In my story, I have a small extended family of 30 to 40 individuals ranging in age from 0 to 50 who are on the run from Chinese and Japanese forces in 1400AD. No place in Asia is safe for them. By a series of lucky chances they have found a very quiet location that appears to be untouched by humans. Escaping by getting out to sea is of the utmost importance. Trade of any kind will give them away so they must do all their preparations in secret and by themselves.
They have access to plenty of wood and iron ore deposits. Their location is sufficiently remote that they have up to 5 years to complete their ship and get out to sea. The refugees are traders, not craftsmen or metalsmiths. Iron is known to them but they don't have anything other than introductory knowledge of how to smelt iron or form tools.
What will they need in terms of construction supplies and construction facilities in order to build a ship strong enough to get them across the pacific? How likely is this little band to pull of this kind of a project? Commentary about provision requirements to put in the ship or the required ship size is also welcome.
- Small herd of horses, 5 cows and 1 bull.
- They have the iron tools required to maintain their tents and herds but they don't have any blacksmith tools. (They were in a bit of hurry to get out and didn't bother to kidnap a blacksmith or shipwright.)
- Ceramics are their primary eating and cooking implements.
Note that this is a hard-science question. You must account for the laws of physics when figuring out the size of the ship, the nutritional and water requirements of the crew. If you must handwave, please provide some justification for your guess.
While the following information is unknown to this little band of fugatives, please incorporate it into your answer.
- It takes about 2.5 years to drift from the shores of Japan to California so their voyage won't take any longer than that.
- They don't know it but they are attempting to get from Japan to the West Coast of the United States along the northern portion of the Northern Pacific Gyre.