the clothing [dry] - even if there was air left in the bucket, if the plastic bag didn't fill it full.

And if you are really interested - you could saturate the clothing for an hour or so - submerge these in the bucket and weigh it to get the buoyancy of the air that used to be in the fabric that has been replaced by water when saturated.

This way you could figure out the buoyancy effect of different undergarment configurations to your main gear setup[fins,bcd, mask,clip-ons, etc.] without trying them on underwater and doing a bunch of neutral buoyancy tests. Make sense???

 

[msimp2005]

That's not what the OP asked about.

lol who cares if that was the orginal post. its a forum and he's my dive buddy i was giving him a hard time.

 

[vshearer]

I just started diving dry. I hated being overweighted wet, but being underweighted dry sucks more.