Dive knives and back inflation bcds

[temet vince]

Ok, extreme newbie questions here.

I'm not real impressed with my local dive shop for many reasons, but I've overheard them say 2 things recently to customers that bothered me, one of them being me. But, being a complete newb, I thought that maybe I was wrong, as things in Scuba aren't always that intuitive.

First off, someone was look at buying a dive knife, and the lady told him that he should never sharpen it. ? She said that if he sharpens it, the protective rust coating will break and his knife will rust all over.

Why not just sharpen your knife, and rinse it off with fresh water after the dive and make sure you dry it off really well? Will that not work?

Secondly, I was looking at trying a back inflation BCD, and she said they haven't carried those for 15 years since nobody except tech divers like them. She said that since the air bladder is on your back, you can't suspend vertically underwater.

Huh? I would assume that you would be able to swim horizontally really well, but I don't see how that bladder could keep you from positioning yourself vertically if need be. Am I also wrong here?

The owners of the store have tons of experience and have dived since they were young (they're older now, probably 50's, and still diving). But they look down their noses at new people so bad that I refuse to ask them any questions. What do you all think? Are these just two unintuitive questions, or are the people at the dive shop a little wacky?

 

[soltari675]

I don't know about the dive knife question. Would be interested to know as well.

However I disagree with her about the back inflate BC. I use the Ladyhawk which is a back inflate and I love it. I feel more stable underwater and I can very easily stay vertical if I want. The only complaint I have heard is some people feel it pushes you forward at the surface. I found if I put a couple pounds of weight in the back trim pockets, which I do anyway for trim underwater, and I lean back, I have no problems with getting pushed forward. It's completely a preference thing. But I really enjoy my back inflate over the others. And mine is NOT a tech diving BC. Sounds like the dive shop owner was just showing bias when the customers were asking questions, channeling her own preferences perhaps.

 

[Kenny13]

Secondly, I was looking at trying a back inflation BCD, and she said they haven't carried those for 15 years since nobody except tech divers like them. She said that since the air bladder is on your back, you can't suspend vertically underwater.

I'm not a tech diver and I love my back inflate. Just saying. I find that the back inflate tends to help you get horizontal in the water, buy you can still get yourself in a vertical position if needed.

 

[temet vince]

Yeh, I had done a lot of searching and googling, and there is a lot of discussion about back inflated bcds pushing you forward at the surface. But I couldn't find anything about below the surface, which made me question her integrity about whether she just wanted to sell me something she had in stock.

 

[Ste Wart]

I don't think I've ever owned a dive knife that didn't rust; even straight out the packet.
I've always applied a thin layer of silicone grease on it before diving and rinsed it fresh water afterward. I'd like to say I do this religiously, but I'm fairly slack with cleaning my equipment.

 

[Crush]

The short answer is that you should run away from that shop screaming - their answers were total BS.

First off, someone was look at buying a dive knife, and the lady told him that he should never sharpen it. ? She said that if he sharpens it, the protective rust coating will break and his knife will rust all over.

I have never sharpened my dive knives (plural) because I only use them for diving and the odd time that I have had to use them they did not endure much wear - they are (almost) as sharp as the day I bought them.

That being said, they are made of titanium so they can't rust. A stainless steel knife made for diving can and will eventually rust, so those knives need to be rinsed with fresh water, dried, and oiled. Sharpening a stainless steel knife will not cause it to rust. However, cheap **** knives that are made of non-stainless steel and coated with chrome (or whatever they use) will rust badly if you scrape off the chrome by sharpening.

You should be able to get a good titanium dive knife for $50. Try scubatoys.com or leisurepro.com.

Secondly, I was looking at trying a back inflation BCD, and she said they haven't carried those for 15 years since nobody except tech divers like them. She said that since the air bladder is on your back, you can't suspend vertically underwater.

That is pure BS. I have no problem hovering horizontally or vertically, on the surface or underwater, with my rear-inflate BC or my BP&W. It is all in placing your weights correctly so that you can achieve good trim. I used to experience my rear-inflate BC "pushing" me forward at the surface, but I have since determined the causes of this to be: (1) my weights (34# is lots of lead since I am in cold water) were too far forward, pulling me into a face-down position; and (2) my BC was too loose, allowing it to ride up. Once I re-positioned my weights and tightened the BC (or added a crotch-strap in the case of the BP&W) this problem vanished.

But they look down their noses at new people so bad that I refuse to ask them any questions. What do you all think? Are these just two unintuitive questions, or are the people at the dive shop a little wacky?

I think that they will very soon be victims of internet-based sales, and they will complain bitterly about it. Your LDS should be helpful, answer questions, and be prepared to meet on-line prices or offer other value.

 

[soltari675]

Yeh, I had done a lot of searching and googling, and there is a lot of discussion about back inflated bcds pushing you forward at the surface. But I couldn't find anything about below the surface, which made me question her integrity about whether she just wanted to sell me something she had in stock.

Never had the problem underwater. I find, like mentioned earlier, that it helps me stay horizontal underwater. But I am always able to easily go vertical at any time. I don't even notice the BC most of the time.

 

[Kenny13]

I don't think I've ever owned a dive knife that didn't rust; even straight out the packet.
I've always applied a thin layer of silicone grease on it before diving and rinsed it fresh water afterward. I'd like to say I do this religiously, but I'm fairly slack with cleaning my equipment.

I've heard the same thing about dive knives. I know my son-in-law bought a decent looking stainless steel one and it had surface rust on it after his first dive with it. Wondering if anyone has had any luck with the titanium ones

 

[Kenny13]

Never had the problem underwater. I find, like mentioned earlier, that it helps me stay horizontal underwater. But I am always able to easily go vertical at any time. I don't even notice the BC most of the time.

That's one of the things I like most about my BC. I got the latest Oceanic Excursion and it's just so much more comfortable than the full jacket style BC's that I had to rent in the past. You don't feel confined have much more range of motion should you need it.

 

[soltari675]

I have a titanium dive knife and so far have done 9 dives with it and no rust. I try to dry it off at the end of each day, but I know on half of those I didn't. No problems. I sharpened it the day I got it. But I assumed it was because it was titanium. I imagine the others will eventually. But I don't see sharpening making it worse.