What would it take to build a ship capable of crossing the Pacific?

Question

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.

Equipment List

• 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.

Helpful Information

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.

Answer 1

They fail and suffer whatever evil fate awaits them.

...or this

I say this mainly due to this pre-condition:

The refugees are traders, not craftsmen or metal smiths. Iron is known to them but they don't have anything other than introductory knowledge of how to smelt iron or form tools.

Having all the natural resources is great, but they have no knowledge of ship-building, metalworking, sailing (at least not across the ocean), astronomy/navigation or geography...that kind of knowledge is what would allow them to succeed and that takes years of practice/study to get.

To build a ship of sufficient size you would need specialized tools to support the entire supply chain from resource collection to putting the ship together. You need cranes, special saws...the list goes on and on....and on.

It's possible they could get a ship built, but odds are it would sink straight-away...after all the first version of anything is usually a complete and utter failure.

If they don't know they can stop they would also need food and clean water for, as you mentioned, up to two years...that's a lot of weight and storage space.

As it stands your scenario stretches plausibility to the breaking point for me. The learning curve is simply too much to overcome.

• There is not enough time to learn metal working/shipbuilding/navigation (among others) particularly if they are teaching themselves. Trial and error takes a lot of time.

• Time, there will be other considerations on these peoples' time. Raising children, for example, not to mention farming/fishing, building shelters etc.

• Raw materials. There are materials other than wood and metal to get which require other skill sets. You need something to seal the wood, you will also need fabric for sails, not to mention clothes.

• Food and water. Storing food and water for a long sea voyage is not easy, you need water tight containers and preserved food.

The list of things to learn (for reference):

• Metalworking
  • Mining
  • Smelting
  • Black-smithing (includes creating tools for this and all the other specialties)
• Woodworking
  • Forestry (what kind of wood to collect)
  • Milling (creating usable lumber)
  • Ship building
  • General carpentry (building tools, homes, barrels)
• Navigation/Travel
  • Astronomy
  • Geography
  • Sailing (managing a vessel at sea, sails, storms, no wind etc)
• Other
  • Farming, including preserving food for a long trip
  • Collecting material for fabric
  • Creating thread
  • Weaving
  • Fishing
  • Sealant (Sealing of the joints on a European sailing ship was done with caulk, which was a combination of oakum (plant fibers) and pitch (tar). Thanks @KillingTime

Oh...not to mention you need geometry and some fairly advanced math to design a ship, build cranes and such.

Answer 2

This has already been tried and proven, and is referred to as the Kon-Tiki expedition:

Heyerdahl believed that people from South America could have settled Polynesia in pre-Columbian times. ... His aim in mounting the Kon-Tiki expedition was to show, by using only the materials and technologies available to those people at the time, that there were no technical reasons to prevent them from having done so. Although the expedition carried some modern equipment, such as a radio, watches, charts, sextant, and metal knives, Heyerdahl argued they were incidental to the purpose of proving that the raft itself could make the journey.

...

Heyerdahl and a small team went to Peru, where, with the help of dockyard facilities provided by the Peruvian authorities, they constructed the raft out of balsa logs and other native materials in an indigenous style as recorded in illustrations by Spanish conquistadores. The trip began on April 28, 1947. Heyerdahl and five companions sailed the raft for 101 days over 6900 km (4,300 miles) across the Pacific Ocean before smashing into a reef at Raroia in the Tuamotu Islands on August 7, 1947. The crew made successful landfall and all returned safely.

Even better, there were several later recreations of this voyage by others. Crossing the Pacific using simply-built boats and carrying enough supplies for the passengers is daunting, but certainly possible.

Answer 3

I'm sorry, but you need to change your story. I think you can, and I hope you do: from a dramatic standpoint, it's a hell of a good tale in the making.

However, you have set your protagonists up to attempt something that's just not reasonably plausible. You burden them with inventing, from scratch, too many things that just can't be invented that way.

I have been a sailor on submarines, yachts, an oceangoing tug. Until you've actually been to sea, it's hard to get your mind around just how damned much there is to know. I really like the answers from @James and @bowlturner, and won't bother to add more critical or significant prerequisites. But please do review those lists.

