NathanDeAlien

0= 1*(9-9)*4... ........................ Grmal
1 = 1994
2 = -1-9/9 +4.. .........................Melody
3 = -1-9 +9+4.. ....................... Melody
4 = -1+9/9+4.... .........................Melody
5 = ceiling [ (-1+9) / 9] + 4... .....Melody (I am cheating a bit here, ceiling means find the answer and round it up to the nearest whole number)
5 = 1+9-9+4...........................Demogorgon
6 = 1+4+9/9...........................Demogorgon
7 = 19-(9+4)...........................Demogorgon
8 = sqrt(9)*sqrt(9)-14
9 = 9*149
10 = sqrt(9)*sqrt(9)+14
11 = 9+sqrt(4)*14
12 = 9+sqrt(4)+14
13 = 9+9-(1+4)...........................Demogorgon
14 = (9+9-4)*1...........................Demogorgon
15 = 1+9+9-4...........................Demogorgon
16 = 9+9-sqrt(4)*1
17 = 9*4-19...........................Demogorgon
18 = 9+9*14
19 = 9+9+14
20 = 9+9+sqrt(4)*1
21 = 9-1+9+4...........................Demogorgon
22 = (9+9+4)*1...........................Demogorgon
23 = 9+9+4+1...........................Demogorgon
24 = (9-14)*sqrt(9)
25 = (99+1)/4...........................Demogorgon
26 = -1-9+9*4 ... .......................Melody
26 = 9*4-(1+9)...........................Demogorgon
27 = 9*4*1-9...........................Demogorgon
28 = 9*4+1-9...........................Demogorgon

29 = (9+1)*sqrt(4)+9 

Anyone care to join in using some more computations? 


30 = 49-19...........................Demogorgon
31 = Ceiling [sqrt(991)^1].........NathanDeAlien

36 = 9(9-4-1)...........................Demogorgon
37 = 

39 = 49-(9+1)...........................Demogorgon

40 = (49-9)*1...........................Demogorgon
41 = 4(9-1)+9...........................Demogorgon
42 = 91-49...........................Demogorgon

44 = 9(9-4)-1...........................Demogorgon
45 = 9*4*1+9...........................Demogorgon
46 = 9*4+1+9...........................Demogorgon

48 = 49-1^9.........................NathanDeAlien

50 = (9+1)(9-4)...........................Demogorgon

54 = 9(9-4+1)...........................Demogorgon

57 = 9-1+49...........................Demogorgon
58 = 99-41...........................Demogorgon
59 = 41+9+9.........................NathanDeAlien
67 = 9*9-14...........................Demogorgon

68 = 9(9-1)-4...........................Demogorgon

75 = 94-19...........................Demogorgon
76 = 9*9-1-4...........................Demogorgon
77 = 9*9*1-4...........................Demogorgon
78 = 9*9+1-4...........................Demogorgon

84 = 9*9-1+4...........................Demogorgon
85 = 9*9*1+4...........................Demogorgon
86 =9*9+1+4...........................Demogorgon

94 = 99-4-1...........................Demogorgon
95 = 9*9+14...........................Demogorgon
96 = 91-4+9...........................Demogorgon

98 = 99-1^4............................NathanDeAlien

100 = 99+1^4

That's what I got and I think that you're just over complicating it!

The answer is 262941862

The part of the question 'stillwater and current' can be interpretted to ways:

1) The current is pushing him in the right direction getting him a time of 2 hours.

 OR

2) The current is pushing against him getting him a time of 4 and a half hours.

I would guess that the question is refering to the view 2. So all you have to do is 18m divided by 2hrs and 18m divided by 4 and a half hrs. Getting 9m/h for still water and 4m/h for fighting against the curent.