Day Skipper theory - Charts the magic of the maps

Рет қаралды 29,695

Learn 2Sail

2 жыл бұрын

Introduction into how to use a nautical chart for navigation. Latitude and longitude explained.

Пікірлер: 23

@newfie8 9 ай бұрын

Great Job. Sometimes people don’t realize how important people like you are!

@waldek32 Ай бұрын

finally clear english and visible explanation . greetings from Poland

@bluecap5434 2 жыл бұрын

thanks for the very useful information you kindly provide. looking forward to hearing soon.

@macgyver6115 Жыл бұрын

Thank you for your time, to make these excellent videos

@faisalsaaid634 Жыл бұрын

Great Explanation ., Thank you From Yemen

@harbourdogNL 2 жыл бұрын

Thank you.

@LexLuthor1234 9 ай бұрын

Grazie! :)

@B-Heff-M3 5 ай бұрын

Great little video 👌

@Learn2Sail 5 ай бұрын

Glad you enjoyed. Cheers

@robertprecious2614 Жыл бұрын

I am about to do my day skipper course and what I would find helpful is a priority list of what calcs need to be done in the correct order so as not to forget anything?

@Learn2Sail Жыл бұрын

Each subject will be different, so best learn as you go along

@eddsummat2191 Ай бұрын

So in reading charts is the opposite way to reading an OS map (along the corridore and up the stairs) ie would be long the lat no for a grid reference

@Learn2Sail Ай бұрын

Yup. I guess it is. Latitude first, then longitude. On the bottom or horizontal scale

@brooklynnunya1179 Жыл бұрын

Cool

@jimmybrokos4610 2 жыл бұрын

👍🏼👍🏼👍🏼

@lukasvandewiel860 Жыл бұрын

Perhaps add that longitudinal minutes of arc are nautical miles only at the equator, and that they get smaller as you move closer to the poles, because the circles around the planet become smaller. (Genuine question: Do we take into account that the Earth is better approximated by an ellipsoid than by a perfect sphere, because of its rotation, or is that effect too insignificant?)

@Learn2Sail Жыл бұрын

Thanks for the comment, but the video is geared at those just starting out in learning charts, too much information to start with would swamp them. These things get mentioned in the classroom. Thanks for your input.

@lukasvandewiel860 Жыл бұрын

@@Learn2Sail From your youtube marketing there is a reasonable chance that we will see each next summer during a Competent Crew course. ;-) I will prepare by studying the navigation theory by the light of the Christmas tree. :-)

@bigglyguy8429 Жыл бұрын

I can understand how the longitude lines will change across the curvature of the Earth, but I thought the parallels were called that because they are equally spaced?

@lukasvandewiel860 Жыл бұрын

@@bigglyguy8429 The planes through parallels are all indeed parallel as you say. If you stand on a parallel, and draw and imaginary line from your feet to the center of the earth, the angle that line makes with the equatorial plane is the value of the parallel. If the earth were a perfect sphere, the arc distance from parallel to parallel would be the same from equator to pole. However, the centrifugal force due to rotation of the earth turns our planet into an ellipsoid. If you are standing at sea level at the equator, you are standing about 6378 km from the center of the earth. At the poles that is just 6357 km. 21 km difference. This causes the parallels near the equator to be further apart than at the poles. A degree latitude at the equator is very close to 2 * pi * 6378 / 360 = 111.317 km and a degree latitude at the poles is very close to 2 * pi * 6357 / 360 = 110.951 km. Almost 400 meter difference. Might be small enough to ignore on the vast ocean, or it might not be.

@bigglyguy8429 Жыл бұрын

@@lukasvandewiel860 Thanks for that. It's interesting to know. Is this accounted for on charts?