Getting Captain Lisence

[ImASonOfaSailor]

Can anyone help me with this question your postion at L 37 11.6N Lo 75 46.8 w at 0850, youplot a course for the Mid channel Bouy Rw A mo for sandy Shoal inlet at a speed of 8.3
i have to find True course, the course PSC, compass error
and the ETA to buoy

i need help to understanding it

[puddinlegs]

Are you a non-native speaker and this a language issue?

[Boasun]

Draw a track line between the fix and that buoy... walk it over to the nearest compass rose and read the outer ring. that will give you your true course.
Apply variation for magnetic and enter the deviation table with M and find the deviation and apply it to magnetic and you will have PSC.
Compass error is variation & deviation combined.
The length of the track line is a distance which is divided by your speed to find time for that leg and add to your start time for ETA.

[ImASonOfaSailor]

WOW cool thanks! I think i can do this now! Thanks Captain!

[dnf777]

Originally Posted by Boasun

Draw a track line between the fix and that buoy... walk it over to the nearest compass rose and read the outer ring. that will give you your true course.
Apply variation for magnetic and enter the deviation table with M and find the deviation and apply it to magnetic and you will have PSC.
Compass error is variation & deviation combined.
The length of the track line is a distance which is divided by your speed to find time for that leg and add to your start time for ETA.

How do you account for compass deviation on a boat? My understanding of CD is that it only occurs when turning to/from N/S or accelerating on EW. In any case, once you're established on course, the deviation abates, and shouldn't be a factor. Right?

[flyingwelshman]

Originally Posted by dnf777

How do you account for compass deviation on a boat? My understanding of CD is that it only occurs when turning to/from N/S or accelerating on EW. In any case, once you're established on course, the deviation abates, and shouldn't be a factor. Right?

My understanding is that deviation is constant - and varies depending on heading. It is specific to each vessel and requires preparing a deviation chart (showing the deviation at each heading) to more accurately produce TVMDC corrections or uncorrections.

[ImASonOfaSailor]

You would need a deviation Table Degree form your area that ur at! You should get those where you would get your updated chart from and you should get a Tide table also while you are there...

Ok I am have a hard time in subtracting 2400 time and adding is there a way you guys understand this better? Thanks

[lickingcardboard]

2400 is midnight 2100 is 9Pm 2100 hrs -12=9
All times after 1200(noon) -9 to get this PM hour.

[flyingwelshman]

Originally Posted by ImASonOfaSailor

You would need a deviation Table Degree form your area that ur at! You should get those where you would get your updated chart from and you should get a Tide table also while you are there...

Ok I am have a hard time in subtracting 2400 time and adding is there a way you guys understand this better? Thanks

The 'Variance' (magnetic declination) is geographically specific. The variation, including annual adjustment can be found on the compass rose on a chart.

The deviation is specific to each vessel and has to do with the effects of the boat's structure, or systems (electrical etc.), on the compass. The deviation will be different for each heading. To find the deviation involves sailing along known headings and establishing the difference between true and compass bearings. Once variation is accounted for the difference is deviation. This will change for every heading, so the process has to be repeated until you have established a deviation for each heading. This information should be charted and is used to do your TVMDC calculations.

There is an article on this HERE.

[Boasun]

Deviation is the magnetic signature of your vessel. And as you change course the deviation will change. This is why you have a deviation table/card.
There are a couple of tricks to ensure that your deviation card is correct. They are easy. But having a compass adjuster swing your vessel for the first time is so much easier. Takes about a tad more then a half a day to do it.