Found this on the website:
For your convenience, gratuities* are charged to your onboard account at $18.00 per person per night* for interior and ocean view staterooms and $22.00 per person per night* for suites. Other staff members may be tipped as services are rendered. As a standard in the cruise industry, please note an 18% service charge will be included on all bar, drink packages, specialty dining, and St. Somewhere Spa & Salon tabs. All gratuities are included for resort stays under our Cruise & Stay programs.
I'm looking forward to the first 5 night cruise on the Islander this coming Tuesday.