Your challenge, as I see it, is to retain the dramatic narrative, but back off on the intractability of the problem. And really: the Sea provides enormous amounts of drama, without layering impossible and unrealistic challenges on the protagonists. You can relax the stringent constraints that you have declared, and it will still work.

You have the bones of a pretty thrilling story there.

Answer 4

To get a grasp of how likely they are to fail, let's study the voyage of Magellan across the Pacific.

• Magellan started 100 years after this, from a society with more advanced shipbuilding.
• Magellan's ships were built by trained shipbuilders in a culture with a long history of building seaworthy ships, having access to the tools and resources a whole kingdom could provide.
• Magellan had experienced men, with all the skills necessary for the voyage.
• Magellan had 270 men, all capable seamen, without bringing children with them. They were also (mostly) knowing what awaits them, this also provides a good filter for what kind of men he had, in the opposite of a few unlucky traders who are not prepared to such a journey.

Despite all the numerous advantages Magellan had over your characters, his expedition just barely made it. The expedition lost 80% of the ships and over 90% of its men on the way!

Yes, the expedition circumnavigated the whole planet, but they had colonies in South America where they could resupply, and after reaching the Indian ocean there were also European colonies and outposts, so the only unknown part of the journey was the Pacific.

Answer 5

There is a huge amount of knowledge that is needed that these people are missing and so most likely all will die.

Any one of a large set of skills needed to make this adventure work are missing.

At that time, especially in Asia, 'cross-training' didn't exist, and guilds kept their secrets close (not to mention that often one group felt things 'weren't their job' kind of things. So there is a huge social impediment right off the bat.

Blacksmithing

Now Blacksmithing, your average blacksmith apprenticed for maybe 10 years before getting a 'journeyman' status and up to another 10 to become a full fledged blacksmith. So maybe 10-20 years to become a good blacksmith and this is with a competent teacher. Smelting alone is rather knowledge intensive and I don't think I would have much luck, without a lot of trial and error. (this is of course being able to recognize the ore, being merchants they might).

Mining

So you get your ore, smelt it to something sort of useful. and then use rocks or casts to try and make first level tools. These might be good enough to make better tools (such as a decent hammer).

Nails, collars hinges, axes, adzes, shovels, knives and other tools will all need to be made before you can start working the wood needed to build a boat. Granted many nails can be replaced by wooden pegs (and many should) you still need to make the pegs AND the holes to put them in. The poorer the iron quality and the poorer the blacksmith the more of these will need to be made as they keep breaking.

Logging/forestry

Next, logging, needed to be able to select trees, cut them down, shape and haul them to the build sight. Lots of logistics (once again a possible skill merchants could possess), and a bit of engineering.

Carpentry

Now you have your trees as logs. You need to turn them into lumber to be usable, even just strapping the logs together as a raft will need a bit of shaping, trees really don't grow nice and straight.

Ship building

Ship wrights, there is a reason there is a name for this type of wood work. Knowing how to put a ship together for more than a small fishing boat requires a lot of knowledge for the stresses put on the ship and which woods are best for which parts, ribs, sides, masts, decking etc.

Textiles

Now you need rope, this is something that might be a reasonable skill to get to pick up or figure out, though good rope still requires some knowledge, since the cows are limited it is unlikely to be leather ropes (and somethings shouldn't be leather on a ship). You will also need sails, so while they might understand good quality, it's a far cry from being able to make canvas or what ever fabric might be available.

Food stores

Food preservation, even a several month journey across the oceans will need to have the food preserved well since water will destroy stores. and you will need fresh water as well. Both of these need a cooper to make barrels (both blacksmithing skill AND woodworking knowledge.

Navigation/Seamanship

Now even if they just stole a ship that was already outfitted and sea worthy, they have navigation to contend with, starting with they don't know where they are going nor how far it is, essentially they are willing to 'die' to try to find a new place to 'live'. If they are in the north seas during winter they will likely die from the storm smashing their ship. It still takes modern ships to the bottom today. These are manned by experienced sailors too. Which brings up seamanship and the ability to control a ship at sea, controlling the sails and KNOWING when to use more sail and when to reef them, and how to ride out a storm.

