A gallon of water in the engine oil

[spydermann22]

Last time I used my boat -year 2000 2300SC 5.7 Liter - it ran flawlessly, this was several weeks ago. I went to winterize it last weekend and it wouldn't even turn over - I actually got it to turn about a quarter turn. The batteries checked out ok so as I checked things, I found the oil was way overfull.
I had changed the oil this season and checked when I was done and have checked often. I decided to pump out the oil and what came out first was a full gallon of water. There was no water in the old oil when I had changed it previously so I am thinking something like a head or intake gasket went suddenly.
I am in Minnesota and it is getting cold fast so I need to figure out my next step very quickly. I do not have a indoor place to work on the engine so I am considering waiting until spring.

What I THINK I need to do next is:
1) pull the spark plugs and try to turn over (pumping any water from the cylinders),
2) fill the oil up (it is empty right now)
3) pull off the coil wire and turn the engine over to circulate the oil (I don't want to have the water hooked up to avoid any more water from entering, and also do not want the motor to start with any water potentially anywhere inside or burn up the impeller)

I dont think I want the engine to start without any water hooked up as it would burn up the impeller. Maybe I should pull out the impeller and run the engine for a couple of minutes.

Any suggestions would be appreciated.