So Confused About Plate Weighting, Wing Size, etc.

So, I think I'm getting close here. Last night, I tried a Transplate harness along with a DiveRite SS plate and rec wing in the pool. With a FULL tank (couldn't breathe it down much), I was neutral (eye level at the surface) with a 3.5 mm full wetsuit. No weight.

Here is where I get confused. First, because the tank is full, it's heavier than it will be late in the dive, so I assume I'll need to add weight for that. Plus (this isn't confusing), my eventual 5mm suit will also be more buoyant. When weighting at the beginning of previous dives, though, again, we were dealing with a full tank, and I had 12 lbs in the ocean and 6 lbs in the fresh water (where I was neutral). So, given that, if my tank is ending at 500psi, why wouldn't I be then potentially uncontrollably be floating to the surface as I got close?

So here are my questions...

1. Do all 5mm suits have generally close buoyancy amounts, or do they vary widely?
2. I'd like to add weight to the plate or near the top of my body, because I have heard that having a lot of weight on the belt will make it harder to trim easily.
3. If I do add to the plate (let's say those weight plates that can attach to a DSS plate), what if I need to ditch weights? Are there ditchable weights not in weight belt form?
4. How do you BP/W users divide your weights? I'm deciding between the Transplate harness, DiveRite SS plate, and Venture wing; and Tobin's DSS system. I like how Tobin's has the rubber thing for the single tank and the possible weight plates, but for travel, may need some type of other weighting system.
5. How the heck do I determine the weight I need? With a full tank, if I'm neutral, do I simply add the difference in buoyancy due to the empty tank, and add that to my weighting?

Thanks so much. I'm sorry to be such a newb.

One clarification...On my previous dives, I was using a 5mm full suit and a jacket BC.

wow, so many variables!
1. Im 6'4 with a 52 inch chest, lets say we both buy 5 mil wetsuits, whos do you think will float more mine or yours? The more neoprene, the more weight needed
2. In a single, I like the weight up high, in doubles, I dont use any weight (wish I did down low though) I made a 7 (9?) lb chanel weight that I bolted to the top of my back plate. You can get XS scuba weight pockets you mount to the tank straps, you can get weighted single tank adapters, there are many ways to skin the cat. But I wouldn't spend much (any) money untill you get your setup and see how you trim out first. Do you rent aluminum tanks, do you own a steel tank? These will greatly effect your trim.
3. the bolt on weight plates are not ditchable, you would want enough ditchable weight so that you can swim your gear up from depth with your wetsuit fully compressed, with no air in your bc and a full tank of air (beginning of dive when you are the heaviest). You can get integrated weight pockets that go on your waist belt.
4.single: single 119, now 6lb (?) halcyon weighted single tank adapter, and a weight belt (no idea how much weight because it has been years since I dove a single tank anywhere but a pool (last weekend) or in water warm enough to not require wetsuit. Doubles: no weight needed.
Used to have 7or9 lb weight up at the top of my DR plate, and I was over weighted with 10lbs on a weight belt.
5. What type/size tank? an al80 will go from be 5lbs lighter at end of dive. Best bet is to do a dive, slightly over weighted (get in water, normal breath, no air in bc, float at eye level, exhale and you should descend) by a few lbs, do a dive, now your wetsuit is nice and wet, at 10feet of depth with your buddy close blow down your tank to 500 psi, you should be neutral with no air in your bc, if you need air in your bc, hand off a few lbs of lead to your buddy, dump air, repeat test. If you are too light, pick up a rock...

ok, if you are going from a big 'ol vest to a simple SS backplate you should be able to drop about 5-6 lbs. I would recommend against the DR Rec wing, its too big for a single tank and not a great design for doubles.

Yeah...I wasn't going to buy the rec wing...that's what they had on hand. I might get the Venture, if I go with the DR stuff. So it looks like I just have to test and won't get all this sorted until I'm actually in the conditions I need to be in. It looks like I could easily get away with the 26 lb Torus for singles if I go with the DSS stuff.

I'm assuming any ditchable weight will have to be on a belt somehow. I have a regular weight belt with pockets (very cheap thing).

