Was this intentional? It takes longer than removing car engines?!
Talking about things that take surprisingly long, there’s the time it takes to remove the last frame from nothing at all. You’d think when the vehicle was only one frame with nothing attached to it you could just pick it up - but no, you gotta get out the hacksaw. 
Checking json files, hand paddle is set to removal of 60m, where as the engines are all 30m. Perhaps it’s because of the engineering feat involved to integrate it into a vehicle system?
In that situation I would create a custom mod to change the value to something that makes more sense to me.
realistically, installing ‘hand paddles’ as an engine option is as simple as having two clamp points near the edges of the boat (think rowboat), or as INCREDIBLY simple as ‘this is a paddle, you dip it over the side of the boat to move forward… when it is not in your hands it is on the boat.’
hence, definitely shouldn’t take more than a few seconds to install/uninstall in either case.
Actually, I was thinking foot crank and being able to engineer that in. That takes 30m removal. Yeah does seem over estimated.