Bp/w Recommendations

[yoni]

so. here is what is going on, this is slightly exaggerated, but not terribly so.
Warm water, swim trunks, steel tank. SS backplate makes you dangerously overweighted. With an aluminum tank, you shouldn't need a wing at all, so you want one that can comfortably keep you at the surface, so a 20lb wing is more than enough. With a large steel tank, say a 17l, you are compensating for 10lbs of air that you're going to breathe so you NEED a wing. Add in a stainless steel backplate, and you are dangerously overweighted for that environment.

Cold water, 7mm farmer john wetsuit, big steel tank, it is quite possible to need close to 40lbs of lift in the wing to compensate for the swing. A 40lb wing on an 8" diameter tank, is very different than on an AL80 in the caribbean, and as such you shouldn't use a wing quite that big in both environments. Now, the reason we have to ask for the ballast numbers you have, is because if say the 30lb wing is enough for your winter environment, you can easily use that in the caribbean, it is just slightly less ideal, but not unsafe. Requiring a lightweight plate for single tank diving is usually limited to steel tank use in warm water with no exposure protection in my experience, but most divers that dive in cold water, say most of Europe or the West Coast will have two wings, one for their local diving environment in the 40lb range, and one in the 20lb range for travel diving. If the 30lb wing is enough, it is an OK compromise to have one wing, but if it isn't enough, the 40lb wing is really far too large for swim trunk diving.

I understand what you are saying, although there are still a couple of points that just don't sit well with me, and it's probably because of my lack of knowledge pertaining to BP&W.
1. Using a regular BC, I am embarrassed to say here in this forum how much weight I need to go down with a 7mm wetsuit. I use very little air in the BC (if any) during the dive even on a deep dive. Is a BP&W so different that with a 7mm wetsuit I would need to compensate with such a big wing (40lbs)? I don't know how much lift my current BC has, but I am sure it's not even close.
2. How heavy are the SS plates? I thought that they are about 2lbs give or take (I couldn't find where it says on the site). In my present situation, with a standard BC and a 15L steel tank, I use more than 2lbs in weight to go down even when in a bathing suit. I do suspect that my BC doesn't dump out all it's air, causing it to have a more positive buoyancy than it should. But still, warm water, swim trunks, 15L steel tank. SS backplate will make me dangerously overweight?

I totally agree with what you are saying about stability in the water. My BC with integrated weights is horrible, especially with a 7mm suit. But with the 3mm or bathing suit it does OK, as long as I add some weigh in the back (trim).
So if I understood correctly, it would be better if, at the very least, I get 2 plates, 1 SS and one light one (Kydex or aluminum). Would that mean another harness as well?

 

[cool_hardware52]

I understand what you are saying, although there are still a couple of points that just don't sit well with me, and it's probably because of my lack of knowledge pertaining to BP&W.
1. Using a regular BC, I am embarrassed to say here in this forum how much weight I need to go down with a 7mm wetsuit. I use very little air in the BC (if any) during the dive even on a deep dive. Is a BP&W so different that with a 7mm wetsuit I would need to compensate with such a big wing (40lbs)? I don't know how much lift my current BC has, but I am sure it's not even close.
2. How heavy are the SS plates? I thought that they are about 2lbs give or take (I couldn't find where it says on the site). In my present situation, with a standard BC and a 15L steel tank, I use more than 2lbs in weight to go down even when in a bathing suit. I do suspect that my BC doesn't dump out all it's air, causing it to have a more positive buoyancy than it should. But still, warm water, swim trunks, 15L steel tank. SS backplate will make me dangerously overweight?

I totally agree with what you are saying about stability in the water. My BC with integrated weights is horrible, especially with a 7mm suit. But with the 3mm or bathing suit it does OK, as long as I add some weigh in the back (trim).
So if I understood correctly, it would be better if, at the very least, I get 2 plates, 1 SS and one light one (Kydex or aluminum). Would that mean another harness as well?

It's very common for jacket BC to have 35-50 lbs of lift. You don't need anywhere near that much. How much will be function of the buoyancy of your most buoyant suit.


