First time DSMB

[ronscuba]

A larger / taller SMB can be an advantage *IF* it arrives at the surface completely inflated, and *IF* the diver can keep it upright. A 6'ft SMB that's 1/2 full and requires 1/2 of the that 1/2 be pulled under water to keep it upright is less effective than a full 1 meter smb that has 90% of it out of the water.

If one launches any SMB from significant depth there is a good chance it will be full at the surface, much less so from shallow depth. Being able to fill a large SMB when shallow and maintain depth requires considerable practice and skill.

A large SMB can also require the diver be significantly negative in order to generate the force required to keep it up right.

What's easier to see? An upright 1 meter bag or a 1/2 full limp 2 meter bag lying on the surface?


Tobin

How do you know what it takes to keep the SMB up right ?

 

[cool_hardware52]

How do you know what it takes to keep the SMB up right ?

It's simple physics. A taller SMB with proportionally more mass at the top will require a greater counterweight to keep up right.

Just look at a short round buoy vs a tall marker. The tall marker requires a huge counter weight.

In addition I have actually directly compared the ballast required to keep various length smb's vertical at the surface. Any wind increases the required ballast. As wind is a common companion of large swells, making a tall smb much more likely to lie down in exactly the conditions where a taller SMB seems like a good idea.

I spent a bit of time investigating how best to get a smb to:

1) Arrive at the surface full

2) Stay upright

Before I started to manufacture the DSS SMB.


Tobin

 

[dumpsterDiver]

Yes, the times when you need a really big marker are when it is rough. When it is rough, the wind is blowing and it will push the smb over and long ones will also just fold over in the middle. So.. I've never seen much utility in a really large smb...maybe a search plane would see a giant one more easily when it is laying in the water?

 

[cool_hardware52]

Yes, the times when you need a really big marker are when it is rough. When it is rough, the wind is blowing and it will push the smb over and long ones will also just fold over in the middle. So.. I've never seen much utility in a really large smb...maybe a search plane would see a giant one more easily when it is laying in the water?

There are much better solutions for aerial searches. Dye Markers at the top of the list.

or a Streamer like this

<iframe width="640" height="360" src="" frameborder="0" allowfullscreen></iframe>


Tobin

 

[Littlerayray]

I like that streamer it won't dissipate and is highly visible

 

[Tralfamadore]

This is the general advice I give to all my students......
Get a 4-5' smb, they are easier to fill, retrieve, practice with and inexpensive.
Get a 100' spool with a 4" double ender. Line color doesn't mater.

This is a low cost option, allows the basics to be practiced and is applicable for a very wide % of situations. Once you become proficient then you can analyse your dive, objectives and surroundings and choose your dsmb's.

Watch this video on how to properly deploy one.....

Can someone explain to me what he is doing at the end of the video once the dsmb has been employed? He's taking back some line attaching the bolt snap then taking back more line?

 

[noj3333]

The line that's heading to the surface, wrap that line around the hook of the bolt snap several times (the bolt snap must be held in the open position). Then close the bolt snap (with several winds of line around it) in one of the holes on your spool. This will lock the line at a specific length.