Answer 6

As has been said several times already, if you stick to the idea you've laid out here, your protagonists are doomed to a horrible death at sea. The best way for at least some'of them to survive their journey without breaking your rules too much would be to adopt the methods used by the Polynesians. Obviously, the Polynesians had probably been traveling by sea for thousands of years before they crossed the Pacific, but your characters clearly don't have time for that, so the best their best approximation of Polynesian practices is as follows:

1. Ditch the livestock and eat something more convenient and appropriate. Your primary source of food should be fish, because the increased weight is minimal. You'll need plenty of line anyway, so you'd already have that, and the only other necessity is a few hooks. You can't rely on your luck at fishing, so you'll need some back up rations. The Polynesians carried rats on long sea voyages. This sounds incredibly unappetizing to us, but it keeps you from starving to death.

2. Less is more. Your characters don't know how to build the kind of ocean vessels we would probably prefer to use, so they shouldn't try. The Polynesians used small canoes, usually with outriggers for stability and extra storage room. This approach comes with an obvious downside - the group won't be traveling together. Even if they try to stay together, it will be impossible to do so, especially if/when the first spell of bad weather hits.

3. Don't try to make the trip in one go. The Polynesians would read the signs provided by wave patterns, wind direction, and the flight paths of seabirds to find their way to the nearest island, and if it proved to be habitable, or even to contain useful resources, they would go ashore. Sometimes they stayed, sometimes they didn't, but they would exploit any opportunity to rest, resupply, and perform any necessary repairs before setting out to sea again.

4. Throw away everything you don't need before starting the journey. If you have farm tools, that's nice, but you can't afford to waste space aboard your ships. You're going to need to stuff every last nook and cranny with food, water, and other more essential items. Your only priority should be to stay alive on the trip, so you have to ignore all thoughts of what will happen if and when you reach your destination.

5. Because most of these suggestions involve relatively little preparation, your characters can spend as long as possible getting familiar with the ocean, and perhaps even sending reconnaissance missions out to find nearby islands. This should be their primary focus, and the main way they spend their days. The more they learn about the sea, the more likely it will be that they survive the expedition. They need to understand how tides work, what the sky is telling them about what the weather has in store for them, how to row and steer their vessels as efficiently as possible, and so on. If anyone is prone to seasickness, they absolutely must get over it before the trip begins. Everyone needs to build up the muscle strength needed to row for hours on end.

These tactics definitely don't guarantee success. Chances are, most or all of your characters are going to die very quickly, regardless of what they do. But this represents the course of action which provides the greatest chance that at least some of them will make it somewhere that they can settle down and start a new life.

Answer 7

Not to overly change your story, but a good alternative might be for them to forge their way along the N. Asian coast and across the Aleutians thence down the coast of Alaska. This way they could stop at villages along the way to get sailing knowledge and maybe some seeds for crops (BTW some crop seeds would be a good idea, maybe millet, barley, radishes?). They would be sticking closer to the coast in case of storms and also would get a lot of dramatic contact with other people along the way. Trust me, that route would still give them plenty of exciting high seas drama.

On the other hand, it is known that at least parts of ships turned up in the NW U.S. (and Alaska) area from Japanese and Chinese ships in pre contact days, so a direct crossing might "luck out" and not be lost. If it takes 2.5 years, though, they are pretty much doomed.

Answer 8

As others have said, they die.

Lets take a far easier scenario: The group has modern technology, all requisite skills and all relevant small scale tools. They still die.

Consider the supplies they need: For drinking water alone we are looking at nearly 8000 pounds per person. For medical reasons I have for a period of months lived on some stuff that's basically pure nutrition with no waste. For a pretty much sedentary life in climate controlled conditions that's still about another 1000 pounds per person. They are going to be in a cold climate with no source of heat, they'll be eating considerably more.

Furthermore, they won't have access to anything so concentrated. For a short period they could get away with eating things like butter (something that's sometimes done in extreme-environment travel because it packs so many calories per pound) but trying that for 2.5 years is suicide. Thus I would be shocked if the absolute minimum supplies could be gotten down below 10,000 pounds per person--and that doesn't count the weight of the containers that hold it. Storing it all in barrels seems to add 20% to the weight so we are up to 12,000 pounds per person--6 tons. (And given the limits of the available foodstuffs and the need to get the needed vitamins I think the the real number is considerably higher than this.)

