After many trips at zee carefully recording CP, I think we have enough data to begin a writeup. I have not explored the separate deck for the Sea of Voices, so I have no commentary for that.
AJE = Approaching Journey’s End
TW = Troubled Waters
In general I will refer to changes in these values by CP in the form AJE/TW (e.g. +7/+4 means +7 CP AJE and +4 CP TW)
Reaching the Sea of Voices requires AJE 7 [28 CP], but locks with TW 10 [55 CP]
Reaching another destination requires AJE 10 [55 CP]
Lashing Waves begins at TW 8 [36 CP]
Fury of the Unterzee begins at TW 10 [55 CP], this is required to hunt a Plated Seal
Steam Prudently is +14/+11 for 5 Actions, and locks at TW 8 [36 CP]
Steam Boldly - Extrapolate (SB:E) from the charts is [either way] +7/+6 or +5/+12, and locks at TW 8 [36 CP]; I presume 60% for an average of +6.2/+8.4
Steam Boldly - Make it up b[/b] as you go is [strongly against] +10/+9 or +7/+18, and locks at TW 10 [55 CP]
Most cards give roughly +3-4/+2-3 on average, with riskier cards giving a bit more AJE and significantly more TW.
Calm Seas: Fair Zailing is better at +6/+4
A Wily Zailor is even better, at +6/+4, +7/+4, or [currently unknown] depending on your experience
Reaching the Sea of Voices
One can simply Steam Prudently twice for 28/22 to reach the Sea in 10 actions. Other options should be compared to this, but see below.
On average, one can Steam Boldly - Extrapolate 5 times before it will lock, giving an average of 31/42; this means one can frequently reach the Sea in 5 actions without cards.
Worst case: SB:E 3 times for 15/36, then SB:M 2 times leaves you at 29/56 in 5 actions, then you need a card to scrub off 2 TW without losing more than 1 AJE, which means either A Corvette of Her Majesty’s Navy with the low suspicion option, one of the Fury menace-reducers, or possibly some of the ship-specific cards I don’t have numbers for. That’s 6 actions + card luck, but you had to be very unlucky to end up there.
Best case: SB:E with good luck and/or A Wily Zailor for 2 actions to get to 14/12 or better, then SB:M for 2 actions for the worst-case +14/+36 to get you to the destination in 4 actions.
For these short trips, other than cashing in on particularly good cards to shave off an action, the cards hardly seem worthwhile, and Steam Prudently is pretty much pointless.
Reaching other Destinations
Again, one can Steam Prudently four times for 56/44 to reach any destination in 20 actions. There’s your baseline for your trips.
Rushing out with SB:E will tend to get you about halfway quickly, as above, leaving you with Lashing Waves. This isn’t terrible, though it means you’ll no longer be able to draw Fair Zailing. In any case, you’ll almost certainly need to use cards to reach your destination.
Remember that you don’t have to get your TW below 10 to reach these destinations, so if you’re nearing the end of your journey with AJE 9/TW 9 you can often make a final push with SB:M regardless of your cards.
Careless zailing or poor luck can definitely push you over 20 actions (looking at my earlier notes, one was as bad as 44), so the prudent option here really isn’t terrible. That said, I completed my most recent voyage in 16 actions, including picking up a Plated Seal.
Other Notes
The good option on A Corvette of Her Majesty’s Navy is the only card I’ve seen (with a Rusty Tramp-Steamer) which simultaneously increases your AJE and reduces your TW (+3/-2). This is very helpful, so I’d say it’s worth getting your Suspicion down before putting out to Zee.
If you’re going after a Plated Seal, you need to get TW up to 10, and you will get +3 TW and have your AJE reduced to 8 when you go for it. On the minus side, you’ll have to deal with the Fury of the Unterzee to get out of there. On the plus side you probably saved a bunch of actions with Steam Boldly getting your TW up. Also, so far the Fury cards appear to be less punishing on failure than they used to be, and some now have an option to buy a success.
Comments, suggestions, and corrections are extremely welcome. I have been updating the wiki as I go, but there’s plenty still to do.