Use of yacht photos

Hi. We are developing http://www.crewheadhunter.com and have a lot of photos of luxury yachts that we would like to use on the site. Some of these were taken by me and others by friends. We do not have a clear understanding if we can use photos of yachts without permission of the owner or captain. If anyone out there cares to comment on this, that would be very helpful... Thanks... MD