opinions for size of tank for recreational sidemount diving in coldwater

[rddvet]

The solution for me was to add a Xdeep double central weight pouch to my backstrap.

Absolutely the original reason I went for a stealth was ease of adding weight from their stock spine weight pockets to the additional weight pockets that come with the unit, to the option to buy the double weight pockets. Luckily I've never needed more weight than I can stick in the stock weight pouches.

The big issue is the OP has the SMS75. It has less options for weight attachment.

I have an SMS100 and use the weight plate. I don't know if that will fit on the 75. I'd look into it, and then you have all the options in the world.

I think boat diving is much easier with al80s or small light steels (lp50s), but with those you'll need weight options.

 

[rjack321]

Lp 50s are awesome tanks to sidemount. But even topped off to 3600psi they won't give you the gas you are calculating. What I do if I wanna do two longer dives with them is use them on the first and then carry an 80 stage on the second.

Yeah I don't know how the 165cf + reserve value was calculated at all, nor why he's diving thirds in recreationally open water. Perhaps before attempting to find a tank to fit the OP's "needs," it might be a good idea to understand how those requirements were developed.

 

[ffdiver]

Diving thirds isn't the issue and it's fine to keep that much reserve while diving open water.

I just re-read his post the 165 cf is for two dives total. Which is possible with two HP 100s, 2 LP 85s pumped up a bit. 2 LP 50s pumped up and a stage bottle.

The 45s won't get you there unless you carry a stage or really pump them up. IMHO the 50s are better for 2 short dives rather than carrying LP 85s or HP100s which are essentially the same tanks. The HP 80s are short tanks and for someone tall may not work out trimming right.

If you are willing to carry a stage the 50s plus 80 gives you plenty of gas for 2 dives and doesn't hurt the back carrying all those tanks.

 

[victorzamora]

If you already have an HP100, and you don't mind carrying an LP85 on land (slightly bigger than the HP100, actually)......I'd simply buy a second HP100. It's what the SMS75 was designed around (well, that and the LP85....which is practically the same tank).

 

[rjack321]

Diving thirds isn't the issue and it's fine to keep that much reserve while diving open water. .

Well when you are diving thirds recreationally "+ an extra reserve" then complaining the hp100s are overkill, yet al80s require too much lead, perhaps reexamining how you arrived at carrying 1/3rds plus more for recreational dives is in order. The concept of rock bottom still applies (at the end of dive 2). Carrying more gas than that recreationally is unwarranted and this might resolve the OPs issues.

Lamont and Gratefuldiver both have well written posts and pages on rockbottom calcs. Looking those up is a lot less hassle than buying and hating more tanks.

 

[a878bob]

SMS100 weight pouch fits nicely on a SMS75.

 

[GDI]

I have lots of dives in Canada even your neck of the woods. I don't know why the LDS will not fill LP72's but that is their call on safety. If you could get LP72 filled then they would be great. Failing that HP85 or 100 are a good size. You can purchase (even in Canada) HP 72's Bluesteel made by Faber. I have a couple of these because of side-mounting and they are excellent. If you can get them try to get opposing valves, right and left hand it makes for better routing

 

[Jim Lapenta]

That's not a safety call.
Edited comment, just saw the post on them not being TC approved. Apologies to the shop. It's TC Canada that is dumb