Which wing for HP-120 doubles?

[ScubaTerp]

Hi everyone,

I have a pair of HP-120s that I bought from a friend. They're in good shape, but they're equipped with a dual bladder Super Wing. Personally I find the wing to be incredibly cumbersome and capable of much more lift than I need. I'll be diving these with a drysuit and steel BP. I have a couple of quesitons...

1) Which wing should I consider? I'd like the ditch the Super Wing and get something smaller and preferably with a single bladder. My drysuit will already act as a second BC if required, and I don't like the entanglement hazards. I was thinking of the classic wing. What are the differences between the EXP and the regular version?

2) Right now the drysuit, ultra warm undergarment, super wing, and steel BP configuration is just a little too light at the end of a dive. I struggle to maintain buoyancy around the 10' mark or so. I'm considering a Halcyon v-weight (probably the 8 lb one). Does anyone have an alternative suggestion?

3) What's the best way to determine how far up or down the bands should go on my doubles? I'm very tall (6'9"), so I probably need to lower the bands enough that I can reach the valves. Are there any other rules of thumb to work with, or should I just adjust it until I can reach them?

 

[Gombessa]

1) Which wing should I consider?

The buoyancy of double 120s when empty is not much different from other steel doubles. Assuming you're on air/nitrox, you're talking about 20+lb of gas when full, and the difference between this and your current setup is what you need any additional wing capacity to handle.

3) What's the best way to determine how far up or down the bands should go on my doubles?

The best rule of thumb I've heard is to keep the tank bands standard - right at the break of the crown - and fine-tune your reach and trim by adjusting harness positioning and weighting. One of the benefits of this is that you won't have become accustomed to a novel setup that makes it difficult to trim out or reach if you switch tanks or borrow/rent a set some time in the future.

 

[RJP]

Which wing for HP-120 doubles?

I dive double 119's and use a H Evolve 60 and find it works well. A couple of dollars more than the "ScubaBoard Sweetheart" brand that will no doubt be recommened in a post or two, but having both I find that I prefer the construction/fit/finish/components on the H to be a touch better, and of course there's the nifty blue H's.

 

[ScubaTerp]

The best rule of thumb I've heard is to keep the tank bands standard - right at the break of the crown - and fine-tune your reach and trim by adjusting harness positioning and weighting. One of the benefits of this is that you won't have become accustomed to a novel setup that makes it difficult to trim out or reach if you switch tanks or borrow/rent a set some time in the future.

Hrm, that might pose a problem. I'll give it a shot, but I'm not sure how much I can shift my harness. It's a single piece of webbing. Adjusting trim won't be a problem, but my main concern is being able to reach those valves.

 

[Gombessa]

Hrm, that might pose a problem. I'll give it a shot, but I'm not sure how much I can shift my harness. It's a single piece of webbing. Adjusting trim won't be a problem, but my main concern is being able to reach those valves.

A single continuous webbing harness is very easy to adjust, that's actually what I was referring to. However, I'm a bit confused by what you're saying. You're very tall, so you can't reach your valves? Most tall, lanky people I know have less trouble reaching their valves (and some can reach the valve on the opposite side of their arms). Is your plate too low on your back?

The positioning of the backplate on your body is determined based on being able to reach your hand up and back and (barely) touch the top edge of the plate; doing so puts the tanks in a position where you should be able to reach the valves, without messing with band positioning.

Does your plate have multiple sets of holes for tank positioning? If your tanks are too low as they currently are, you can try using a higher set of holes. Basically, almost any adjustments you can easily try are better than moving the tanks up and down the bands.

 

[cool_hardware52]

Hi everyone,

I have a pair of HP-120s that I bought from a friend. They're in good shape, but they're equipped with a dual bladder Super Wing. Personally I find the wing to be incredibly cumbersome and capable of much more lift than I need. I'll be diving these with a drysuit and steel BP. I have a couple of quesitons...

1) Which wing should I consider? I'd like the ditch the Super Wing and get something smaller and preferably with a single bladder. My drysuit will already act as a second BC if required, and I don't like the entanglement hazards. I was thinking of the classic wing. What are the differences between the EXP and the regular version?

2) Right now the drysuit, ultra warm undergarment, super wing, and steel BP configuration is just a little too light at the end of a dive. I struggle to maintain buoyancy around the 10' mark or so. I'm considering a Halcyon v-weight (probably the 8 lb one). Does anyone have an alternative suggestion?

3) What's the best way to determine how far up or down the bands should go on my doubles? I'm very tall (6'9"), so I probably need to lower the bands enough that I can reach the valves. Are there any other rules of thumb to work with, or should I just adjust it until I can reach them?

First off exactly what HP 120's? There are some 120's that are very negative.

The fabers are ~-7 lbs empty and the Heisers are -17lbs empty!

Most other "HP120's" are ~1-2 lbs empty.

