Estimating Weight Needed for New BCD

I'm a newbie, recently PADI Open Water certified. I just picked up a wetsuit (Aqualung SolAfx 7/8mm hooded semi-dry, large) and will pick up a BCD (ScubaPro Knighthawk) next week as well. I have 7mm booties and 4mm gloves as well. I weigh 175lb.

How do I estimate the weights needed for the integrated weight pockets so I can buy the correct units? If I'm off, do I have to buy different units or is there a way to adjust up/down?

Well you fill the pockets with weights.
do you know what you wore for the OW course and how much weight you had?

i did my OW course with a 7/5mm, no boots hood or gloves and carried 21 lbs of weight.
now i dive with a 5/4mm suit and use 15 lbs of weight, would be 18 but my bcd is a bit heavier than others so minus another 3 lbs.

for a thick suit like that i would presume 21 lbs.

Welcome to the board.
Unfortunately, there is no simple answer because the weight needed varies widely between individuals, exposure suits, tank sizes and materials and water conditions. Depending on your body makeup, your weight needs can vary widely. If you are a 175lb male body builder you will need less than if you are a 175 lb fluffy female. Wetsuits vary a good bit as well, a new brand X will require a different amount than a new brand Y and both of them will require less as they get used. If you dive both fresh and salt water your weight needs will vary by 5 to 12 lbs . Even your experience comes into play. A very experienced diver will require less than a new diver. So, exactly how much is not something we are going to be able to give you an accurate amount on.

IMO, more important than the exact amount is the values you buy. For example, if you need 30 lbs, you could buy 2- 10lb and 2- 5lb weights, the trouble is as you get experience you will most likely need to drop some of the weight or if you swap to a lighter wetsuit in the summer you are stuck with a limited number of choices, none of which are very good. A much better approach is to buy a varity of sizes so you can swap around as your needs change. With all that said, my off hand guess is you will need somewhere in the 25 to 35 lb range. It were me, I would up that to 40 lbs and buy a wide variety of sizes in pairs. Maybe 4 x 5 lbs, 2x 4lbs, 2x 3lbs, 2 x2 lbs and 2x 1lbs. With that variety you can match your weight needs to within 1 lb anywhere from the full 40 lbs to 2 lbs. Odds are you will not need that much but weights last forever, you will want the ability to vary your weights over time and sooner or later some buddy is going to need a few more pounds than he has...which by the way brings up another subject....mark them so you can get them back from the slacker.

As a recently cert'd diver, I can feel your pain on this one. I have 36lbs of lead (mostly in 4s and 5s, I believe) and ended up using 32lbs of it with my 7mm john during the OW class (although I have about 15 lbs on you), just to be negative enough to feel comfortable with mask clearing and all that. My goal is to get it down to 25 or so, once I start doing more and more real dives.

I can tell you that your 7/8 hooded semi-dry is a lot more buoyant than a 7 mil wet suit. As noted, you will need to do a proper weight check wearing the gear you will use in the waters in which you dive, each trip, until you accumulate enough data to simply reference your log book for the proper weight in different conditions and with different equipment. If you are buying weights, I would acquire about 42 pounds ( more than you will need, probably) in these denominations: two 5 pounders, four 4 pounders, four 3 pounders, and two 2 pounders. Anything bigger than a 5 pound weight may not fit in integrated weight pockets. If there are back pockets in your bc, you will want to put a 2 or 3 on each side for better trim. With this combination you can weight yourself by 1 pound increments everywhere from 2 pounds to 42 pounds. As you vary your weight requirements due to conditions and equipment variables, you will always be able to weight your self properly.
DivemasterDennis

Great advice there guys - many thanks. Looks like I'll be making my Local Dive Shop happy next week when I pick up my BCD and a stack of weights!

I would not buy any lead at all yet. Unless they have a pool where you can do a weight check with all your new gear as a starting point. Lead is expensive and you could save yourself a bunch of money if you went with a Back plate and wing over the knighthawk. I'm thinking it has a min of 4-5 lbs inherent buoyancy alone. Get a steel plate, wing, and simple harness for under $400 and save buying 8-10 lbs of lead at the same time. For coldwater diving you are going to want to get some of that weight out of the BC and on a belt anyway. If carrying more than 12 lb I tell my students to distribute it and not put it all in one system like a weight integrated BC. If you do end up needing say 30 lbs where are you going to put it?


Ok 5 in each trim pocket. 10 in each integrated pocket. If you need to ditch for some reason at depth or the pocket would fall out are you going to be able to control your ascent with a 1/3rd of your ballast gone? If you drop both of them your fin tips may clear the water! Integrated weights are ok for warm water diving where you do not need much weight. For cold water my experience is they suck. They make the BC a beast to put on and take off.

I got into the habit of wearing a belt when diving dry and using an integrated jacket BC. I needed 28 lbs so I had 5 in each trim pocket, 6 in each integrated pocket, and 6 on the belt with a steel tank. That way if I needed to I could drop the 6 with the belt and still control my ascent. And those pockets are damn expensive to replace. A belt is cheap.

You could rent a weight belt the first time to see how much weight you need. The shop can also give you a good starting point of what you might need based on your body type and exposure protection. After you figure it out, then buy the weight belt and the weights you need.

Smaller weights would be better so you can move some around as you adjust your trim - 2lbs, 3 lbs and 5lbs - at least two of each weight so you can place them evenly. Maybe even one or two 1lbs, but that can come later too if you need them.

I second Jim's suggestion to use a backplate and wing instead of a jacket style. I switched after 9 years to a bp & wing last summer and love it. The trim is so much easier and streamlined and there's no extra buoyant material like a jacket. I only need to wear 8 lbs with my AL backplate, weighted Single Tank Adapter and AL tank; no weight if I were to wear a steel bp and/or tank. Many people end up switching to a bp & w, so it's a good idea to just start that way...

Another thought: What is the situation where you are going to be diving, in terms of weight/tank rental?

If you're shore diving with your own gear, then I suppose you'd want all your weights right away.

So far I've mostly dived from a commercial boat, and I rent tanks. Along with that tank rental comes free weights, so I don't need to have my own. That said, I do carry four individual 1# weights with me, because I have found that oftentimes boats don't have them, and many times, they run out of 2# weights. So then I'm stuck with only 3# or heavier chunks, which doesn't work well for me. With my four 1# weights I can make whatever they have work.

You may not need or want to go down to 1#, if you are diving in colder water. Maybe then tweaking by 2# or more would be plenty.

Blue Sparkle

For starters.

10% body weight + (3-5 lbs) salt water. May want start little heavy 2 lbs since better little heavy than little light.