We just got back from a charter where we had a hired skipper. The first night was spent on the boat - the captain preferred to sleep at her place so no problem there - same thing at the end of the charter. Anytime we ate on the boat, we of course provided food and drink to the skipper including any alcohol. We enjoy eating and drinking good food and drink, so i think the skipper enjoyed the meals and drinks we provided. She didn't drink much in the way of alcohol which is what I expected. When we were eating off the boat, she was always invited. She didn't usually join us as I think she liked having the down time without having to make conversation etc. I think it's pretty hit and miss for the skippers when there is no chef involved. Our skipper said that one group she skippered basically lived off Pringles for the week which got old pretty quick! We found it to be much less of an issue than we expected. I also don't think you need to offer cash when you are eating off the boat. They can either come with you, or eat anything out of the fridge/freezer - their choice.