Disadvantages to sidemount?

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Originally Posted by stairman

Wow,thanks for all the good info.Yes shell have to do the class on backgas for sure,since sidemount is considered a specialty.Two 40s would sure be light but penetration on 6ths would be nil.Maybe instructors allow 3rds for tiny tanks since the main reason for 1/6th penetration is to keep out of deco.

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I'll tell you what's really really nice, strapping on a set of steel 51's (or 53's can't remember exactly). They are about the same size as AL40's but they are negative, and small small small...

I use them in OW diving, specially on cattle boats. Lots of air, great for photography, and I just clip in and go. Once I'm back on the boat, I just pull my tanks off, and keep my harness on. This way I'm not fighting with the other crowd that's getting their poodle jacket BC's on. When they drop the ladder, I grab my tanks, clip them in and go. Takes me about 30 seconds. You will tend to draw a crowd though lol.

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Originally Posted by stairman

Wow,thanks for all the good info.Yes shell have to do the class on backgas for sure,since sidemount is considered a specialty.Two 40s would sure be light but penetration on 6ths would be nil.Maybe instructors allow 3rds for tiny tanks since the main reason for 1/6th penetration is to keep out of deco.

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Russell is right about tank size, but you can get a waiver to use sidemount in a cavern/cave class, if the instructor is also a sidemount instructor.

At least back when I started I remember 72cuft being the minumum tank size (2x 72 cu ft I think for apprentice/full) for cave class. I guess there still are 72's around but I wouldn't want to be standing anywhere near the fill station. ;-)

For that reason and just usable gas volumes I'd think LP85s probably the smallest reasonable tank. I guess there are HP80's which are just tiny and cute but I've never heard of them actually being used by anyone. They are short enough maybe they'd make good sidemount tanks. :lol:

HP100s are the same size as LP85s but are a little more negative in the water. For sidemount I think most people prefer the 85s for bouyancy characteristics (thou AL80 with a 1 lb weight near the bottom is nice also).

In backmount tank bouyancy characteristics plus or minus a pound or two are insignificant but in sidemount it's a big deal. I don't think many people starting in cave training should want that kind of headache. For backmount the HP100s are far better tanks then the LP85s just because they can be legally filled to 100cuft and the bouyancy and surface weight are so nearly the same.

Er... ya. What Slüdge said. ;-)

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Originally Posted by OFG-1

The main disadvantage that I have is trying to get tank bungees to match my pink fins. I mean, no one has pink bungee anywhere,

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Here ya go pal, you will just have to import it.
"15 metres 6mm full colour pink - £20.25"
http://www.jimmygreen.co.uk/chandler...shock_cord.htm

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Originally Posted by OFG-1

The main disadvantage that I have is trying to get tank bungees to match my pink fins. I mean, no one has pink bungee anywhere,

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I also have a complete roll of pink harness webbing for ya if you're so inclined to match. Hell, I'll even throw in yellow webbing for the crotch strap.

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Originally Posted by stairman

Yes shell have to do the class on backgas for sure,since sidemount is considered a specialty.

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Not exactly. I met a couple from Tampa at the DO last year. They did (were still doing some) all their cave training in SM from the get go. They were an older couple (late 40s-early 50s) and I figure they decided BM was too heavy for them.

Before I met them, I thought that SM was a specialty. It looks like it doesn't have to be. For someone that has only dove single tanks before, I don't think it would be much harder to go for SM instead of BM from the get go. There is a learning curve with doubles anyhow. Plus, trim and valve drills are always an issue with new BM divers. Two things that appears to be easier in SM (from what people are saying here).

It's a different stories for tech diver switching to cave (like I did) since I was already comfortable in BM. It would have made no sense to me to do my cave training in SM.

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Originally Posted by Omicron

Rennaker's website has (had?) some decent stuff on it. He used to have a whole section on converting a Transpac and converting a jacket BC to a sidemount setup, but I can't seem to find it now. It was really well done, there were parts lists and everything.

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Well I found it but no images. Makes it hard to understand

http://web.archive.org/web/200412200...sidemount.html

From what I have seen, some instructors will teach you through full cave in SM gear.

That said you probably won't be issued a SM card because you didn't take a SM class. That's not to say you can't learn all the SM tricks later and with a good mentor be a good SM diver but make no mistake, just because you went cavern through full in SM gear does not a SM diver make.

Can you go SM diving W/O a SM card...of course you can. Just like you can use a DPV in LR or JB W/O a DPV card. But I took a class to learn the tricks from the best, Brian Kakuk. He was in town, had the time, I had the time so we did a class.

For instance, anybody that did these skills during their cavern through full cave please chime in. Here are only three examples of skills I was required to do in my SM class.

In the water, find a nice flat rock and:
1) Stand on your head, flood & clear your mask.
2) Stand on your head, flood your mask, remove and replace one tank, clear mask.
3) Stand on your head, flood mask, remove both tanks simultaneously, replace both tanks, clear mask.

You say, those are rediculous skills, why would anybody need to know how to do that? Well, when you use sm for "some" of the reasons it was intented for you often take one or both tanks off, you could have a tank off, going head first down a rather tight chimney and dislodge your mask.

There are many more skills that I learned that simply aren't covered in traditional cavern through full cave classes, with or without sm gear.

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Originally Posted by mmcauliffe

From what I have seen, some instructors will teach you through full cave in SM gear.

That said you probably won't be issued a SM card because you didn't take a SM class. That's not to say you can't learn all the SM tricks later and with a good mentor be a good SM diver but make no mistake, just because you went cavern through full in SM gear does not a SM diver make.

Can you go SM diving W/O a SM card...of course you can. Just like you can use a DPV in LR or JB W/O a DPV card. But I took a class to learn the tricks from the best, Brian Kakuk. He was in town, had the time, I had the time so we did a class.

For instance, anybody that did these skills during their cavern through full cave please chime in. Here are only three examples of skills I was required to do in my SM class.

In the water, find a nice flat rock and:
1) Stand on your head, flood & clear your mask.
2) Stand on your head, flood your mask, remove and replace one tank, clear mask.
3) Stand on your head, flood mask, remove both tanks simultaneously, replace both tanks, clear mask.

You say, those are rediculous skills, why would anybody need to know how to do that? Well, when you use sm for "some" of the reasons it was intented for you often take one or both tanks off, you could have a tank off, going head first down a rather tight chimney and dislodge your mask.

There are many more skills that I learned that simply aren't covered in traditional cavern through full cave classes, with or without sm gear.

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Having done a few SM dives with Brian Kakuk, I have nothing but good things to say about his skills. He is one hell of a SM cave diver, and a good friend as well. A finer SM instructor I do not personally know.

By the way, Brian wrote the IANTD manual for Sidemount / nomount.

Happy Diving...