6 tons * 40 people = 240 tons. Someone else mentioned the Santa Maria--nope, you'll need Columbus' whole fleet to do the job. That's just to get them to North America, they land with nothing but their clothes and they die.

That's assuming they even get the ships built. I'm giving them a much better start than you are but they still need to build the drydocks to build the ships before they can even start construction and most of their time will have to be devoted to simple survival. Back then most people spent most all their hours on survival, you are asking them to produce at 1.5x the normal rate (2.5 years of extra supplies obtained over 5 years) while devoting a huge effort into building a drydock and then ships.

A replica of the Santa Maria was built with modern tech--\$1.2 million. Lets take 10% off for taxes, all other costs are fundamentally labor at some point (if it's a material you're actually paying for someone else's labor). Lets assume a worker makes $50k/yr. That means we are looking at 22 man/years to build one ship--66 for the fleet. (Remember, this is with full modern tech!) Lets assume that 1/4 of the group is too young to contribute meaningful labor, that means we have 30 workers and I'll be very generous and assume they're working 80 hr weeks (I don't believe this is actually possible without decent artificial light) giving a total of 300 man-years of available labor. That's over 20% just for shipbuilding, not counting the dry dock.

Still another problem: You didn't have them escaping with any large stock of food. Unless there's plenty of wild foodstuffs where they go to ground (and if it's that lush why isn't anyone living there already??) they are going to be in serious trouble while they get their first crop in. Trying to live by meat alone means nutritional deficiencies.

Answer 9

A lot of answers here have targeted the information deficit in particular; that is probably the single biggest problem over these 5 years: even with the decision "let's build a boat" there are the problems of (a) we need to acquire water and food sufficient to maintain this endeavor, (b) we need to stay healthy through whatever injuries are going to happen; (c) we need to build enough blacksmithing knowledge to potentially build axes and saws, so that we can make planks; (d) we need to build enough sailing knowledge that we can build a seaworthy ship; (e) we need to have the surplus supplies stored so that we can actually make the journey, (f) we need to have enough information about sailing to make consistent progress away from our starting point. (That's not too hard if you're just sailing East, but you might mess up and lose track of direction during mid-day.)

Now as to size, this ship is based on older schematics, took about a year to construct with modern tooling, can house something like ~40-ish people, but mostly takes comparatively short trips up and down the Hudson River. In theory it should be seaworthy, based as it is on Dutch designs which were seaworthy, but I don't know that anybody's tested that. This ship is a schooner of about the same length; it says that it'll sustain 34 people overnight, but its cruises are listed as 5-day-or-so affairs. Either way they sound to be 100 feet long, which is roughly the ballpark for the size of ship you'll need.

In the 1400s, Michael of Rhodes wrote a manual of shipbuilding which includes a bunch of ships; his simpler "Galleys" are single-masted square-sail boats, which will be more common for the period and are principally powered by rowing. The sailboats ones that he lists measurements for are all about 66 feet long, and are wider for use carrying more cargo. One page comments

Neither measured plans nor even the technique for making them existed in the Middle Ages. Ship design, in the sense of determining final dimensions, was carried out in the yard at the same time as a ship was actually made. The main difficulty was not one of determining overall shape, but of determining the dimensions of hundreds if not thousands of individual parts that had to be cut from timber and assembled together.

So there's not going to be any recordings of ships available to them. Your best bet comes from the fact that these people are merchants, and therefore sailing was not out-of-the-ordinary for people in their profession. If five or ten of them knew how to sail and five or ten of them were in the cloth business and knew about spinning, weaving, and sewing, then it's possible that some of the knowledge gaps can be worked out over the course of their journey. But if you don't have blacksmiths or carpenters among them, you're not likely to get a 100-foot vessel in five years, even if you've got ten sailors who compare notes on the proportions of the vessels they sailed and five cloth-merchants who figure out how to turn plant fibers into sailcloth.

Answer 10

OK I'll take a stab at it : their chances are very slim for a direct ocean crossing but not quite zero, given a few preconditions.

