SMBs - DIY?

[rollerboi]

Has anyone considered making their own delayed surface marker buoys?

If so, how have you done it? Simple open-bottom design, for expansion of air beyond capacity, or would you consider a valve necessary?

 

[Guba]

Take a look at my gallery...I have pix of simple markers. They work great as long as they are not over inflated at depth...no relief valve.

 

[mddolson]

I have an relatively inexpensive SMB ($15) These are available on eBay.
I is a simple bi-laminate nylon & polyurethane construction. It also has no relief valve.
If you over inflate it at depth it/they can burst/rupture on the way or at the surface.

I am presently looking a fitting it with an old dry suit or BCD relief valve to solve the problem.

The open bottom type can, like lift bags deflate/colapse suddenly in heavy waves.

Mike D

 

[Charlie99]

I have an relatively inexpensive SMB ($15) These are available on eBay.
I is a simple bi-laminate nylon & polyurethane construction. It also has no relief valve.
If you over inflate it at depth it/they can burst/rupture on the way or at the surface.

Somewhat surprisingly, a very commonly available "surface" signalling sausage without a relief valve works very well as a DSMB. Sold under several names including See Me, this tube will bleed out excess air through the fabric (nylon ?? cordura ??).

I use a 4" x 44" tube with about 30' of 2mm cord wrapped it as a DSMB. Typically I deploy it from 20-25' depth with one full breath of air in it. It will expand fully on the way up. It stays fully pressurized (maybe 1 or 2 psi or so -- more than I could possibly inflate it by mouth) on the surface.

I learned the trick from a Cozumel DM. When I asked him if he had to be careful to fill it just the right amount, he chuckled and on the next dive we launched one fully inflated from 100' ---- it just fizzed all the way up and had no damage.