How cold is still ok for the boat to be in the water all the time?

Around here (Switzerland) the lake (130 m deep) has last frozen 40 years
ago, and with global warming it is unlikely to happen again.
We get at most maybe -10 degrees C (14 deg F) in cold nights, most of
the time less, the water most likely does not freeze at all.

What are the critical parts in a cabin cruiser (petrol/gasoline) that
limit having it in the water all year round? And at what temperature do
you have to take it out? Or is it possible to keep it in the water?

(SeaRay 315 Sundancer if that matters - cabin, water, head and all that).

Thank you in advance

Marc

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