The typical SS Plate and harness is about -6 lbs, the typical Lightweight plate and harness is about -2 lbs.

If you use at least a 3mm and buoyant al 80's a SS plate is near ideal. It's when you use little to no exposure suit and / or negative steel tanks that the SS plates will over weight you.

Where to start? Test your 7mm suit. I'm make an "EWAG" that it is 18-24 lbs positive hood and all.

Tobin

 

[yoni]

OK Will do. Although it may take me a day or two to get around to it.
I very much appreciate all your help and explanations.

 

[dmaziuk]

2. How heavy are the SS plates? I thought that they are about 2lbs give or take (I couldn't find where it says on the site). In my present situation, with a standard BC and a 15L steel tank, I use more than 2lbs in weight to go down even when in a bathing suit. I do suspect that my BC doesn't dump out all it's air, causing it to have a more positive buoyancy than it should. But still, warm water, swim trunks, 15L steel tank. SS backplate will make me dangerously overweight?

To give you some real-life numbers, in a pool (fresh water), Al plate, 2 mm shorty, and and empty AL80 I can float comfortably at 3-4 m depth with 1 kg of lead. A steel plate would be about 2 kgs heavier so with a steel plate I'd be a kilo too heavy. I wouldn't call that "dangerous" but still: with a steel plate in fresh water I'd be overweight with no ditchable weights. Of course with full AL80 at the start of a dive I'd be some 3 kgs heavier, and with a larger/steel tank -- more so, but a thicker suit would add buoyancy, as would salt water -- dep. on salinity, and so on and so forth.

The other issue is if you travel between the Red Sea and Med, steel plate means 2 extra kilos in luggage weight.

 

[yoni]

Well that's the part that I don't understand. First of all, I have never dived in fresh water - always salt water. This means more weight. With an empty aluminum tank you said that you "float comfortably at 3-4m". I am assuming that you mean floating at the surface. If you float comfortably at the surface, how do you manage to stay underwater at the end of the dive at 3 m? That is a major problem for me because if I would be weighed like that, I would be shooting up to the surface at the first hint of breathing. Which is why I take a little extra weigh.
I totally understand the problem of "undumpable" weight, and the fact that a SS plate may not be my best choice at this point. But I believe that I would need more weight than what you are talking about, especially with an aluminum tank.
The traveling between the Red Sea and Mediterranean is a few hours by car. No biggy, although I am surprised at the weight of a SS plate. Thought they were lighter.

 

[cool_hardware52]

Yoni,

Most reasonable fit people are pretty close to neutral in salt water, oddly enough we are largely made of salt water.

Why then do divers need ballast? Because diver often add buoyant exposure suits and sometimes cylinders that are buoyant when empty.

If we start with a neutral dive, and we know how buoyant their exposure suit is (see a pattern here yet ) and the buoyancy of the cylinders used then the amount of required ballast is pretty easy to estimate.

The typical 3mm suit is 3-5 lbs positive, and an empth al 80 is +4 lbs in salt water. That means a neutral diver with a 3 mm suit and al 80 needs ~8 lbs of ballast. A stainless steel plate and harness will provide about 6 lbs. and a reg is about -2 lbs.

Many divers using 3mm suits and al 80 dive using a Stainless Plate, harness and reg for ballast.

That same diver using no exposure suit (or a skin which are often barely buoyant) and the same al 80 would be ~4 lbs over weighted.

That same diver using a 3mm suit and steel tank that is ~-2 lbs empty will be about 6 lbs over weighted.

If you stick with a 3mm suit and al 80's and the SS plate is near ideal in warm water.

In a 7mm suit the SS plate is an obvious choice.

Any BC, including a wing, need to met two criteria, 1) Provide enough lift to float your "rig" at the surface with a full cylinder, and 2) be able to compensate for the maximum possible change in buoyancy of the exposure suit. Any exposure suit can lose all the buoyancy it starts with at the surface, but no more than that.

Warm water example:

Rig, Medium Stainless plate &harness,(-6 lbs) reg (-2 lbs) and full al 80,(-2 lbs) total negative of about 10 lbs. To float the rig a wing great than 10 lbs is required

Suit, 3mm, 4-5 lbs positive 10 (rig) > 5 (suit) This diver needs a small wing. 3mm wetsuits and al 80's are *why* we offer 17 lbs wings.

