4. No Neutral Density Filter, No Problem
If you did not pack neutral density filters for your trip, there is no need to kick yourself if an opportunity for a long exposure presents itself. It does take a little familiarity and processing in Photoshop, though. Compose your image and take between 15-20 shots with that composition.
You need to shoot in burst mode or ensure that the intervals between your shots are as small as possible. Download your images and load them into Photoshop as layers.
Select Auto-Align Layers from the Edit Menu and Auto. Click OK when done. Next, convert your layers into Smart Objects. You do this by selecting the Layer menu, Smart Object and Convert to Smart Object. This step may take a few minutes to process.
When that is finished, go back to your Layer menu and Smart Objects. In Stack Mode, choose Mean (or Median also works well). This process also takes a few minutes to run.
The result, silky smooth water as if it had been shot with a neutral density filter and really long exposure.