- Parallels: Circles parallel to the equator, ranging from 0° to 90° N or S. Only the equator is a great circle.
- Meridians: half-circles converging at the poles, ranging from 0° to 180° E or W. Each pair of opposing meridians forms a great circle.
- Prime meridian: 0° or the Greenwich meridian which – together with the date line meridian – divides the Western and Eastern hemispheres.
- Great circle: The intersection of a sphere and a plane that passes through the sphere’s centre.
- Small circle: The intersection of a sphere and a plane that doesn’t pass though the sphere’s centre.
- Time zones: By convention 24 zones, each 15° longitude wide. Hence, noon at Greenwich gives midnight at 180° E.
- GMT, UTC, Zulu: The outdated accronym GMT (Greenwich Mean Time) is roughly the same as UTC or Zulu, and is also the local time at Greenwich when daylight saving isn’t used. Note that UTC is an atomic time scale which only approximates GMT, so best to use the modern term “UTC”. Antonym: Local time elsewhere. For example, local time in Athens = UTC + 2.
- Date line: The 180° meridian which extends from or is opposite to the prime meridian. Here, not only the hour changes when crossing the meridian, but also the date.
- Latitude: Position property defined by the number of degrees north or south of the equator, varies from 0° to 90°.
- Longitude: Position property defined by the number of degrees east or west of the prime meridian, varies from 0° to 180°.
Glossary Nautical Charts
April 25th, 2010 by admin 1 comment »
POSITIONS
April 25th, 2010 by admin No comments »Longitude and latitude
The earth can be regarded as a spherical object, and since we’re dealing with a 3-dimensional shape we need coordinates of a different form than the usual x- and y-axes. Though adding an extra z-axes would make sense for submarines, we will most likely be found on the surface of this sphere while using another system of coordinates, 
that covers our planet with imaginary lines called meridians and parallels, see figure 1. All these lines together provide the grid which enables us to describe any position in longitudes and latitudes
The obvious place to divide the Northern and Southern Hemispheres was the equator. But the division of the Eastern and Western hemispheres was the source of much political turmoil. Greenwich (Great Britain) won, placing for example The Netherlands in the Eastern and Ireland in the Western Hemisphere.
It takes the earth 24 hours for a full rotation of 360°. Thus, every hour we rotate 15° longitude, see figure 2.
When it is 12:00 UTC (international standard time) – anywhere in the world – it is 12:00 Local Time in Greenwich and 24:00 Local Time at the other side of the planet: 180° E or 180° W: the date line. Crossing this special meridian changes not only the hour but also the date.
Marine Compass
April 25th, 2010 by admin No comments »In China compasses have been in use since the Han dynasty (2nd century BCE to 2nd century CE) when they were referred to as “south-pointers”. However at first these magnets were only used for geomancy much like in the art of Feng Shui.
Eventually, during the Sung dynasty (1000 CE) many trading ships were then able to sail as far as Saudi Arabia using compasses for marine navigation. Between 1405 and 1433, Emperor Chu Ti’s Treasure Fleet of the Dragon Throne ruled the entire South Pacific and the Indian Ocean, a territory that ranges from Korea and Japan to the Eastern coast of Africa.
At this time Western mariners were still rather ignorant of the navigational use of the magnet. Petrus Perigrinus van Maricourt wrote a first treatise on the magnet itself: “De Magnete” (1269). And though its nautical use was already mentioned in 1187 by the English monk Alexander Neckham, the use onboard only came about around the 13th and 14th century in the Mediterranean Sea.
Much later, in 1545, Pedro de Medina (Sevilla 1493-1567) wrote the Spanish standard work “Arte de Navegar” on marine compass navigation. This masterpiece was first translated in Dutch (1580) and was -O Irony- used by Jacob van Heemskerk when the Dutch destroyed the Spanish fleet near Gibraltar in 1607. The drawback was of course Van Heemskerk’s own death during this victory.
