Good Day Captain, I watched lots of Video regarding this topic. you have explained this briefly with good animation , and i understand fully . Best part when u pointed out about relative motion not to make officers confused in collision avoidance I hope i can be a captain as you one day .
Sir your explanations are really great and easy to u derstand... still now i had never seen such a great explanations...with animations...pls i humble request u to do more videos...for example...gyro and magnetic compasses...anchoring procedures...steering gear..ordering of charts in ecdis..etc thank u very much for spending your valuble time
Can you please make such videos on gyro compass and magnetic compass , working and mechanism, errors. It would be helpful for your subscribers and other viewers for understanding the concept.
thanks for sharing this knowledge sir.. from the ROR explanation, where can we find out the speed of the current? does that mean the difference in speed read by the gps and speed log can be said to be the current speed? there is a situation on a ship anchored or moored, speed log reads speeds of up to 5 knots, what speed is being read by speed logs? or my speed log in error?
Hi Aldo. 1) For an understanding of the ROR situations, you need to know the aspects of the vessels, how they are approaching each other, not the current speed. Modern radars today display the speed & direction of current too. You can visualize the current direction and speed by drawing vectors of the gyro course, course made good & wind which is the major contributing external force in a drift along with current at sea. 2) Yes, the difference in GPS and log speed can be used to measure current/water mass speed. Pls, try to visualize this by taking into account the components of the vector of the current in the same direction ie the ship's heading. An upstream or downstream direction of the ship will give you strait calculation of current, as explained n the video but if the current is from an angle then the vector component in the direction of the ship's course comes in the calculation. 3) It the ship is anchored or moored, then it becomes stationary to the ground and your log gives you the speed of water mass/current. Remember, your SOG or GPS speed will be 0 in this case. If at anchor, your speed log is 0 and you have some GPS speed (ignoring the moments of swinging) then you are dragging anchor or drifting with the current. Speed log gives you speed through water but modern doppler logs have dual axis bottom track speed too and they can tell you speed over ground too. In fact, you can select one of the 3 modes to have speed over ground, through water or automatically select it which it does, depending on the depth. For speed through water, the depth below keel should be more than 3 meters to have correct readings. Below 3 meters, readings of the log can have errors.
Thanks alot sir , How about tails sir ?? Trails give me history of my vessel course . But there is true and relative trails ?? Please explain me sir ?? Which one to use when ?? Thanks alot sir
Good morning to you, Aspect , will it be same for course and speed obtained by manual plotting , since course will be true course ,not heading, awaiting your valuable reply, Thank you
Sir! If we are in ground stabilised mode and using relative vector.... and current is against us... and it will reduce the SOG.... then will it affect the length of relative vector??...Sir can you please answer
When using relative vector, vector will be shown on target objects, not on own vessel. So the length of the vector depends how the current affects the target. As both the vessels are in same water and affected the same way, there won't be any change in length of vector. Suppose if the target is a fixed object; as our speed reduces, the relative vector also reduces...
im a student sir and i have a question. is ground speed is same like speed over ground? and is surface speed same in speed over water? i hope it will notice
