Leather pencil holder and pen case by Cream Co.

This sketch sack is essential. 

When you get on the car ferry headed to Seattle and find a booth with a table that isn't occupied yet, you'll sit down, get all of your sketch supplies out, and settle in.

It turns out that you were unprepared for that container ship cross-swell wave that hits the ferry knocking your pencils onto the floor, rolling out the back door into the drink of the Puget Sound.