Why does the ship need to change course? Set the course in the morning and cast the spell once, it lasts until Sunset. This ship doesn't need to visit ports or hug the coastline in case the winds aren't favorable. The winds can and will always be favorable.
- Avoid an island, sandbar, or underwater rock (those do pop up in the middle of the ocean).
- Investigate a ship, sea monster, wreckage, or mid-sea regio
- Avoid a ship, sea monster, wreckage, or mid-sea regio
- Go around a cape or peninsula
- Swing around to pick up a sailor who'd fallen overboard
- Simply adjust your course.
Yes, adjusting course would be necessary. Navigation by the stars is dependent on weather, navigation by dead reckoning is extremely unreliable when you don't have a precise time-keeping device, and both suffer greatly from the absence of precise maps. Plus, your compass is a needle stuck to a bit of cork, floating in a bowl of water. So if you're off by as little as 1 point of heading when you set your course in the morning and simply run in a straight line, by the end of the day you're 16 miles from where you think you are... and that's before you take tides or ocean currents into account. That's another reason most ships hug the coastline: they can't tell where the heck they are otherwise.
And the reason I asked whether the wind veers with the ship is actually none of these. 
It's something that Tearlach wants to talk to Talia about, because he does see her casting it every morning as a problem... I just don't know how big a problem it is yet.
Talia can cast it as necessary. Given that she's always been the captain and in touch with the navigator, this hasn't been an issue before. If Tearlach needs to make a course correction he's free to request one from Talia, and she'll oblige, no muss no fuss. This isn't anything different than what she'd been doing before when her first mate ran the ship on the way to Verdi, I suppose.
I'm guessing that you have a Cog since it is very very common in this time. There are no top sheets or Spanker sails on a Cog
globalsecurity.org/military/ ... ip/rig.htm
((And the title Commodore would not be invented yet))
jebrick is a age of sail geek 
I know. Doesn't make the pun any less funny, though.
I said OOC that Commodore was an anachronism. Gotta better term? 
For what the crew would call her or the Captain/master
Incidentally, thanks for the link. I've been using Falconer's as my reference, but it's both out of period and damned hard to read.
"The Tytalus was exceedingly vexed
When they told her she was oversexed.
She said, 'That's not true,
I just like to screw.
Now please take a number. Who's next?'"
Sun kissed skin so hot it'll met your popsicle...
I really don't think that's a fair comparison. I am not an ST:TNG expert, but as far as I know Picard couldn't take care of most of the crew's tasks by himself with the push of a button.
Most of the work on a sailing ship has to do with actually managing the sails in response to wind changes. "Spell of fair wind" means there aren't any wind changes: you can set your sails and just keep going. Talia's other enhancements just add to that. To make sailors work as hard as they would on a non-magical ship, Talia would have had to give them make-work.
You raise a fair point. But you're also changing the discussion, very subtly. I'll bite and answer. My understanding of the scene, so far, is that Talia has been casting A Spell of Fair Wind since departing Verdi. She, Aodhan, and Tintavius I presume, intend to be back to Scotland in time for Tribunal. She may not have communicated the why for wanting to get back to Scotland to Tearlach, but she would be crystal clear about the need for speed. So, the drills that Tearlach has been running the crew through are just another form of make-work, if we accept your contention as a player that having Talia control the wind does all the jobs for a sailor. Now, Talia probably has given the sailors make-work to keep the men busy and occupied in the past, but there are always other tasks to be completed aboard a ship other than sailing. Yes, her spell makes the task of sailing the vessel significantly easier, but until now, I've been dealing with the crew as an abstraction, we now have a situation where we need to be more specific about what the crew does, and it's actual size. Talia doesn't always take care of the crew's tasks at the push of a button, the only thing she is doing once Tearlach is captain is directing the wind, because she must. Tearlach doesn't have a choice in this matter. And the crew is undersized for a medium cog, I said that in character to give you an idea of the challenge you're facing, after Talia is no longer aboard. This isn't exactly the best time to figure out what the crew is made of, and whether they can operate without Talia. Talia's just making it crystal clear that now isn't the time. So, in many ways, what she did was necessary just to make the ship operational. Couple that with her ability to fire a vessel from afar (Creaping Oil followed up with a Pilum of Fire) and any piracy they did engage in was probably relatively easy to accomplish/
So, going back to what she did to Tearlach, she did what she did as a lesson to both the crew and Tearlach. Tearlach is the captain. If she didn't want him to be the captain, he just wouldn't be, anymore. It's just that simple. She wanted him to observe the crew more closely, and she wanted the crew to understand that he was being punished on deck for a reason. She has punished her crew before, but most of those punishments involved a removal of the carrot, so to speak. Tearlach may feel that the crew loses a measure of respect for him, but since I've been the one who's handled the crew and has sketches of their personalities, they find that this is an interesting occurrence, that Tearlach is going to be a captain of this vessel for the foreseeable future, and they better get used to it. Also, if this is a kinda-sorta pirate vessel, captains are traditionally elected, so Talia appointing Tearlach as captain violates some of the rules...
