diving planes to the front because they have more control there than on the sail, also its quieter but does come at a price you loose some sensativity in the soar due to water flow over the planes.
the 688 was hard to surface through ice because of the planes and they were also prone to being damaged while coming alongside (look on bills site the picture), what could happen is come along side and the plane would hit the side of the ship either bending or breaking it.
also the dive planes on the sail over hand the side of the sub so thats how the above happens.
during high speed you can retract bow planes you cant retract sail planes so if the helmsman stuffs up and pushes the wheel forward you go down cant happen if bow planes are retracted
thats why russian high speed submarines put them on the bow and not the sail
