Combine first 3 ingredients in top of a double boiler. Gradually add orange juice, water, lime juice, and egg yolks; stir until smooth. Cook over boiling water, stirring constantly, until thickened and smooth. Remove from heat; stir in orange rind and butter. Pour filling into graham cracker piecrust.
Beat egg whites (at room temperature) and cream of tartar until foamy. Gradually add remaining sugar, 1 tablespoon at a time, beating until stiff peaks form. Spread meringue over hot filling, sealing to edge of pastry. Bake at 350° for 10 minutes or until meringue is golden brown. Cool to room temperature before serving.