I don't know their morale and crew numbers. My crew number is 24 and their morale is excellent. The ship I'm fighting (at the moment) is that ship that carries ammunition to Speightstown. But if that is game mechanics then I must say that's utterly retarded.
For starters the stock game didn't have that mechanic so how am I suppose to know that the mod changed that game mechanic. One would presume it would say something in the official documentation. Seventy eight pages and nothing about new boarding mechanics... Oh well, let's read the FAQ. Nope, nothing about new boarding mechanics. Ingame help, lot's of useful information but nothing about new boarding mechanics. Actually that's not the only thing that irritated me, I am really disappointed that there's no comprehensive list of changes of what New Horizons does to the stock game. There really should be that kind of list either on these forums along with FAQ or in ingame help since some changes are explained there.
Now let me say why I think new boarding mechanic is bad. Before I do let me say what I presume (since I don't really know how it works) based on your response. You either can or can't board an enemy vessel based on several variables. Either your crew's morale is lower than theirs or they have more crew members than you or both. If you can't board them there's a chance when you get close that the enemy will board your ship. Now let's list the reasons why that's a bad game mechanic:
1) I AM THE CAPTAIN AND WHEN I SAY BOARD THE ENEMY VESSEL YOU DO AS I SAY!!!
-I suppose I don't need to explain further
2) You are limiting people's choice on how to play the game. If someone likes boarding strategies they can't play the game as a boarder unless they grind gold and buy a better ship that has more crew members. If you have the worst ship with least crew you can't board anyone, if you have the best ship, with the most crew ingame, you can board everyone.
3) The player isn't informed when he can board. I simply don't know how many crew members the enemy vessel has nor their morale. I presume by acquiring a better spyglass I would see their crew numbers and morale so that just leads us to 2) again.
4) This point is more or less implied in 1) but I think I should point it out. It's not realistic. Why shouldn't you be able to board it? You aren't being held back physically by anything. You have your ship, you have your boarding plank, you have your boarding hooks. The only thing that's stopping you are the rules which come from the game code. This point gets even more emphasized if you play in IronMan mode because the point of this mode is "realism".
5) I personally think it's more fun when you can board everyone. I don't really get the idea why you should limit it. I don't see any good coming from new mechanics.
Before I get to the end of this reply I must say that I like the fact you can be boarded. It adds to the realism that there's a chance to be boarded. So if you decide to change the game mechanics I encourage you to leave that.
OK that's it, sorry for the long post but as a veteran player who completed stock game several times and loves the boarding strategy the most , I had to share my thoughts. I look forward to your reply and I would like to know your reasons for putting the new game mechanics into the game.