is there any way i can make a use of ships once they fall behind tech level? ive still got carracks in 1650s and i feel like theyre just going to be worthless soon
If your hitting your support limits and have the cash then replace them. They cost the same as a modern ship and will not be as handy in a fight. Barques are fine as they just sit in port to deter pirates but big ships are meant to fight so you should probably scrap them.
If you don't have the cash/ports to replace them quickly just use them to blockade.