1. They need someone with a clue. Now while they are traders, in that era that doesn't mean they know nothing else. You need to make and maintain your caravan's equipment for one thing. As they are handling money across many cultures, they will understand metallurgy : the purity of silver or gold in that coin matters enough that you can count on that. Even so :

2. Let us assume one of their band has a Viking ancestry and some serious maritime experience in his youth. Possibly via the Baltic and the great Russian rivers, across the Black Sea, so far all well-trodden paths to the Vikings. Then, "because of a killing" as the sagas might say in their understated manner, forced to leave town via a caravan onto the Silk Road and hence to China or Korea. (Choose another seagoing culture if you wish : Polynesian, or a Chinese sailor who no longer dares show his face in Shanghai; however I have a soft spot for the Vikings!). His experience guides them in the following:

3. Forget iron. If you can trade (or have traded) for some iron woodworking tools, good, but don't take iron to sea. Iron nails will simply disintegrate within months, while copper nails survive well enough they are still used in boatbuilding today. Copper - or bronze if you can make it from your store of coin - will survive the conditions far better, and the caravan probably already has the expertise to work it. You can trade for it without arousing suspicion, or you may have brought it in the caravan from Arabia.

4. He has some knowledge of ship construction on a basic pattern which is scalable from six-oared boat to Atlantic-proven merchant ship as well as sleek warships, and practical experience rebuilding small or medium ships when they rotted along his way. He'll be guessing when he builds a large ship, but he'll first build a smaller one, after all he has to train the rest of the group to sail. It would be likely for him to contemplate a small fleet including the first boat, rather than a single ship. I would far rather my chances in a Skuldelev ship - or a Polynesian catamaran if you prefer - than the high sided Santa Maria.

Basic construction is simple enough for one expert to carry: keel first, with stem and sternpost. Then strakes (planks) working out from the garboard strake, cutting and steaming into place, measuring with string from the centreline to achieve symmetry. The strakes hold their position without extra support. Then, in contrast with southern European shipbuilding, ribs last for strengthening. This gives a much lighter ship than ribs first, bending planks over them. Same technique is still used in the former Viking parts of Scotland though now sometimes in plywood!

5. Let's assume he has no knowledge beyond rumour of the Vinland or later voyages or any territory beyond Greenland. He will still know some basic navigation : determining latitude to keep the ship on an east-west course, and dead reckoning. (The Vinland Sagas, when discussing Greenland, do have some latitude - or rather, height of the sun - records) Still, while we know there's land out there several thousand miles away, he doesn't...

6. He doesn't know it but he's going to have to cross about 90 degrees of the planet's surface - at the equator that would be over 6000 miles : he's sufficiently far north to reduce that, but still he may have 5000 miles to cover. At 4 knots, in favourable winds (anything from dead north through west to dead south will do, for a square rigger) that would be over 50 days. However, what are the chances of that? You may want to research met conditions in those waters, but failing that : Double that, 100 days, would be a bare realistic minimum (as well as being where Columbus practically ran out of supplies), and double that again would be more likely. If they set off in Spring, that takes them until autumn, and I'm not putting any money on their chances through a winter. By late Autumn he knows they have found land, or not... (EDIT) This detailed chart for the North Pacific in June suggests their chances of a Force 4 Westerly (through SW to Southerly) are pretty good across most of the route, provided they stay between 35N and 50N. South of 35N they find more unfavourable winds... (you can find charts for other months there too)

7. Supplies and provisions for the voyage.. This is the difficult bit, but the "good" news -which he knows - is there's no point carrying much more than 200 days supply, rather than 2.5 years. The limiting factor is how much they can carry, how long it stays good, and whether they can replenish (fishing, collecting rainwater in the sails) on the way. Two comments : rice may help, though charcoal for cooking is precious. And don't be squeamish about pilot whales. Sorry, but the alternative is starvation...

8. And good luck!

Answer 11

This is doable.

I agree with Mr Drummond. They need someone with a clue.

