how to fill SMB ballast with water???

[ballastbelly]

i got a simple ball smb, it has 1 valve on top for air & other on bottom for water

but i can not figure out how to fill the bottom when at the seaside. no amount of holding the smb under water, inflated or not will get any water inside the water bladder in its deflated state. am i supposed to use a syringe or something? thanks



PS if referring to a pic of it makes it clearer, see:

 

[Redzepp1011]

you may want to try blowing some air into the water reservoir (while the air side is deflated), then hold it under the water and open the water reservoir valve. The air you blew in should be displaced by water...