My preparation for sailing from the NorthWest United States (Puget Sound) to Mexico and beyond included several forays into the Pacific Ocean and one trip UP the West Coast of Vancouver Island into the cold prevailing NW winds and swell. It was an excellent shakedown and learning
I had done many Swiftsure sailboat races as a crewman, which in the 1970's went out to the lighthouse boat in the Pacific ocean. That was good education about the technical aspects of high performance sailing in the cold and damp North Pacific
Ocean. But the trip on my own boat, as skipper
and decision maker, 100-miles offshore
at 50 degrees N was whole another experience.
The trip from Japan to Vancouver Island/Pacific NW will take you to at least 49 degrees North and into some very cold air and water. If you have not sailed for days at a time in 50 F degree water and 52 F degree air you have no idea how debilitating the cold can be. My friends said they went two weeks without seeing a day of sunshine or temperatures above 53 F degrees. Many of the days were foggy or had light mist - those two weather
features just suck the heat out of you, no matter what you wear.
Therefore, you need some extensive sailing/living aboard experience in YOUR boat at 49 South.
A 3,045 NM NONSTOP trip from Sydney to the south end of Tasmania then SSE to Auckland
Island at 50.5 South and back to Sydney would give you a good feel about the 4,100 NM challenge of Japan to Vancouver Island NONSTOP. At the end of the Auckland shakedown you will be back at home if you find cold water/high latitude sailing is not to your liking.
If you wait to test yourself NE of Japan it will be a long slog home.
Our boat has a superb diesel
heater that forces air into every compartment. I've spent over 70-days sailing offshore
in the cold Pacific waters north of San Francisco
and was only warm on a few of them. I've taken four boats from Seattle to Mexico and in everyone we ran the heaters pretty much non-stop until south of San Francisco
I spent my 50th birthday sailing south under a spinnaker
30-miles west of Vancouver Island at 48 N in bright 54 degree sunshine on July 27 - just about the warmest day of the year in that part of the world. We spent 30-days sailing between 45 and 51 N in July (the northern hemisphere summer) and saw fog
on 15 of them, more than 4-hours sunshine on 5 and light mist on 10 days.
That will be you weather from the SW tip of the Aleutian Islands to Vancouver Island and on south to San Franciso - about 2,900 miles or 20 days in a fast 35-foot boat.
But - a cabin
heater is about the last thing you need in Mexico and we did not use ours once in the three years down there.
You will have to equip your boat for special Japan to San Francisco conditions that you probably won't see anywhere else. Is it worth it?