Can someone tell me can I make these turns.
My ship have engine capacity of 3 so:
1turn - move forward 3 hexes (speed 3)
2turn - speed lovered to zero
3 turn - U turn or (U3, 1U2, 1U1) (0+3, 0+3, 0+2)1turn - move forward 3 hexes (speed 3)
2turn - speed lovered to zero and U turn (3+0, 0U)
It depends on your speed in the previous game turn.
1 hexside turn = Thrust requirement is greater of last turn or this turn's speed
2 hexside turn = Thrust requirement is sum of last turn and this turn's speed
3 hexside turn ("U turn") = Same as 2 hexside turn
Assuming your speed last turn was 3, and your engine capacity is also 3, then you are allowed to make a 1 hexside turn and still move up to 3 hexes. You may also turn 2 or 3 hexsides, but in doing so your ship must come to a stop.
So yes, your calculations are correct, presuming your previous speed was 3.