BP/W for me and my son?
- Thread starter Mark Lem
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That is NOT cricket!
halocline
Contributor
I guess I walked into that one.
It's impressive how shameless you are about using this board for sales pitches. Your response to a fairly caustic post of mine criticizing you for that was.....another sales pitch. Good one!
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For the same diver: 5'6" & 109 lbs, new 7 mm full suit, hood, gloves & boots with a buoyancy of 18 lbs with an AL 80 cylinder
Best BP/W for only cold water diving?
Best BP/W for only cold water diving?
cool_hardware52
Contributor
Assuming the *suit* alone is +18 lbs I would suggest the following:
Medium SS plate
LCD 20 wing
Hogarthian Harness
The divers rig will be ~ -10 bls with a full cylinder. 6 lbs of Plate and Harness, 2 lbs of reg and 2 lbs of full al 80.
10 lbs < 20
The diver's suit is +18 18 < 20
Minimum ballast allows the diver to maintain a shallow stop with an empty tank. The rig will provide about 4 lbs of ballast with an empty cylinder.
At first glance it looks like he diver will need 18 - 4 = 14 lbs in a weight belt.
That's probably not the case. His wetsuit will be considerably less buoyant at ~15 ft or 1.5 ATA than it was at the surface.
In a buoyant suit i would guess the diver will need about 12-14 lbs of total ballast with an empty cylinder to hold a 15 ft stop with an empty tank.
12-4 leaves 8 lbs on the belt. The vast majority of divers can easily tolerate 4-6-8 lbs weight belts.
In *thick suits* and when using normal sized single cylinders I recommend the diver adjust their weighting so they are eye level at the surface with no gas in their wing and a full cylinder.
The compression of the exposure sit from the surface (1 ata) to 15 ft (~1.5 ata) will offset the the weight of the gas consumed during the dive.
****Special note for Stuart V, this won't work in thin suits or doubles or huge singles (Heiser 190's) ****
Let's look at our diver. They are eye level at the surface with a full tank. They have ***100%*** of their wing's capacity to get their chin out of the water.
The wing can float their rig if they ditch it. If they do ditch there is no need to drop their weight belt, they are wrapped in 18 lbs or positive neoprene, and wearing maybe 8 lbs of weight belt 18 > 8
The wing can compensate for the complete, total, maximum compression of their wetsuit, and one needs to dive to ~190 FSW to fully compress most neoprene, bad idea on a single tank.
Under what conditions would i recommend a larger wing?
1) If I have a low level of confidence in the buoyancy number for the suit provided, "Er ah well I don't actually have the suit yet, but I'd like you to guess how buoyant it is" I hear this frequently.
2) If there is a good chance the diver will be adding more exposure suit. When new divers get comfortable in their own well fitting BC bottom times get longer, and energy expenditure drops, both often lead divers to seek more suit, hooded vest etc. There are of course limits to trying to future proof divers, or the wings gets huge and some of the benefits of a BP&W are lost.
I also explain to my customers when the goods i've recommended for specific application are no longer appropriate. i.e. more buoyant suit, steel cylinders vs al 80s etc.
Tobin
Last edited:
eelnoraa
Contributor
Can we make the last post sticky?
5'06" 110 lb
---------- Post added September 3rd, 2015 at 02:21 PM ----------
I think Tobin just covered his scenario with above post
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