SMB open bottom or closed?

[DarinMartell]

I'm thinking about upgrading my smb. Right now I have a 4ft with an open bottom (magnets keep it together). I don't like this because I could not lift it out of the water to get a boats attention. However, can you "shoot" a smb that has an oral inflate?

Or should I just keep my 4 footer and spend my $$ on a different toy?

[b1draper]

Originally Posted by DarinMartell

I'm thinking about upgrading my smb. Right now I have a 4ft with an open bottom (magnets keep it together). I don't like this because I could not lift it out of the water to get a boats attention. However, can you "shoot" a smb that has an oral inflate?

Or should I just keep my 4 footer and spend my $$ on a different toy?

[FONT='Verdana','sans-serif']Both open bottom and closed bottom SMBs have their advantages and disadvantages. I personally have a closed bottom SMB with an oral inflator. Depending on how deep you are it can be difficult to judge how much air you need to inflate the SMB. I would suggest getting a SMB that also has an over inflation valve.

Both open and closed can be shot from depth. With the one that has the oral inflator it usually takes only a breath or two to inflate it. I would suggest having a SMB a little bigger than the four foot one that you have now. I'd suggest a 6' one with one side orange and the other yellow/green with the over expansion valve.[/font]

[CompuDude]

It all depends on local needs whether you need a bigger one or not. We don't use them much in SoCal, so the little ones are just fine for most needs.

Wreck divers in the Atlantic and people dodging drunken motorboaters in Florida may need a bigger one, however. You get the idea.

There are a number of types of SMB, but if you want to lift it above the water and wave it around, yes, you'll need a sealed one. Halcyon, Carter, and others make some nice sealed ones. You use your drysuit or BC inflator hose to fill them. Some of them also have an oral inflation valve, but for a big bag you'll need to be pretty deep when you shoot it to orally inflate and give it enough room to expand to fill.

[navyhmc]

I would agree with geting a 6' SMB. Higher out of the water, the better the visib from the boat. NavyOnStar had a good thread on this last month: Coast Guard Search Criteria - increase your chances of being found! and Best Emergency Attention Getting Equipment

Another thought is if you have a open bottom SMB and want to wave it around, fold the bottom over a few times and hold it there. You mavy lose 3"-4" of length, but it will keep it air tight.

Personally, I went with a 6' SMB. But, you can shoot a oral inflated SMB from depth, but remember that volume expansion. If you shoot it from aroung 33' you should only inflate 1/2 or a little less. 60' go with 1/3. I am not sure if the SMB's with just an oral inflator have a relief valve or not. Would definitely suck to shoot a SMB, have it going up well then it stops, your line goes slack followed by this limp ruptured SMB floating down past you.

[DarinMartell]

"It all depends on local needs whether you need a bigger one or not. We don't use them much in SoCal, so the little ones are just fine for most needs.

The waves get pretty high on Lake MI. So a 6 footer might be good.



"you can shoot a oral inflated SMB from depth, but remember that volume expansion. If you shoot it from aroung 33' you should only inflate 1/2 or a little less. 60' go with 1/3. I am not sure if the SMB's with just an oral inflator have a relief valve or not. Would definitely suck to shoot a SMB, have it going up well then it stops, your line goes slack followed by this limp ruptured SMB floating down past you."

Would leaving the oral inflate valve open act as a dump valve?

[Duckydiver]

I have the DAN SMB which has an open end that does stay closed when the smb is out of the water. Its a 6 foot tubem you can inflait it either oraly or with a second stage, it also has a presure relef valve. Alot of other bells and whisles to list. I highly recomend it.

[navyhmc]

Originally Posted by DarinMartell

Would leaving the oral inflate valve open act as a dump valve?

Probably not. You need something to keep the air and the pressure it develops once it's at the surface. If you are intending to shoot a bag or in this case a SMB for a reference line or for a safety stop line, you wil need a near full and non-venting SMB to maintain your line tension. If you leave the vavle open evne a little, it will lend itself to deflation.

[CompuDude]

Have you seriously ever orally inflated a 6' SMB? Even with the volume doubling if you shoot it from 33', or tripling if you shoot it from 66', it takes several breaths to fill that much, and you're looking at a serious amount of pull before you can release it, even only filled 1/2 way or 1/3 of the way. NOT an easy skill. Only by using an LP hose or Octo do you generally have much chance to get it full at the surface, when you shoot one from depth.

[Osseous]

Mine has a funnel shape to the open end- and once you fill it (just a little bit of air does the trick- doesn't have to be totally full for this to work) the funnel self-seals and it holds air fine. It has an oral inflator/LP inflator attachment too- but once I discovered this self-sealing feature, I figured that I only ever needed to use my Reg 2nd stage. Also has a velcro loop to turn it into a horse collar at the surface. Neato~

[DarinMartell]

Originally Posted by Osseous

Mine has a funnel shape to the open end- and once you fill it (just a little bit of air does the trick- doesn't have to be totally full for this to work) the funnel self-seals and it holds air fine. It has an oral inflator/LP inflator attachment too- but once I discovered this self-sealing feature, I figured that I only ever needed to use my Reg 2nd stage. Also has a velcro loop to turn it into a horse collar at the surface. Neato~

what brand?