Cold water Example

Rig Medium Stainless plate and harness,(-6) reg (-2) full High pressure 100 Steel tank, (-10 lbs full, -2 empty) total negative -18 lbs.

Suit, 7mm, 18-24 lbs positive. (Need to test that suit!) 24 > 18, buoyancy of the suit dictates minimum required wing capacity.

Torus 26 or LCD 30 wing are reasonable choices.

Same stainless plate for warm and cold, 26 or 30 lbs wing probable, based on buoyancy of the divers suit.

Wings for "Compromise Rigs" are almost always based on the buoyancy of the Cold water suit.

Tobin

 

[eelnoraa]

I do 100% agree with Tobin's suggestions. But I am going to give you a less expansive, IMO equally versatile combo. Maybe Tobin won't agree with me here, but it is what I did and happy with.

1. buy two plates. SS for cold water and Kydex/AL for travel to warm location. If you want STAless setup, DSS implementation is really as good as it gets. For cold water, you can add weight plates to the backplate if necessary. For warm water, I prefer light weight plate because it leave me option to add weight where I needed. I need to add 6-8lb to upper camband to counter my leg heavy physique.

2. buy a good design wing in 30-35lb range. It is large enough for cold water. With wing DSS, Oxycheq, or even Halcyon, their 30lb range wing is still very smaller and streamline. It maybe true a 17-20lb will be better, but I really don't notice much difference myself. I used to have a DSS17lb for warm water. Due to lack of use, I gifted to my cousin who live in tropics. Now I use a 30lb wing for all single tank diving. It works out fine for me.

 

[cool_hardware52]

I do 100% agree with Tobin's suggestions. But I am going to give you a less expansive, IMO equally versatile combo. Maybe Tobin won't agree with me here, but it is what I did and happy with.

1. buy two plates. SS for cold water and Kydex/AL for travel to warm location. If you want STAless setup, DSS implementation is really as good as it gets. For cold water, you can add weight plates to the backplate if necessary. For warm water, I prefer light weight plate because it leave me option to add weight where I needed. I need to add 6-8lb to upper camband to counter my leg heavy physique.

2. buy a good design wing in 30-35lb range. It is large enough for cold water. With wing DSS, Oxycheq, or even Halcyon, their 30lb range wing is still very smaller and streamline. It maybe true a 17-20lb will be better, but I really don't notice much difference myself. I used to have a DSS17lb for warm water. Due to lack of use, I gifted to my cousin who live in tropics. Now I use a 30lb wing for all single tank diving. It works out fine for me.

That's certainly one solution.

It's not at all uncommon for our customers to dive cold water at home, and warm on vacation.

The most common solution is a Stainless Plate and a carefully sized cold water wing. Most use this to good effect.

A few will elect to add a 2nd smaller wing.

Even fewer will eventually add a kydex plate if they are traveling to destinations where the last "hop" is via light aircraft.

Tobin

 

[dmaziuk]

Well that's the part that I don't understand. First of all, I have never dived in fresh water - always salt water. This means more weight. With an empty aluminum tank you said that you "float comfortably at 3-4m". I am assuming that you mean floating at the surface. If you float comfortably at the surface, how do you manage to stay underwater at the end of the dive at 3 m? That is a major problem for me because if I would be weighed like that, I would be shooting up to the surface at the first hint of breathing. Which is why I take a little extra weigh.

No, I meant at the safety stop depth. Our diving well here is just shy of 5 m deep and I can stay down there with empty tank breathing normally.

I think with AL80 and 3mm full suit in salt water and no luggage weight restrictions steel plate should be about perfect. Just carry an SMB or something in case you heed extra lift. Depends on salinity, though: I ended up carrying 4+ kgs of lead on Roatan, that was about twice as much as I expected...

 

[cool_hardware52]

I can stay down there with empty tank breathing normally.

That's a pretty good trick.

Just poking a little fun, I know what you meant.

Tobin