I am just about to go on a cruiseship for 2 weeks - and they have a HUGE gym . I have never really used ship gyms much - but this time I am intending to use it. I don't really like to use treadmills , stationary bicycles, spinners , etc for cardio exercise - but I reckon I could put my back into a rowing machine. I am just wondering if they come with an inbuilt HRM like many treadmills do?? - or should I take my own??