I was looking at Mythic Seas and noticed the spell Winds of Good Sailing stats for 4e (CrAu 5, Sight, Sun, Structure)...
I don't want to copy the text from the book (copyrights and all), but it basically blows a steady wind on a sail for faster, more predictable ship travel.
In 5e, I calculate CrAu30 for the increases in Range, Duration, and Target (Base level 2 +2 Sun, +3 Sight, +3 Structure). This seems like quite a drastic change in level from 4e (30 in 5e from a 5 in 4e) . Does CrAu30 seem reasonable to people here?
Look at similar spells in 5th such as Chamber of Spring Breezes (though you do not need its Unnatural modifier since you are not creating wind indoors). The Target would be Individual and you could use Range: Touch or Voice to reduce it further.
If you are willing to reduce the range to touch, so you could only cast the spell from on the ship to be affected, then it would be the same level as the version in 4th edition (Base 2, +1 Touch, +2 Sun).
The target isn't the ship. The target is the wind. It does not require a size modifier because it is a single weather phenomena (see ArM5 p.125 for the definition of base Individual for Auram spells).
The target is the wind created, not the ship. With range touch the wind would originate from the casting Magus so they would have to be behind the sails. However they would not actually have to be touching the ship as long as they were positioned behind it.
Something to consider is a +1 Unnatural Effect which causes the wind to always shift to blow from the aft to fore of the ship. This would allow the ship to change directions easily while maintaining its speed. Another useful effect is ReAq that controls the movement of the water around the ship. It effectively creates a tide which can move and turn the ship.
In my current game our flagship has enchantments which do both wind and water control with Duration: Concentration and the item maintains concentration. There is also enchantments to control the rigging, keep the ship stationary (anchor replacement), and deflect siege weapons. All combined it can spin like a top, side-slip without effort, stop on a dime, and travel at the maximum speed of a ship with fully favorable wind and tide. We considered a ReHe effect to allow it to move itself but it was much higher level than that required for the wind and water control.
Do you have writeups for the spells that you would be willing to share? I'm also curious how you decided on game effects, such as speed bonuses for the ReAq effect (or upgraded Winds of Good Sailing) you describe.
They are not spells, they are enchanted items. We use a hybrid set of rules for ships with a bunch of it pulled from Mythic Seas, the quality rules from 5th edition, and some oddball stuff pulled from other RPGs.
For us, the boat travel is going to be the basis of one or two adventures (for now), so I just need to answer questions such as, "How long will it take to get there?" and how those answers change given that a magus could cast spells to help the travel.
The rigging control is ReHe Base 3, +1 Touch, +3 Structure, unlimited uses a day which is Level 25. On command it will re-rig the ship in the desired configuration.
The wind creator is CrAu Base 2, +1 Touch, +1 Concentration (item maintains concentration), 6 uses a day which is Level 12. If touching it and concentrating you can change the wind force, from none to the maximum (a stiff wind, not gale force). It is always blowing in the direction the item is pointing. It is mounted inline with the ship, but if you detached it then it is a giant leaf blower.
The water control is ReAq Base 4, +1 Touch, +1 Concentration (item maintains concentration), +1 'Slightly Unnatural', 6 uses a day which is Level 23. If touching it and concentrating you can change the direction and force of the current in contact with the ship.
Concentration duration is important because it allows you to manipulate the effect for the wind and water.
"City & Guild" has a travel time chart for ships on page 89.
Winds of Good Sailing
CrAu 5
R: Touch D: Sun T: Individual
Insert text from Mythic Seas p77
This spell requires the magus to be behind the ship sails as the spell is cast. Note that this creates a wind in a single direction relative to the world, not the ship (e.g. the wind blows North, not from aft to fore of the ship).
(Base 2, +1 Touch, +2 Sun)
Giving it that +1 Unnatural which would cause it to stay inline with the ship would be very helpful. It would save you the trouble of recasting it whenever the ship wanted to change direction, though for most travel that would be rare.
EDIT: Sorry my replies got weird, my cat decided he wanted on my lap and attention now rather forcefully. Dude is 17 lbs of muscle and razor sharp claws so rather distracting.
Winds of Good Sailing
CrAu 5
R: Touch D: Sun T: Individual
Insert text from Mythic Seas p77
This spell requires the magus to be behind the ship sails as the spell is cast. Note that this creates a wind in a single direction relative to the world, not the ship (e.g. the wind blows North, not from aft to fore of the ship). Therefore, this spell would need to be recast every time the magus wanted to change direction.
(Base 2, +1 Touch, +2 Sun)
Winds of Good Sailing and Steering
CrAu 10
R: Touch D: Sun T: Individual
As Winds of Good Sailing, but this spell creates a wind that blows along the ship from aft to fore at all times. Therefore, it does not need to be recast every time the ship needs to change direction. This spell increases the maneuverability of the ship, so long as the sail is kept inline with the wind.
I would think that the Winds of Good Sailing and Steering could help in ship-to-ship combat or other scenarios where the ability to quickly change direction would be useful.
Considering that a great deal of effort in ship-to-ship combat between sailing ships was to position yourself where the wind was favorable to you and a disadvantage to your enemy yes it does. The other guy never has a chance of actually coming to grips with you unless you decide otherwise or are taken completely by surprise.
Combine that with the anchor enchantment that lets you keep your ship in one position despite wind and wave, the enchantment that bounces the first siege attack each round, the fact that the ship carries the maximum amount of siege weapons its size allows, all the charged items it has for combat (many vastly more effect ammo for the siege weapons), and the fact that it will often have both our elite marines and up to two Magi makes it a nightmare.
EDIT: Also even if the wind is in line with the ship, you can still change direction by trimming your sails. With wind that constantly stays in line with the ship your could change direct easier since if you put a slight change from in line to the sails which would normally turn the ship to say 10 degrees from the wind then the ship would constantly be turning at 10 degrees until the sails were trimmed to be in line with the wind. It does require sometime to get used to the changed sailing characteristics which are notably different from normal
One thing a seagoing magus would consider quite valuable are spells that allow their ship to face storms and the waves they cause. What use is speed if you end up sinking in a storm? How better to shake pursuit them safely sail into a storm?