First things first, update on son. It has been two and a half weeks since the surgery, and things are definitely looking much better. We saw the surgeon today, and he is quite pleased with how things are healing up. The incision is closing up from the inside noticeably, with no sign of any infection. It just looks like it will be a slow but steady healing process, with my wife and I getting very good at dressing changes. I am not sure if the moderators would appreciate a picture of the canyon being posted here, but my son has me taking a couple of new photos every night so he can see how things are going. It is a tad hard for him to see his lower back. Thanks for all of the concern shown.
Next, @ Blue Monkey:
I was going through the Oxford Atlas of Exploration a couple of days ago, and they were using the terms "double hull" and "twin hull" interchangeably to describe the Polynesian colonizing canoes. I suspect that is also the case with respect to the modern replica, with the mention of "double hull" meaning a catamaran with two hulls, and not a "doubled hull" as you would have on a modern oil tanker.
@ Ozymandius:
I posted this on another thread, but as it has considerable application to your mod, I will ask the moderator's indulgence to post it here as well.
Yes, working within a limited time period, in this case, the Age of Sail, makes it much easier to have a greater range of ship speeds for sailing ships than if mechanically-propelled vessels are included. A larger sailing ship has two speed advantages over a smaller ship.
The first is the benefit of a greater speed-length ratio over a shorter vessel. Wave making resistance for a ship increases drastically once the speed in knots exceeds the square root of the ship's length in feet. For example, a ship that is 100 feet long traveling at 10 knots has a speed-length ratio of 1. To increase the speed of that vessel to say 12 knots, or 20%, will likely take an increase in power on the order of 44%, the square of the speed increase. Unless steps are taken to reduce the friction resistance of the hull, which is roughly proportionate to the speed of the ship, the actual increase in power needed can easily reached the cube of the increase, so for a 25% increase in speed, the additional power required can be 200% or double the power for 10 knots. A World War 1 US 4-piper destroyer required 3,000 horsepower to reach 20 knots in speed, while it took 26,000 horsepower, nearly 9 times the power, to push the ship to 36 knots, a speed increase of 1.8.
The second advantage of the larger ship is being able to carry a heavier spread of sail under any given wind condition, so that as the winds grow stronger, the larger ship can maintain a greater sail area than a smaller ship without becoming unstable. There are many cases of a ship-of-the-line running down what would normally be a smaller and faster ship, in lighter winds, when a gale or near-gale was blowing, as she did not have to take in sail. There are also a fair number of instances where the smaller ship ended up capsizing from carrying too much sail while attempting to escape.
When you combine these two factors, it is fairly easy to justify giving an East Indiaman nearly twice the movement factor of a caravel, say having the caravel move at 6 and the much larger East Indiaman move at 9 or 10. Then a Seafaring nation gets a +1 bonus from having trained seamen able to get that much more performance out of a ship, with the boosts from a Navigation School and Magellan's voyage being viewed as coming from more efficient rigs and better hull design and also a much better understanding of the wind and current patterns to gain shorter voyage times.