Hi William - We have had an increasing number of inquiries about integrating the Nautical Monkey tools into an existing boat sharing business / web site and have actually started development on such a system.
The idea will be to provide a "branded" subset of our tools - scheduler / calendaring system, communication tools, mobile check on / check off functionality, service requests, etc - as a plug in to your existing web site. From your user's point of view, it will look like you are providing the tools and functionality yourself which should not only increase their confidence in signing up with you, but will also give them a solid set of sharing/calendaring tools to use once they do.
If you are interested checking this out before it's released or would be interested in integrating this kind of functionality into your web site, let me know and I'll include you on the beta list for testing and updates.