I'm almost ready to varnish my Osprey Double. After sanding, should I wash the entire boat (soap and water)?

I've read that some thin the varnish. I am going to use Captain's varnish. Does this need to be thinned, if so with what?

What is the best method for application, foam roller or foam brush, or is there another method that works better?

What is the process between varnish coats? Steel wool, those 3M pads?

I will finish this thing sooner or later. I have to admit that I am getting a little sick of sanding at this point. My wife tells me not to be impatient and that I will be sorry if I rush and don't do the job I want to do. She's probably right.

Thanks,

Tom