I've seen five Indonesian shipwights start with a stack of lumber and build a fishing Prahu from the keel up in six weeks with no metal fittings. The only tools used were hand tools, adzes, saws and drills. All joints were pegged, planks were stitched together and joints sealed with coir (coconut husk) and pitch. For a voyage of this length you need a vessel about 30m (Think Bounty / Endeavour, Bligh & Cook) Magellan's problem was the same as Bligh's. They were sailing past Cape Horn E to W. Against the (savage) prevailing wind. Your guys are going with the prevailing currents and winds. Running before the wind places much less stress on the hull and rigging than beating to windward by at least an order of magnitude.

Bounty and Endeavour were Whitby Cats, designed to carry coal on the W Coast of England, picked in part because their broad flat bottom provided plenty of internal volume and allowed then to ground easily. You could go with a single vessel but I'd suggest a small fleet that way all eggs not in one basket.

For water allow minimum of 2l / person /day. You will get rain in those latitudes, particularly as you approach North America so all the water needed does not have to be carried initially. If they have ceramics they can also construct solar stills - early Eurasian culture has this tech. I'm sure some research will show the Chinese had it too.

The distance is about 3,800 nm but this is great circle & not recommended as it goes into high latitudes. The great circle actually passes through the Aleutians. An easier technique (and navigation) is to head due east. This is called Parallel sailing and was known to the earliest navigators. Navigation is easy. Keep the pole star the same distance above the horizon. If it get's higher, too far north, lower too far south. To work out the distance start to finish take the difference in longitude between the two places in minutes and multiply by cos Lat. Remember to allow for dateline.

Materials, if they are on the coast of Asia - bamboo. Light, tough, intrinsically buoyant. Can also be used to weave sails (as can coir and hemp). They will need a source of pitch / tar for waterproofing. The vessel(s) need not be durable. They only need last the voyage.

One skill they will need is that of Cooper. The're going to need barrels, lots of barrels. Not an unreasonable skill to find in a group of traders of that era. PS Cook started out as a shipwright. If they can find an experienced mariner he could be expected to be multi-skilled. Until the last 60 years all seafarers were expected to be multi-skilled lateral thinkers. If it breaks on voyage you have to fix it yourself with whatever materials are to hand.

Picking up Johns S' concerns. Having served on Bounty I'm quite aware of the nature of these vessels. I do not suggest that they try and build a similar vessel. (Without a 'Cook' and a blacksmith, with them it's doable). The point is that a vessel of this size & shape is within the design envelope sought by Green. Endeavour left Plymouth with 94 people and 18 months of provisions aboard. We sailed Mexico for a transpacific voyage (a much longer voyage than the one contemplated) with ~50 aboard Bounty and there was no shortage of room for both people or stores. The point is that these vessels are a good indicator of the volume and shape required. At 4 kt the ~4500 nm takes about 45 days. The big killer at these latitudes is exposure. Rafts would be a disaster. I vote for a decked vessel.

Answer 12

The voyage you're describing is comparable to Columbus's first voyage. Given that, there's a good model for the sort of ship you'll need: the Santa Maria. It holds 40 sailors and supplies for a ten-week voyage; like most ships of the era, it could be sailed reasonably well with half that many or fewer.

The problem is building such a ship. Carracks such as the Santa Maria represented the height of 15th-century European shipbuilding. A group of refugees isn't going to learn the skills needed to construct and sail such a ship, even if they didn't need to re-invent trades such as blacksmithing or carpentry.

Answer 13

The refugees are going the wrong way.

A high latitude ocean voyage on homemade balsa rafts or dugout canoes is suicide. You need real oceangoing vessels for that. There is a "right way" around the world and a "wrong way". Sailing west is relatively easy, and experienced sailors do this for recreation on modern ocean worthy sailboats all the time. Sailing east is definitely the wrong way, though, as you end up in the high latitudes to gain favorable currents and winds, but then you face frequent foul weather, which is a non-trivial problem if you don't have very capable boats.

Disregarding the kinds of sea conditions your refugees will face in a higher latitude ocean crossing counts as "handwaving" in my opinion. We are not talking here about the refugees just getting splashed with a little spray on occasion, but rather about their makeshift boats being totally swamped by walls of water, being rolled completely over, and being flipped end over end, or just being smashed into splinters. Assuming the boat survives this kind of abuse (big assumption with a balsa raft), everyone and everything not tied down is gone.

