Stringer drain hole clogged

[MM33]

Hi Guys, The rubber tube running through my starboard stringer is clogged. I noticed this because water fills up and eventually only drains over the stringer. I tried using a snake and broke it. i got a tube that was slightly smaller that the rubber hose, ran it into the drain hose then tried a 6 hp shop vac to vaccum it out with no success. I also tried blowing it out using the same shop vac with no success. I am out of idea's so I figured I would see if anyone has any other ideas. thanks.