they are rubber hose/channels that your driveshaft is going threw. They go from your transom to your outdrive. more will chime in. Do you have an inboard/outboard
#13 is the watertight connection between the gimbal housing and the movable bellhousing that the outdrive attaches to. #19 is the exhaust bellows that directs the exhaust gasses out from the gimbal housing to the exhaust ports in the outdrive
#26 here is the shift cable bellows that keeps water from leaking in around the shift cable http://www.mercruiserparts.com/Show.../5.png&inbr=1017&bnbr=30&bdesc=GIMBAL+HOUSING
This is for a Mercruiser,but the principal is the same with others. They are used to make a flexible connection.
Yup the drive comes off.While it's off change the shift cable and bellows and make sure the gimbal bearing is good.Then change the impeller and oil.
It's actually easy to do.Just take pics as you disasemble.J
