Aluminum or SS backplate?

[amc717]

I'm not really sure whether this question belongs in this category, please feel free to transfer it to the proper category.

Just wanted to find out, is it advisable to get a lighter Aluminum backplate or a heavier SS backplate (i.e. to eliminate that use of a weight belt or weights)?

The question arose from my use of an aluminum backplate. I tried it in the pool and I had a hard time sinking. If I had difficulty sinking in the pool, definitely I'll have a bigger problem in the sea. I switched to SS backplate, a little heavy but doable.

Another question is, what if you need to ditch your weight? In open water class, we were taught to ditch our weights and tanks in cases of emergency. Wouldn't a heavier SS backplate cause a problem?

Hope you could help. Thanks.

[gfisher4792]

Choices of AL or SS typically depends on the water you're diving in. Cold water for SS (because thicker exposure protection means more weight needed) and Warm water for AL (not as much protection needed). In my case, I dive mostly coldwater with 7mm, which takes a lot (28 lbs) of weight. With my BP (and STA) I transfer 8 pounds onto my back, which still leaves 20 on my waist. I'm still configuring it, and may chnage STA to transfer more to my back.

There are differing opinions as far as ditching weight (on this board? No!). In my case, if I did ditch weight, losing 20 lbs will still shoot me to the surface. There are divers who have all their weight non ditchable, with the thinking that if you can't kick up and rise to the surface, you're overweighted. Plus, some people just don't like the thought of experience an uncontrolled ascent by ditching.

BTW, I hope you meant that you were taught to ditch your weights and NOT your tanks in an emergency.

[jonnythan]

The question rests simply on how much ditchable lead you need to wear.

If you can wear the 6-lb SS plate and still have enough ditchable lead to dive safely, then wear the SS plate. If not, wear the Al plate.

[amc717]

You are correct, I was talking about ditching the weight belt. And the tank, if need be, at the surface.

I dive mostly the warm waters of Southeast Asia.

[jonnythan]

After rereading your post, I need to make something a little more clear. With an Al plate, you'll need to wear about 4-5 pounds more lead to achieve the same buoyancy as with a SS plate.

Your sinking issue is a problem with total buoyancy, not with which plate you have on. Al plate + 4 pounds of lead will be the same as a SS plate with no lead.

BTW, you're kinda supposed to have trouble sinking. Find out exactly how much weight you need to wear by breathing a tank down to a few hundred psi. Use trial and error to determine exactly how much weight you need to enable yourself to sink by exhaling under those conditions.

[amc717]

At present, I am using a SS backplate and no additional weight belt. With my old bc, a SP Classic, I use 4lbs., a 2 lb wt connected to the back of my BC and another 2lb wt. on my belt.
When I used the Al in the pool, my tank was down to 500psi.

[jonnythan]

1) I don't know what kind/how many tanks you have on your back, but make sure you can swim them up from depth with a totally empty wing if you're diving without ditchable weight.

2) If you have trouble staying down with an Al plate by itself, might want to stick with the Al plate and just add a pound or two of weight somewhere. Tank band, weight belt, waist belt, etc. If you're wearing a 6lb plate but only need 4lb of weight, the Al makes more sense.

[amc717]

Thanks for the input. Will try it out over the weekend. Happy diving!

[teknitroxdiver]

If you (like me) don't want a weight belt, but are in between the aluminum weight and the SS weight, you could use a heavier STA or maybe a small chunk of lead in the channel of the BP.