[MrA]

Mr A - what is the true bearing from the monument to the lookout tower.

like tempest I get 60T

 

[jackdale]

Solution

T bearing monument to lookout = 060

V = 15W (from my chart - is training chart different?)

M bearing monument to lookout = 075

D = 075 - 070 = 5 E

C = 300 (ships compass) +130 (relative bearing from pelorus) - 360 = 070

So how many of you have a pelorus on board?

 

[jackdale]

https://www.flickr.com/photos/[email protected]/sets/72157648133603306/

I'm using chart 1210Tr...thanks davidpm, rgscpat, jackdale and tempest for helping me thru this, questions are 7 & 8 in the above link.

My chart shows only one tower

What is the true bearing between the towers?

Jack

 

[MrA]

Solution

T bearing monument to lookout = 060

V = 15W (from my chart - is training chart different?)

M bearing monument to lookout = 075

D = 075 - 070 = 5 E

C = 300 (ships compass) +130 (relative bearing from pelorus) - 360 = 070

So how many of you have a pelorus on board?

thanks so much T was the key

 

[MrA]

My chart shows only one tower

What is the true bearing between the towers?

Jack

I get 359T

 

[jackdale]

The solution

T = 003

V = 15 W

M = 018

D = 3 W

C = 317 + 064 - 360 = 021

 

[MrA]

The solution

T = 359

V = 15 W

M = 014

D = 7 W

C = 317 + 064 - 360 = 021

I get a different answer.[/Quote

Yes, I get the same, I'll double check my line and make sure T was 359, I see what I was missing in your solution thanks

 

[tempest]

3 W is correct...the line is 003 deg.. not 359

 

[tempest]

I had to put my reading glasses on..for this

 

[jackdale]

I had to put my reading glasses on..for this

My glasses are an aid to navigation.

Thanks for that. I will edit my post.

 

[MrA]

3 W is correct...the line is 003 deg.. not 359

I tried again last night, best I could come up with 000T, I will draw a thinner line a put on better glasses and see what I can come up with thanks

 

[rgscpat]

I believe a one-degree bearing error at one nautical mile could put you just over a hundred feet off; but a five-degree error starts getting serious at a good 500 feet. With pencil and paper charts, a one-degree error seems quite easy to make.

 

[MrA]

I believe a one-degree bearing error at one nautical mile could put you just over a hundred feet off; but a five-degree error starts getting serious at a good 500 feet. With pencil and paper charts, a one-degree error seems quite easy to make.

on the tests 2 degree error is acceptable, first time I'm doing this and I agree with you the larger the error the farther off course you will be, I can see a lot of factors affecting the results like how thick your lines are, how good your glasses are, how good the light is, if the boat is rocking and of course how many beers you had, if you followed this post from the start, Jackdale asked me the bearing on a line I plotted, I measured it a 359-degrees, Tempest immediately came back with 003-degrees, which was right. I can only hope I will get better with practice, The best I could come up was 001-degree. and I was wondering do sailors even use charts anymore other than emergencies? and would flying and sailing require a similar skill set?

 

[jackdale]

and I was wondering do sailors even use charts anymore other than emergencies? and would flying and sailing require a similar skill set?

I use paper charts to do my planning and plotting. I also know how to use electronic charts (I have three different ones on my Windows tablet). I also know how to use radar fix on paper charts.

I may be an exception.

Being able to paper charts is a skill that should be learned before one starts to use the electronics

 

[MrA]

I use paper charts to do my planning and plotting. I also know how to use electronic charts (I have three different ones on my Windows tablet). I also know how to use radar fix on paper charts.

Explain radar fix?

I may be an exception. Believe I will be also

Being able to paper charts is a skill that should be learned before one starts to use the electronics

this is me now and I enjoy putting pencil to paper

 

[Uricanejack]

Problem solved! Thanks to the crew of Sailnet.....getting ready for ASA 105 written test and for the life of me I can't figure these two problems out? any step by step solution would be greatly appreciated. Your are on a compass course of 300 degrees when you note the monument and the lookout tower on Cuttyhunk Island are in line. Using s Pelorus you determine that the transit formed by the monument and the tower is 130 degrees to starboard. What is the deviation of your compass for this heading?....and the second question is a compass course of 317 degrees and a pelorus transit of 064 degrees to starboard again solving for deviation. I'm too old to be school material, in my youth I was a math wiz but now too many brains cell have retired on me when I need them the most. I just don't understand the process to solve these questions thanks augie

Transits for compass error.

The simplest way to use a transit to figure out the compass error is to steer directly on the transit.
Not always convenient.

The true bearing of the transit can be read by line the parallel rules or plotter. with the two objects in transit. And move to the rose.

Read the variation from rose apply annual change (unless question tells you to ignore it)

True bearing of transit
Variation from chart rose
Magnetic bearing

Deviation.

Compass heading.

This deviation is just for the course in question. To get the deviation on an other course you need a compass you can take an azimuth with or a pylorus.

In this question you are using a pylorus.

Zero is usually right ahead and measure Port, (Red) or Starboard(green) from right ahead.

Steering 300. compass
130 to starboard or right o the heading. Add
430 compass
- 360
070 is the "compass" bearing or azimuth of the transit it if it had been taken by your boats steering compass

Compare this to the transit as taken from the chart.

The second bearing is from a heading of 317 compass
067 to starboard or right of the heading
387 compass
360
027 is the compass bearing or azimuth of the transit if it had been taken with your boats steering compass

This question can only be answered by taking the true transit and variation from the chart or having been told what they are as part of the question.

 

[MrA]

excellent thank you

 

[jackdale]

Leeway as requested.

http://www3.telus.net/jackdale/navlessons/Leeway.pdf