Lenmonster:

1. Do all 5mm suits have generally close buoyancy amounts, or do they vary widely?

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Not all neo is the same density. High density rubbers are less buoyant, and compress less at depth. The size of the diver, the cut of the suit, the density of the rubber, and how wel used the suit is all impact the initial buoyancy of the suit. I expect a "5mm" "full suit" to be in the range of 12-18 lbs for a diver of normal stature.

Lenmonster:

2. I'd like to add weight to the plate or near the top of my body, because I have heard that having a lot of weight on the belt will make it harder to trim easily.

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This may or may not be required. With SS plate and Steel tank you may have all the weight up high (over your lungs) that you need. OTOH, if you are using a buoyant tank you may need a bit more ballast higher on your body. This can be determined only by trial an error.

Lenmonster:

3. If I do add to the plate (let's say those weight plates that can attach to a DSS plate), what if I need to ditch weights? Are there ditchable weights not in weight belt form?

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Way to early to think about weight plates. You need to first determine your ideal total weighting. In a 5 mm suit and steel tank you may not even need 8 lbs of additional ballast. Lets say your suit is + 14 lbs and you are using typical steel tank that's about -2 when empty. With a SS plate and harness (-6), regulator (-2) and steel tank your rig will provide about 10 lbs of ballast. That leaves about 4 lbs in a belt. If you are using a al 80 (+4 empty) you would need about 10 lbs in a belt. Even in this case using 8 lbs weight plates + a 2 lbs in a belt is not ideal.

Lenmonster:

4. How do you BP/W users divide your weights? I'm deciding between the Transplate harness, DiveRite SS plate, and Venture wing; and Tobin's DSS system. I like how Tobin's has the rubber thing for the single tank and the possible weight plates, but for travel, may need some type of other weighting system.
5. How the heck do I determine the weight I need? With a full tank, if I'm neutral, do I simply add the difference in buoyancy due to the empty tank, and add that to my weighting?

Thanks so much. I'm sorry to be such a newb.

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I recommend you determine the buoyancy of your wetsuit. Roll it up and throw in a pool (or tub) and add weight until it just sinks, then weigh the bag o lead.

Assuming you, in swim trunks, are close to neutral, the buoyancy of your wetsuit is close to the amount of ballast you want to have with an empty tank.

The steps in the process are:

Determine the buoyancy of your exposure suit. This, and the tank used will set the lower limit for wing size.

Get your total weighting dialed in. 500 psi at 15 ft with no gas in your wing, or neutral at the surface with a full tank and no gas in your wing.

Trim weighting. It's not useful to try and get trimmed until after you get your total weighting nailed down.

I'm happy to help. Give me call tomorrow if you like.

Tobin

Have you sent a PM to Tobin at DSS (www.deepseasupply.com)? He goes by the user name cool_hardware52 on SB, and by Tobin George on The Dive Matrix - Scuba Diving Forums, Articles & Travel Directory He's far and away the most accessible manufacturer of this stuff on any of the major boards.

He'll take the time to speak with you directly, evaluate the system that is best for you based on the tank you're diving and the exposure suit you're using, and he'll steer you straight.

You should PM him.

---
Ken

Tobin...

I'll call you tomorrow. Thanks...I know you went over a lot of this via email, too, but I didn't think you'd be working on a Sunday night! ;-) Plus, you've already sent me like 3 emails trying to explain everything (I'm not normally a dense person, but this stuff takes some getting used to), and I don't want to waste too much of your time. But a phone call will probably be way easier than an email chain.

As Tobin mentioned, I wouldn't look at weight plates yet. A couple of XS Scuba weight pockets strategically placed will let you try LOTS of configuration possibilities + let you travel and use the lead found there. However getting your rig from DSS (big improvement over DR - I've used both) will give you the possibility of adding weight plates in the future if you decide to do so.

Aloha, Tim

Cool. Those pockets look really useful. It looks like you can slide them anywhere on the shoulder straps or waist strap of the harness. And I like not having to pack that extra weight (something tells me ultimately I won't need as much as the plates, as I'm not that heavy).