I am not kidding about that "tied down" part. Nobody will be able to just "hold on" while a medium-sized hill of cold water rolls across the boat, and that raises another point: Water in the high latitudes has a different, heavy quality from low latitude water. The water quite literally feels more dense when those waves hit you and your boat.

A high latitude ocean passage without properly constructed vessels and skilled sailors is suicide. Even if you are going to gunkhole up the coast to Kamchatka and island hop across the Aleutians, waiting for fair weather for each leg, there are still places where you will have to make deep water passages, and it is almost never nice sailing weather in that area anyway.

Answer 14

They could live

I wrote an answer involving a secret group somehow living on the Aleutian islands, then learnt that in fact there are such groups, notably the Aleut, of whom there were some 25,000 before contact with Europeans.

So my new answer is that they could escape along the coastline up to North Japan, and then hear tales of a faraway people. After quizzing a few wise old people they might take that path and head along the coast, hopping from island to island. They could well be able to build canoes with a little assistance initially, and eventually (with favourable seasons) make it to the Kamchatka Peninsula.

After perhaps staying there a year with the natives they could continue with assistance from the Aleut all the way to Alaska, making some key longer journeys in the summers, and then make a daring final voyage on to Haidi Gwaii, to the Haida people there.

Answer 15

Here is one of many good references on what it took to design and build a good ship throughout the ages. Cog and Galley

The bottom line is that a band of 30-40 people, many of whom would be youth, are unlikely to be able to design and build a large fully rigged ship.

But by the 1400's, trade throughout the European-Asian continent was prolific. This family was probably quite rich, in order to encounter the wrath of both the Chinese and Japanese officials. But as merchant traders, it would also be reasonable to assume they had European connections. In fact, pre-1400's, China depended on European merchant ships for trade between Japan and China. It is not beyond speculation that this family would have the resources and connections to be able to buy a ship, perhaps even a crewed ship, from European traders. There would be no shortage of available opportunities, given the degree of trade.

See Development of Sailing Ships for a description of Chinese sea ventures under General Cheng Ho in the first half of the 1400's.

Though why they would go East, and not West, would be a matter for your story line to explain. They would have had far better well-established opportunities in India, the Middle East, or even Europe.

However, once they arrived on the Western coast of now Canada, they would have found a very thriving civilization. The Haida were very well established sea-goers, and had quite elaborate villages. Should they be able to establish a friendship, they would survive quite nicely. The Haida, however, were great warriors and quite territorial.

Answer 16

They need an example.

The story as is seems too unlikely. They need to get the idea of crossing, and they need to learn how to build a ship from scratch, learn how to navigate, how to store and save food at sea...

What if, instead, they chance upon an existing shipwreck?

Now they have the source material. They know what the ship should look like, and they can deduce how it should work. Repair is tricky, but it's at least possible. They might find instruments on board that can help them learn to do rudimentary navigation. Barrels that obviously used to store food and water, etc.

This could also serve as the kernel of the idea of escaping to sea.

Note: I'm aware this doesn't meet the criteria for hard science, but I haven't been able to find any actual articles on actual shipwrecks that were re-raised and repaired. I've certainly read stories about them, but I don't think those qualify as sources. I'll try to do some more extensive googling once I get home, all the results I'm finding now are polluted by small boat forums or games that involve ships.

Answer 17

A comment above mentions that the original thought was to start in the middle-east.

Currents in the Indian Ocean flow south along Africa. During the half of the year that the winds are blowing out to the ocean (non-monsoon season), the winds would also take a ship that way.

Rather than rounding the Cape of Good Hope as this same comment mentions, the currents would take you east, south of Australia. Winds and current could rapidly take you to the southern tip of South America. I believe the Kon-Tiki expedition gathered a large amount of fish that had simply jumped onto their raft, so food may be supplemented that way.

The current splits at South America, with part continuing east and part moving north along the west coast. The northward bending Chilean current even gradually slows to almost nothing around 30th parallel (upwelling deep current partially offsets surface current) before picking back up and being diverted back into the Pacific by the "bulge". They might be able to continue in a more coastal hugging manner after that to continue on to Central America.

With the wind and waves essentially pushing you the entire way, you wouldn't need to build complex sails or rudders and would not need to know how to tack and make complex maneuvers.