Zailing Advice: Extrapolate or Steam Prudently?

I’ve been zailing back and forth between London and Hunter’s Keep for a while, and I can’t help but wonder what the benefit of the Steam Prudently option is versus the worst-case scenario from Extrapolate from the Charts. In my experience, steaming prudently has almost the same effect as failing an extrapolation, which seems counter-intuitive (why not just extrapolate all the time, then?).

Has anyone actually crunched the numbers to see how each option affects your progress? I’d like to see if my hypothesis (pardon the pun) holds water.
edited by MrUnderhill89 on 5/15/2014

The wiki is your friend:

Ah, I didn’t see that they had the change rates up.

To sum up, it looks like I wasn’t far off. Here are the change rates listed side by side:

	 	 	 	 	 	    [table] 	 	 	[tr] 		[td]Option 		[td]Progress (Success) 		[td]Trouble (Success) 		[td]Progress (Fail) 		[td]Trouble (Fail) 		[td]Success Rate 		[td]Progress (Average) 		[td]Trouble (Average) 	 	[tr] 		[td]Steam Prudently 		[td]1 		[td]2 		[td]1

[td]2 [td]100.00% [td]1 [td]2 [tr] [td]Extrapolate from the Charts [td]2 [td]1 [td]1 [td]3 [td]50.00% [td]1.5 [td]2 [/table]
So extrapolation really is the better option. Even if you fail all the time, you’ll make just as much progress as steaming prudently; you’ll just have a higher Troubled Waters score at the end (and Troubled Waters hazards aren’t that menacing, anyway).
edited by MrUnderhill89 on 5/15/2014

Extrapolation is, on average, the better option. Keep in mind that that’s an average, and thus dependent on not having a string of harsh luck. ;)