Different people seem to have differing tolerance to cold water immersion.
I lived in the southeast for a while and frequently paddled on water in the upper 40s to 50 degree range and got pretty used to it. When I moved to northeastern Pennsylvania and paddled creeks in the early spring in snow melt the water temperatures were below 40 degrees. For me the difference was dramatic. I found that even with good protective clothing a swim in water of that temperature was almost immediately debilitating.
I would be cautious about a trip that would require a prolonged hike out after a swim until you know how you will react. If you do go, I would take a towel and dry fleece in a dry bag as well as fire making materials so that you could get warm and dry after a swim, and then I would resolve to hike out.
EZ-Dock modular docks
Deck Rigging Gear
PFD's (Life Jackets)
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