Travel BC vs Std BC for regular diving?

[Mortis65]

Hi to all the experts out there.

I appologize for the length of the question, but I want to ensure that my assumptions are correct. (Yes I am an engineer. )

I'm new to diving, and I've been doing my research on gear. I am not asking what BC to get, rather, I am trying to understand some of the reasoning that some have offered with regards to using a lighter weight, lighter lift Travel BC vs a more conventional BC for local (ie cold fresh water) diving. Just for reference, I am in Colorado, and I hope to do some lake and reservoir diving, in addition to vacation diving in nice warm island waters.

Here is my understandsing so far. Please correct me if I am wrong on any of my assumptions.

I will assume for this discussion that I will be using a weight belt (I do plan to travel without weights).

At the surface, fully loaded (full tank), one should be neutral with a lung full of air, and an empty BC. Lift capacity of the BC should be an non issue. We then add a couple of lbs to account for the empty tank at the end of the dive.

So, at the start of the dive, I'm maybe 2-4 lbs negative. At the end of the dive, I should be neutral again.

With just my skin, in warm fresh water, I'm diving with 8 lbs. (I'm 190 lbs, male).

Of course, if I'm in cold water, I'd be wearing a wet suit (dry suit not in scope for me at this point). If it is a 7mm suit, the math suggests that I should be wearing about 22-24 lbs to be neutral at the end of the dive. (I'm thinking 12 - 14 lbs just for the suit.)

Now, with wetsuit compression at depth, I know that I will loose some of the wetsuit boyancy, which at 60 ft could be as much as 1/2, which suggests to me, that I will need to compensate with 6 to 8 lbs of lift in the BC to bring be neutral again.

SO:

The reading that I've done shows that a Travel BC seems to always offer 20 -25 lbs of lift at the low end. This suggests that I can take 5 lbs of dead weight (other gear) and still have a nice saftey margin.

My question, after all of this is, why would I want a fully loaded BC that has 30-35 lbs of lift, vs a Travel BC that may have less lift, but still offers all the lift I 'think' I need?

Thanks

Mortis.

 

[dashark]

When I dive I am always travelling in one way or another. either a car , a boat or a plane or all three. I traded in my first "big" bc a couple of years ago because it was just too bulky. Even for every day diving, but, especially for international travel.
I had the same question at the time. I weighed about as much as you did, maybe 6-7 lbs more at one point.
I started using a seaquest passport for both local cold water diving and the tropics. It i very conpact and has it's own built in mesh bag that it folds into when you store it.
i have not noticed any problems in the change while diving. If anything, I am more streamlined in the water and the bc doesn't seem to shift as much as the bigger one did. I am about 26 lbs lighter now and still use only the one bc.
the beauty of it is all of my gear, wetsuit and all , fits in one large mesh backpack. I am grateful for the more compact bc whether I am "travelling" or not. Even in the water it feels like I am carrying less.
That is just my experience. This is scubaboard, though, there are many more to come.

 

[RJP]

My question, after all of this is, why would I want a fully loaded BC that has 30-35 lbs of lift, vs a Travel BC that may have less lift, but still offers all the lift I 'think' I need?

Do all the figuring and comparing you want. Identify your top choice "fully loaded BC" and your top choice "travel BC." Then, just buy the travel BC and use it for all your diving.



Seriously.

 

[capeellyn]

Hi,
I'm new here, but have sold dive gear since 2000 and been diving for 9 years - mostly in the cold waters of Northern California. As a Divemaster I can't help but come from the point of view that if you ever needed to help a fellow diver in need while in your 7mm suits, you may not have the proper amount of lift to keep both of your heads above water. I agree with Dashark that Seaquest's Passport BC is an excellent choice for warm water travel (the mesh bag that holds it can be rolled up and used as a lumbar pad while you dive) but keep in mind he lives in LA. If you think you'll mostly dive in warm water - go for the Passport and rent a nice cold water BC from a reputable shop when you go locally. But if you think you'll do a lot of cold water diving also, and could get into a drysuit in the future - get both. Full-size BCs have more pocket space, can hold ballast weight in pockets behind your ribs and use an integrated weight system. They're more expensive, but worth it in my mind. The Passport is pretty cheap - only a couple hundred bucks, barely what you'll pay for airfare to a good site. Remember also, that if you buy most large name brands on-line the products do not come with a warranty.
Those are my 2cents on buying new gear.
Dive safe!
- Ellyn

 

[SharkDZ]

I dive with a Mares Icon full-time. My first BC, a Sherwood Magnum, is a great BC, but was a bit bulky for my tastes. I tried on an Icon and fell in love with the features and pack-ability. It "folds" neatly in a bundle for transport, etc. My intent was to use it while in Kona for a week, but it's so comfortable that I use it all the time in my home SoCal waters. While in the pool I use 8lbs. on a belt. In Kona I used 12lbs. in the pouches with a 3mm full, while at home I use between 18-24lbs., depending on the 7mm full I'm wearing. Oh, and it lacks a velcro waistband and it is a back inflate. I'm not very fond of velcro, either. All in all a great BC, but there is only one pocket, if you are in to pockets. So, take a look at the Mares Icon.

