The personal property of automobile transportation companies owning, controlling, operating or managing any motor propelled vehicle used in the business of transporting persons and/or property for compensation over any public highway in this state between fixed termini or over a regular route, shall be listed and assessed in the various counties where such vehicles are operated, in proportion to the mileage of their operations in such counties: PROVIDED, That vehicles subject to chapter
82.44 RCW and trailer units exempt under *RCW
82.44.020(4) shall not be listed or assessed for ad valorem taxation so long as chapter
82.44 RCW remains in effect. All vessels of every class which are by law required to be registered, licensed or enrolled, must be assessed and the taxes thereon paid only in the county of their actual situs: PROVIDED, That such interest shall be taxed but once. All boats and small craft not required to be registered must be assessed in the county of their actual situs.