Is it me or is that place tough?  Fished 2 weeks ago in a kayak from the ramp at the Naval place to halfway before smallwood.  Caught 2 dinkers in 6 hours.  Nothing was biting till I got the dinkers on at low tide by the grass.  tons of bass boats out there though fishing the side but I didn't see any large pullage either.

Depending on the time of year, weather, and tides Mattawoman can either be world class or frustrating as hell.  Once the summer arrives I find that Mattawoman is a little bit more consistent, frogs over grass beds and texas rigs or cranks along grass edges consistently put fish in the boat and punching mats can give you some real bigguns.  During the spring the fish move around a lot and are more vulnerable to inclement weather.

It's all tough, but nothing beats time on the water.  Mark is right about the seasonal predictions, the fish are defiantly more stable in the summer.  Just keep at it and you will figure it out. 

Mattawomen is a fun place to fish and I don't know if this will help you out but try it if you want it work's pretty good for me any time of the year there.

I work parallel to the banks roughly 15 to 20 yards out and I use craw dads with a clicker and a lot of patience especially with that many bass boats around.

But be sure you take into concidaration what RockvilleMDangler stated about the weather and you should have a good day.