 

[evil_xander]

Go with the 'travel BC' and make it a BP/W, so if you need more lift just add a bigger wing, thus rendering the cost of having two BC's less.

 

[Sadamune]

make it a BP/W...

I concur, a backplate/wing system is the best travel rig. It is inherently modular and very easy to pack, as the backplate is already very flat and the wing can be rolled up. Weight shouldn't be an issue, but an aluminium backplate can be substituted for a stainless one. Simple, versatile, robust, modular...perfect.

Sadamune

 

[dashark]

Ellyn brings up a good point about extra pockets. The one thing I miss about my larger bs was the ability to add small amounts of weight to different areas of the bc.
I forgot to mention the BP/W.... that makes the most sense......Enjoy!

 

[DPJ]

Hi,
I'm new here, but have sold dive gear since 2000 and been diving for 9 years - mostly in the cold waters of Northern California. As a Divemaster I can't help but come from the point of view that if you ever needed to help a fellow diver in need while in your 7mm suits, you may not have the proper amount of lift to keep both of your heads above water. I agree with Dashark that Seaquest's Passport BC is an excellent choice for warm water travel (the mesh bag that holds it can be rolled up and used as a lumbar pad while you dive) but keep in mind he lives in LA. If you think you'll mostly dive in warm water - go for the Passport and rent a nice cold water BC from a reputable shop when you go locally. But if you think you'll do a lot of cold water diving also, and could get into a drysuit in the future - get both. Full-size BCs have more pocket space, can hold ballast weight in pockets behind your ribs and use an integrated weight system. They're more expensive, but worth it in my mind. The Passport is pretty cheap - only a couple hundred bucks, barely what you'll pay for airfare to a good site. Remember also, that if you buy most large name brands on-line the products do not come with a warranty.
Those are my 2cents on buying new gear.
Dive safe!
- Ellyn

I would also consider back plate and wing.

In regards to warranty, some sites sell grey market gear with out a warranty. Others like SubaToys and Diverite Express (and many more) have full warranties.

 

[muddiver]

I went with the Dive Rite rig because you can change out the lift bladder. I originally bought the standard size cold water bladder (wings) and it worked really well for the cold California water diving. Recently I started going to Hawaii a lot, so I purchased their travel wings and it saved a lot of room in my dive bag I carry on the airlines. A typical vest BC would never fit in any reasonably sized bag like the travel wings and teh Dive Rite harness.

If you ever plan to get a dry suit, you must have the cold water lift. Dry suits require a large amount of weight to compensate for the dry suit. There is also the possible danger of the dry suit leaking or loosing air (like maybe a stuck exhaust valve) when you will need the BC to overcome the negitive buoyancy of the weight you are carrying.

I am still out on the whole back plate thing. If you ever plan to dive with more than one cylinder on your back than get one, otherwise it is an added expense that is hard to reasonably justify.

Also consider what you usually carry when you dive. I look like a walking garage sale because I will carry a light, a camera w/ strobe, a surface "hey I'm over here" kit and for local dives a pony bottle. With all the extra crap it is hard to get the buoyancy right at depth with out a good margin of lift from your BC. For travel I forgo a lot of the gear because in Hawaii the water is so clear you don't need most of it (plus the camara housing I have right now is positively buoyant).

It sounds like you have the buoyancy thing figured out. It is still not an exact science because manufacturers of SCUBA accessories do not provide the buoyancy charactoristics of their equipment on the box they come in. Buoyancy is not defined by the physical weight of an object, as you know, but by the volume of water displaced by the object in relation to its weight. If you are real anal about your trim with certain gear you could do some displacement testing and figure the buoyancy charactoristics of everything you might carry. But, this is RECREATIONAL diving so except for us in-gan-neers, I doubt that anyone would bother going to that extreme.

Humm... wouldn't that make you a true tech/DIR diver if you figured the buoyancy of all your gear configurations and logged them for furture reference?

And last but not least "Gray market gear"?