The Northeastern Sea Chart is in the Temple of the Ocean King. To reach it you need to find a room with three variously shaped crystal pedestals in a row. Place the crystals on them in the order square, circle, triangle to proceed.
If you already have the sea chart, than I think you go to the SE quadrant and sail N.
you go to the northeaster sea. Goron island is your first stop when you get there.
Yes,you can find items on mercay island for phantom hourglass,in the temple of the ocean king.You can find the the southwestern sea chart (no requirements),the phantom hourglass,the northwestern sea chart (after you beat the temple of fire for both),the southeastern sea chart and the northeastern sea chart (after you beat the ghost ship for both).
The Red Sea
If you are refering to the three pure metals used to make the phantom sword, then you will need to go down into the Temple of the Ocean King and search for the last two sea charts. The southeastern is easy to find, but the northeastern is a little tricky to find. You can refer to other questions on how to find the northeastern sea chart.
THE LAST SEA CHART IS IN THE OCEANS KING TEMPLE. (you only get the sea chart the 5th time you are sent there)
You get the last sea chart in the Temple of the Ocean King, B12. You get the last sea chart in the Temple of the Ocean King, B12.
Northeastern Africa, on the Red Sea and Mediterranean Sea.
The Red Sea lies on Africa's northeastern border. It separates northeastern Africa from the Arabian Peninsula and is linked to the Indian Ocean via the Bab el Mandeb strait in the south.
The 4rth sea chart
They are all in the Temple of the ocean king 1st sea chart is on the 1st floor 2nd sea chart is on the 3rd floor 3rd sea chart is on the 9th floor 4th sea chart is on the 13th floor Hope this helped :D Claudia
You can't find the Old Sea Chart in FireRed.