Your marina mechanics are right.
Presuming you mean the “Liberty Landing” in
Jersey City, NJ, it won’t be safe to leave
water in the
engine from late November through March, when you can expect freezing temperatures (20's & 30's F).
These temperatures may not freeze the marina, but can certainly freeze
water in the hoses and galleries.
* January has an average minimum temperature of 22.70 degrees Fahrenheit.