If the boat has an aluminum mast .... leave the rigging ALONE.
The aluminum has a higher 'coefficient of linear thermal expansion' than the stainless steel wire of the rigging .... and in COLDER temperatures will shrink MORE (about 1.4 times more) than the stainless wire, thus automatically 'unloading' the tension is the 'whole system'.
ALUMINUM: 12.3 X (10^-6 in/in oF)
300 SERIES STAINLESS 9.0 X (10^-6 in/in oF)
Aluminum expands or contracts about 1.4 times more than 300 series Stainless due to 'thermal' changes.