AL Backplate or 3mm Wetsuit

[Mike126]

I am a recent (and very happy) convert to the dark side (BPW)! In November I bought a DSS SS backplate and 26# wing from Tobin. My primary diving is local quarry dives with a 7mm wetsuit so with Tobin's help I sized my BPW according to that. This summer we are taking a family vacation to Turks and Caicos and I was going to do a couple of days of diving while there. The SS BP will likely be too much weight without a wetsuit to compensate. I was thinking I would buy a 3mm full wetsuit and use my SS BP. Based on my calculations and using the wing calculator on the forum site, if I dive with AL80 and a 3mm wetsuit I should be about 2 pounds positive. I would wear 2 pounds on my belt to get balanced.

The other option is to buy an AL BP and dive without a wetsuit. If I go that route I would be about 1.5# negative. This assumes the AL BP is about 1.5# negative. I'm not sure that is a correct assumption.

Since I don't get many opportunities to dive in the tropics I can't justify the cost of a wetsuit and AL BP.

The advantage with the 3mm wetsuit is I will definately stay warmer and as I get older I feel like I get cold a little easier.

What would you recommend?

Thanks!

 

[halocline]

I'm not sure how you're arriving at your figures, because an AL80 is 4.4 lbs positive empty, and a steel backplate provides about 5-6lbs ballast, basically offsetting the buoyancy of the tank itself. I can't imagine being significantly overweighted with just a steel plate and AL80, even without any wetsuit. But, maybe you're a negative person...hehe

Anyhow, I would not buy a wetsuit just for this trip, but I would mention that most divers in the caribbean do get cold with no suit after a while, and even when the water's in the low 80s I'm more comfy in a 3mil or shorty. And tropical diving can become pretty addictive, so you might end up using it many more times. Shorty suits are usually pretty cheap, easy to fit, easy to pack, and not too positive.

OTOH, an AL plate is useful, I use mine quite a bit, for steel tanks and doubles. The only thing in your case is that your wing fits perfectly on the DSS plates and the best option would be the kydex DSS plate which is not cheap.

 

[Mike126]

I'm not sure how you're arriving at your figures, because an AL80 is 4.4 lbs positive empty, and a steel backplate provides about 5-6lbs ballast, basically offsetting the buoyancy of the tank itself. I can't imagine being significantly overweighted with just a steel plate and AL80, even without any wetsuit. But, maybe you're a negative person...hehe

Anyhow, I would not buy a wetsuit just for this trip, but I would mention that most divers in the caribbean do get cold with no suit after a while, and even when the water's in the low 80s I'm more comfy in a 3mil or shorty. And tropical diving can become pretty addictive, so you might end up using it many more times. Shorty suits are usually pretty cheap, easy to fit, easy to pack, and not too positive.

OTOH, an AL plate is useful, I use mine quite a bit, for steel tanks and doubles. The only thing in your case is that your wing fits perfectly on the DSS plates and the best option would be the kydex DSS plate which is not cheap.

My numbers for the AL80 were based on the Bouyancy Calculator - Full Tank = -1.6#, empty = 2.8#, End of dive = 2.4#

Are those correct or am I not reading this correctly?

The shorty would definately be a better option for sizing etc. I was just concerned that a full suit would give me a few more pounds of buoyancy.



Thanks

 

[Insta-Gator]

Mike, in salt water I dive a 3mm jumpsuit, 6# Apeks SS PB, 25# wing, AL80, I carry NO lead and my buoyancy is perfect. Don't use "EMPTY" AL80 figures. You won't bleed it dry. Figure the tank will be ~3# positive, but if you use an octo reg set, it will be ~3 negative (mine is) so it all balances out. I can hold trim in as little as 7' at the end of a dive. YMMV, but I recommend you try the first dive without any extra lead.

 

[tursiops]

Sounds to me like the OP did not take the extra buoyancy (about 3%) of salt water into account.

 

[Mike126]

Sounds to me like the OP did not take the extra buoyancy (about 3%) of salt water into account.

Good point I did not take that into consideration.

 

[rongoodman]

Unless your trip is at a much warmer season than mine was(April, I think), I'd be taking the 5mm suit.

 

[Mike126]

Unless your trip is at a much warmer season than mine was(April, I think), I'd be taking the 5mm suit.

I hope it will be. We are going the last week in June.

 

[ams511]

The decision to purchase (or rent) a 3 mil wetsuit should be based on the conditions and how cold you get while diving, NOT the weight of the backplate. If you are short on funds then I would just dive the steel backplate. It is not the end of the world if you are a pound or two overweighted for a dive.

 

[Pullmyfinger]

The decision to purchase (or rent) a 3 mil wetsuit should be based on the conditions and how cold you get while diving, NOT the weight of the backplate. If you are short on funds then I would just dive the steel backplate. It is not the end of the world if you are a pound or two overweighted for a dive.

This. ^