Increasing turn speed

[Ruatha]

In NGC2 turn times where generally fast. In NGC3 they where fast in the beginning. (Both games 20 players).

Now at turn 35+ the speed is far from impressing, not that the empires are big and hard to handle. I guess RL issues play a part.

The turn deadlines are 72 hours, this is to allow for shorter leaves without missing a turn.
The problem is that once the turntimes started to increase more and more players have started to delay sending in turns, it's a downwinding spiral....

I wish to retain 72 hours turntime but to increase motivation to speed up the turntimes, but how?

I'm starting a "Turn submission league" in the game where the first three players to send in the turns get +1 points, the Last but one gets -1 and the Last player gets -2 points (Not submitted turn = -2 pts).

I'm not sure this will have any effect but it's worth trying.

Does anyone have any other suggestions to motivate people, preferabbly "nice" motivators and not threats or punishments?