What the title says. If you target a boat with the lazy explorer's telepoof, it'll teleport you to the spot in question... and then you'll instantly drown like the boat isn't there.
The same happens with the c_gonext() and c_gatherplayers() commands.
Attempt to telepoof onto a boat. I've only ever tried telepoofing from one boat to another, so I don't know if telepoofing from a land to boat or vice versa will produce the same result.