Rus ships HP bug

There is another bug specific to Rus. When reach castle age, the attack ship has 600 HP with HP upgrade tech researched. If research the armor +2 tech as well. Newly build attack ships will have 900HP. However the ships build earlier remains 600 HP or 400 HP. Transferring between different types of ship is more funnier. 900 HP attack ship could transfer into a 675 HP explosive ship. 600 HP ship ==375 HP explosive ship. Blacksmith range attack tech can also be transferred to explosive ship.