Honestly I am not sure how to "change" the volcanoes.
Frankly from a functional standpoint I do think they are fine (certainly still a challenge if your caught off guard, compared to how OP they were initially - and that was BEFORE they added more complex ship damage and fire.)
As to the Voyage halting thing, I think alot of it has to be the length of time that the eruptions last.
I mean take yesterday. I was on the live build doing DR cargo runs, I got unlucky and the outost began erupting when I pulled up. (Caught me off guard right?) While my ship did not sink (though it certainly came VERY close), the eruption lasted almost 6 minutes.
Another instant was on the way to Fetcher's Rest, the island was already erupting on my journey there, and when I was close enough that I had to stop, it was still going. The journey from Morrow's to Fetchers was about 3 minutes and then another roughly 5-6 minutes, before it stopped.
During the Crews of Rage, Molten Sands Fort, would sometimes erupt more than once with only a 3 minute reprieve between roughly 2 separate 5-6 minute eruption. See what I mean?
Call it a nerf if you wish, but frankly the TIME at which the Islands erupt seems to be more of the issue. Though I dont mind if the frequency remains the same, but while it may not seem like much on paper; in practice doing NOTHING for 5-6-near 10 minutes is quite a long time from a gameplay perspective.
I guess on that note, if I WERE to suggest a change, it would be, Make Each island Erupt every say; 10 minutes, but make each Eruption last 3 minutes max.
The timer would start from the eruption, so it would essentially mean each island would have 7 minutes of "safe" time so to speak. And it does not need to just be an eruption. It could still rotate between a chance at eruption or quakes. Make it a 50 50 split, so that eruption would still be present and a worry but not so lengthy that they cause voyages or progress to come to a halt so often.
I.E:
- Game rotates a RNG 50% split of Either a Quake or an Eruption Every 7 minutes
- Quake/Eruption begins, resetting the a 10 minute timer
- Quake/Eruption lasts 3 minutes
- After 3 minutes, quake eruption ends, leaving 7 minutes before the next eruption
- Go back to step 2 after 7 minutes
7 Minutes of free time, 3 minutes of Danger for a solid 10 minute rotation in the Devils Roar.