I have gone through the ice and gone in the water ..Totally..up to my neck, while Iceboating (Sail). I was wearing a "Snowmobile Suit" and Helmet. My initial response was ..OH..THIS is not good.

The secondary response was involuntary..
Shrinkage.
It is NOT that Bad. The mast was now laying over horizontal to the ice. I paddled and walked over the sail..like a trampoline..walked up the sail on to good ice and got out of the water. It was NOT that cold. My sailing companions were there pretty quick. .........What to do now...?
Retrieve the boat: The boat has to be Un-Rigged to get it out of the water. NO Problem: I went
back into the water to pull the pins for the rigging so the mast could be removed and the boat hauled out onto the ice. It took only minutes.
Once the boat was retrieved, it was RE rigged on the ice... a companion loaned me a Dry snowmobile suit and I resumed sailing. I think I was around 28 or 29 years old..??

NB
YUP: I have been there and done that....