While there may be an occasional temporary job that you can pick up in season, most employers are hesitant to hire someone for a week or two, or even for a month and then have them leave. While you may be able to get some temp work in the States, if you leave the US temp work is illegal and so you have a pretty slim chance of supporting yourself that way.
The nice thing about developing boat repair skills is that it pays well, there is a big demand in cruising venues for people with skills and often it is a cash trade that flies under the
radar of local governments and so can be very portable.
Jeff