## NotTim 3 years ago A boat is travelling at 18 knots on a heading of 234 degrees. The current is 8 knots, flowing from a bearing of 124 degrees. Determine the resultant velocity of the boat.

1. NotTim

I got the speed, its 22 knots. But I didn't get the angle.

2. NotTim

The correct angle is a bearing of 254. I got 19.9 degrees.

3. NotTim

to get such an angle, i used sin^-1(8sin110/22.056)=Angle

4. NotTim

to get my speed, c2=8^2-182-2(8)(18)cos110

5. NotTim

um...anyone got a response?

6. dumbcow

everything looks correct, again the 19.9 refers to the angle inside the triangle the new bearing will be 234 + 19.9 = 253.9 which is slighly different from answer given ? not sure why

7. NotTim

this txtbook rounds the answers. How do I know whether to add or subtract from the current bearing on which the angle/point lies?

8. dumbcow

|dw:1333624601334:dw| use the diagram

9. dumbcow

if the current was flowing the other direction then you would have subtracted

10. NotTim

|dw:1333635586620:dw| wait...thats not a bearing...

11. NotTim

unless I draw my diagram wrong.

12. dumbcow

oh are bearings supposed to go clock-wise? sorry sometimes i forget navigational convention

13. NotTim

but it still works eh

14. NotTim

bearings start from the top and go clockwise, yeah

15. dumbcow

haha oh well but the math will still work out the same because its all relative to your starting position :)

16. NotTim

ok. thank you very much! you helped me just in time!

17. dumbcow

welcome