I suggested the Picard/Jellico thing, just because it's a change in command. It isn't an identical situation, by any means. It's just bad form for a previous commander to complain to the past commander how he ran the ship. The previous commander can't change anything, and probably wouldn't want to change anything. You're just dealing with someone who owns the ship, and Tearlach may not know this, but she made the ship, too boot. That, she she's hand picked this crew, and has been with them for years. Finally, the last point, is that I wasn't done with the scene when she had ordered Tearlach lashed to the mast. I was just opening it wide open for other characters to comment on Tearlach's situation. You wanted a scene, you didn't set any expectations for the scene. 
From the peanut gallery... The spell does not mean you can't wear and tack the ship as needed. It makes a wind blowing in a direction. For a cog, with one square sail, it is helpful but only for long runs where the wind is astern. A single mast, square sailed ship handles like a pig. IIRC, they would have a small crew. Perhaps 6-10. You could pack it with men if you were a pirate or were scared of pirates.
The command situation would be interesting. There is no "captain" at this time for these vessels. Everyone works. The equivalent would be the ships master who would be in charge of most sailing decisions. He would give way to the owner of the ship. The Navigator would be the other important person. At this time, most ships were coast huggers that did not need a navigator.
So the crew would know Talia is the owner and would ( if they were crazy superstitious) defer to her. I'm guessing her title would be Lady if a title is needed.
And what happens when Talia can invest an effect that just moves the ship with ReHe? No need for sailors then...
As a player, I think there's more to explore here. Wasn't going to let the scene end so easily...
True but how many men want to be on a ship with a woman in the first place? And unless they were all automatic, why would she want to have to cast a spell everytime a rope needs spliced or joint caulked.
Not knowing the ship, I would assume it is about 100 tons, which would be about right for a small Cog. Looking it up in Mythical Seas, it says crew of about 35.
Okay. Couple of points.
First of all, I agree that Talia's response is entirely in character. I wish she hadn't done that because of the implications going forward, but that's a separate discussion.
Secondly, I think the basic issue here is that you and I (the players, not the characters) have a VERY different view of what life on the sea was like. I'm an age of sail geek, like jebrick, and honestly, my reaction to most of the things you've said about the ship and the way it's run is "Wait a moment, this wouldn't work." (I can elaborate with examples, if you want, but that is, again, a separate discussion.) So I think us not being on the same wavelength OOC is a large part of why the characters are not understanding each other IC.
I designed Tearlach to take advantage of that knowledge I possess. I like diving down into the "what was this REALLY like" mindset. Problem is, if I do that, we're going to keep butting heads.
This is where good drama and story come from. I don't object to PC conflict. And I don't object to Talia being taught a lesson later on about how what she did now was short-sighted. People make mistakes, it's one of the few things you can count on, besides death and taxes.
Perhaps, but Talia's issue wasn't with life at sea. It was about overall command. OOC, I may have some different ideas of how things worked, but my understanding matched jebrick's, pretty much. A small crew of 6-12 men is all Tearlach has, and most of the work is done by pointing the ship in the desired direction, and then making the wind blow in the same direction. Repeat as needed. There probably were times where Talia didn't use her spell, but this isn't going to be one of them, so again, it comes down to the fact that if Talia was making the wind blow in the desired direction previously and was doing it on the return trip, both captains were giving the unoccupied crew make-work. Right now, Talia doesn't give two shakes what Tearlach wants, her needs trump his as ship owner. Again, I have some ideas for some interaction that will put her actions in a slightly different light and may illuminate how the crew feels about this transition.
I think you're missing the point. Talia was captain by necessity. Her need to steer the boat now, to continue under-utilizing the crew is also of necessity (to ensure she's back for Tribunal, for which a thread she's participated in has already started). Tearlach is caught between the wind and the sail, right now. After Talia's back in Insula Canaria, she can focus on building the shipyard, while Tearlach focuses on manning the other ship(s). I, as a player don't have a huge interest in running a "captain" so much as I have an interest in building a Hermetic shipyard with a sub-optimal character, i.e. not a Verditius. Talia would never delve deep, like Tearlach would. She'd just work some magic to solve her problem and move on.
I must admit, I totally did not see that coming.
Oh, by the way...take a "You amuse me" point (basically, 1 xp to be applied to any of your characters).
Thank you.
When I was running 7th Sea (which hands out Drama Dice for dramatic actions, witty banter, etc), I used to have a standing rule. If you can break the GM (i.e. make me burst out laughing) you get a Drama Die. I had to cancel that rule after we figured out that I was spending more time holding my sides than actually running the game.
Honestly, that's always been my issue with Items of Quality: there simply aren't that many items that someone would use that also have a directly applicable shape-based bonus. And it also has to be something that affects Tearlach and not the ship as a whole, since those enchantments would likely be Talia's bailiwick.
Astrolabe -- bonus to Navigation. Helmet -- bonus to affect sight. Aside from the standard "armor/sword" type of stuff that's all I can think of.