I have never had a skipper for a charter with exception of a check out skipper for a day.

The charge for a skipper with TMM is $175 per day, which according to their website, all goes to the skipper. So for a 7 day charter, skipper receives $1225 as part of the charter.

Gratuity suggested and

In TMM's Skipper FAQ section:

{WHAT IS THE TYPICAL GRATUITY?

Skippers work hard to provide the best possible service to their clients. If they have done a good job for you, they will appreciate a gratuity at the conclusion of the charter. A rule of thumb is $350-$500 for a one week charter. A one-day Check-Out Skipper (COS) gratuity would be a percentage of the fee of $175. Twenty-five dollars tip for a COS would be a good rule of thumb. All gratuities are optional.}

So skipper is receiving, based upon these guidelines, $1575-1725.

I think this is reasonable, especially if including him/her in shoreside meals/drinks. I could also see tipping beyond this recommendation if he/she is exceptional.

AT TIME OF BOOKING, I would suggest asking about recommended gratuity. The captains who serve as skippers for various charter companies probably have expectations based upon how each company handles skipper fees.