There will be one on the boat. You could try calling the base to see if they could send you a digital copy somehow.

But to be honest, there's not a whole lot you'd get out of reading it ahead of time - unless you can read something once and have it memorized. For starters, the boat briefing will go over all the common stuff. If there's any issue that came up during the trip you could review the manual for tips, but often its easiest to call tech support and have them walk you through it or send someone out. Given that it is your 8th charter, if you've been on the other model cats (4600..etc) many things are very similar, just in slightly different places.

Personally, on my boat I'd rather someone call tech support than try to fix something they may not be familiar with.