Bring water to a boil; add shrimp, and cook 3 to 5 minutes or until shrimp turn pink. Drain well; rinse with cold water. Chill, peel, devein, and coarsely chop shrimp. Position knife blade in food processor bowl; add shrimp, butter, and remaining ingredients. Process until smooth, scraping down sides occasionally. Line a 2-cup mold or bowl with heavy-duty plastic wrap, allowing plastic wrap to extend over edges at least 5 cm. Spoon shrimp mixture into mold; cover and chill at least 4 hours. Invert mold onto serving plate. Remove mold, and carefully peel away plastic wrap. Smooth surface with a knife, if necessary. Let stad at room temperature 20 to 30 minutes before serving. Serve with assorted crackers.