With a wing that's almost guaranteed to trap gas it's hard to determine if you are now correctly weighted or not.

Minimum wing capacity can be determined by adding the weight of your back gas, the buoyancy of your exposure suit, then add 2-3 lbs extra.

2 x 120 x .08 = ~19 lb. (air or Nitrox) Call it 20 if you get a generous fill.

Put on your undies and drysuit. Find some neck deep water and jump in holding a big bag of lead. Vent your suit while you are standing.

Remove lead from the bag until you just barely sink when you pick up your feet. Weigh the bag of lead. Now you know the buoyancy of your suit with minimum gas in it.

**Example** You need to test your own suit and use your own numbers.

If your suit is +24 lbs with minimum gas in it you need a wing that's

24 (suit) + 20 (back gas) + 3 = 47 lbs.

If you start the dive negative by the weight of the gas you will need to use ~20 lbs of you available lift to remain at the surface, and you need to have in reserve enough additional lift to deal with a total failure of your drysuit.

The extra 3 lbs of ballast is to allow extra inflation gas in your suit at a shallow stop with empty back gas tanks.

Assuming your suit is +24, then it follows that you need a total of 27 lbs of ballast with empty tanks.

If 100% of your ballast is on your rig, plate, empty cylinders, tank bands, regs, manifold, v weight etc. then your rig with full tanks will be exactly equal to the 47 lbs we defined as the minimum lift required based on your suit.

27lbs. of ballast with empty tanks + 20 lbs of gas = 47 lbs.

If your rig alone is more than 27 lbs negative with empty tanks you need to change components such as a lightweight plate in lieu of a SS plate, or lighter cylinders if you are using the some of the very negative 120's I listed above.

If your rig is less than 27 lbs negative with empty tanks one easy cheap way to add ballast is to use soft weight pouches between wing and the back plate. Depending on the cylinders used and the back plate used one can fit 4-8 lbs in this void.

It should be apparent that required wing capacity is not a function of tank weight, but is a function of gas volume and exposure suit buoyancy.

Tobin

 

[ScubaTerp]

A single continuous webbing harness is very easy to adjust, that's actually what I was referring to. However, I'm a bit confused by what you're saying. You're very tall, so you can't reach your valves? Most tall, lanky people I know have less trouble reaching their valves (and some can reach the valve on the opposite side of their arms). Is your plate too low on your back?

The positioning of the backplate on your body is determined based on being able to reach your hand up and back and (barely) touch the top edge of the plate; doing so puts the tanks in a position where you should be able to reach the valves, without messing with band positioning.

Does your plate have multiple sets of holes for tank positioning? If your tanks are too low as they currently are, you can try using a higher set of holes. Basically, almost any adjustments you can easily try are better than moving the tanks up and down the bands.

Unfortunately I'm not lanky at all at about 285 lbs. I checked out my backplate, and sure enough the top edge of the plate is right where I can reach it. But when I put on my doubles I still can't reach the valves. I can barely reach the isolator right behind my head, but that's it. There's only one set of holes in the backplate for the tank.

EDIT:

cool_hardware52, thanks a lot for all that info. I'll try and see if I can get the buoyancy of my suit tomorrow (it's a 3XL Pinnacle Evolution). The tanks are Pressed Steel, and the first hydro was in 95.

EDIT 2:

Turns out putting 113 lbs of steel on your drags the plate down a bit. I'll try and adjust the straps, but I'm worried that if I make them too restrictive I won't be able to put them on. Thoughts?

 

[cool_hardware52]

Unfortunately I'm not lanky at all at about 285 lbs. I checked out my backplate, and sure enough the top edge of the plate is right where I can reach it. But when I put on my doubles I still can't reach the valves. I can barely reach the isolator right behind my head, but that's it. There's only one set of holes in the backplate for the tank.

EDIT:

cool_hardware52, thanks a lot for all that info. I'll try and see if I can get the buoyancy of my suit tomorrow (it's a 3XL Pinnacle Evolution). The tanks are Pressed Steel, and the first hydro was in 95.

EDIT 2:

Turns out putting 113 lbs of steel on your drags the plate down a bit. I'll try and adjust the straps, but I'm worried that if I make them too restrictive I won't be able to put them on. Thoughts?

I'd guess you plate may be too short for somebody 6'9". A longer plate will also help with donning.

Donning and doffing is mostly a mater of technique. Your harness need not be tight, but if you currently have really loose that's not going to help you reach your valves.

Remember you need to be able to reach your valves in the water, not in the parking lot. In the water your gear's not 113 lbs negative.

Tobin

 

[ScubaTerp]

I hadn't considered a longer plate. Where could I get one?

 

[Kern]

I hadn't considered a longer plate. Where could I get one?

PS. Sorry, didn't notice how new you were to the board.

https://www.deepseasupply.com/index.php?category=backplates