I have a 278 that was built in 2006. I can disconnect the electric hatch lifter and lift the hatch beyond its normal range of travel. Also, I have taken the engine hatch off twice - once to work on the hinges and once for an engine removal.
To remove, lift the hatch and disconnect the electric lifter (pull the pin at the top end). Disconnect the water pipes to the swim platform shower. Lower the hatch back in to the horizontal position. Remove the visible screws that hold the hinges down to the swim platform. Lift the whole thing off with a couple of strong assistants. The second time I took the hatch off was in a boat yard and a fork lift was used for the lifting as it was also needed for the engine.
