Halcyon Backplate Question

[MarcHall]

Backup buoyancy = drysuit. Ditching weight with a wetsuit is a total non-option becaue there is no chance you'd be able to control an ascent with neoprene. There are other ways to get to the surface than "missle-like."

Who is advocating missle-like acents ???

Well let me see if I can convice you otherwise.

Would you be willing to consider the following :

Two critical points of weighting on a dive.

1. At the end of the dive you need to be able to have enough weight to hold your deco stop with your tanks nearly empty. (Be neutral at 10 feet at the end of the dive).

2. At the beginning of the dive, at depth you need to be able to swim the system to the surface with a wing failure. Say we are diving a set of doubles alone. Due to the gas consumption during the dive we will have a shift in bouyancy of around 12-15 lbs depending on the amount of gas consumed and size of the doubles. If there is He in the tanks then the shift will be less.

If we weight ourselves so that we can be neutrally bouyant at the end the dive at 10 feet then at the start of the dive we will be 12-15 lbs negatively bouyant - lets call it 12.

If at the beginning of dive, we have a wing failure and we ditch say 10 lbs of weight then at 10 feet we will still be 2 lbs negative.

At the end of dive the ditching of 10lbs would not be a valid solution to the problem, but you will have consumed the gas and will not be so negative so it should not be needed.

What do you think ??

Marc Hall
www.enjoythedive.com

 

[MarcHall]

... I'll have to get together with Peo for some lessons on swimming up loaded 104s with empty wing and the suit squeezed.

I am not advocating diving a squeezed suit. I keep enough gas in my suit to avoid being squeezed. I don't like the welts. :->

The team is clearly a resouce to help solve any problems. I am in no way advocating solo diving.

I am suggesting that if you are so negatively bouyant at depth that you could not swim you rig to surface then perhaps you need to look at ways to deal with why you are so negative.

If you are wearing a wetsuit, then you might consider switching to a drysuit made of non-compressable material (ie TLS 350) or diving a different set of tanks such as AL80s.

If you are diving a drysuit, a SS plate, steel doubles and perhaps a V-weight then perhaps you should look at some modifications to your system.

Many people dive a SS plate with doubles just because it is what worked for them when they dived singles or because it is what their buddies dive without looking at how it effects their bouyancy. An aluminum backplate might be more appropriate and it's a small investment. A V-weight might not be needed or ditchable weight might be a more appropriate option.

As far as solving a flooded suit issue, water is neutrally bouyant in water. The displaced gas could be an issue but would be less so if thininsulate undergarments were worn as they would retain their bouyancy. On the surface bouyancy could be obtained with disposable weight rather then going with a larger wing.

Enjoy

Marc Hall
www.enjoythedive.com

 

[Uncle Pug]

Marc... have you ever had a totally flooded drysuit? Does Thinsulate have inherent buoyancy even when totally flooded? How much buoyancy did your thinsulate supply?

 

[jonnythan]

If at the beginning of dive, we have a wing failure and we ditch say 10 lbs of weight then at 10 feet we will still be 2 lbs negative.

Until you breathe 2 pounds of gas..