Magnetic Variation
In the fin-de-siècle of the sixteenth century mariners believed that the magnetic north pole coincided with the geographic north pole. Any suggestion otherwise had been denied by Pedro de Medina. 
Magnetic observations made by explorers in subsequent decades showed however that these suggestions were true. But it took until the early nineteenth century, to pinpoint the magnetic north pole somewhere in Arctic Canada (78° N , 104° W). From then on the angle between the true North and the Magnetic North could be precisely corrected for. This correction angle is called magnetic variation or declination.
It is believed that the Earth’s magnetic field is produced by electrical currents that originate in the hot, liquid, outer core of the rotating Earth. The flow of electric currents in this core is continually changing, so the magnetic field produced by those currents also changes. This means that at the surface of the Earth, both the strength and direction of the magnetic field will vary over the years. This gradual change is called the secular variation of the magnetic field. Therefore, variation changes not only with the location of a vessel on the earth but also varies in time.
Merencanakan Pelayaran
April 24th, 2010 by admin No comments »
Pada abad ke-21, bila anda berlayar anda harus mengambil keprutusan dari dunia ( modern dan kuno ) yang mengatakan bahwa anda bisa dapat menentukan posisi kapal Anda : dengan peta, kompas dan pensil, namun anda harus cukup akrab dengan peralatan elektronik dan lain-lain yang dibuat, ( untuk mempermudah hidup anda).
Kuno, paling mahal dan paling tidak terlalu efektif adalah alat navigasi radio pencari arah – RDF. Hal ini tidaklah terlalu akurat dan harga lebih mahal dibanding sistem loran, yang lebih tepat dan menyajikan informasi dalam suatu bentuk visual, yang mungkin lebih baik digunakan. Yang paling penting sistem navigasi radio untuk non-profesional saat ini adalah Loran-C dan GPS (Global Positioning System). Sistem pantai Loran berbasis gelombang radio transmisi, sedangkan GPS menerima sinyal dari satelit di orbit bumi. GPS yang paling akurat, paling mahal, dan paling rentan terhadap atmosfer.
Peraturan Internasional Pencegahan Tubrukan di Laut(P2TL)
April 24th, 2010 by admin 1 comment »BAGIAN A – UMUM
PEMBERLAKUAN
Aturan 1
a. Aturan-aturan ini berlaku bagi semua kapal di laut kepas dan di semua perairan yang berhubungan dengan laut yang dapat dilayari oleh kapal-kapal laut.
b. Tidak ada suatu apapun dalam aturan-aturan ini yang menghalangi berlakunya peraturan-peraturan khusus ysng dibuat oleh penguasa yang berwenang, untuk alur pelayaran, pelabuhan, sungai, danau atau perairan pedalaman yang berhubungan dengan laut dan dapat dilayari oleh kapal laut. Aturan-aturan khusus demikian itu harus semirip mungkin dengan aturan-aturan ini.
c. Tidak ada suatu apapun dalam aturan-aturan ini yang akan menhalangi berlakunya aturan-aturan khusus yang manapun yang dibuat oleh pemerintah Negara manapun berkenaan dengan tambahan kedudukan atau lampu-lampu isyarat, sosok-sosok benda atau isyarat-isyarat suling untuk kapal-kapal perang dan kapal-kapal yang berlayar dalam iring-iringan atau lampu-lampu Isyarat, atau sosok-sosok benda untuk kapal-kapal ikan yang sedang menangkap ikan dalam satuan armada.
Pertanggungan Jawab
Aturan 2
» Read more: Peraturan Internasional Pencegahan Tubrukan di Laut(P2TL)
MELIHAT LEBIH JAUH KAPAL TNI AL
April 18th, 2010 by admin No comments »Ini kapal KRI Tanjung Dalpelle 972, merupakan jenis kapal rumah sakit yang dipunyai oleh TNI AL
PROSES PEMBUATAN KAPAL CARGO
April 14th, 2010 by admin No comments »1.Bahan pelat baja disiapkan
2.pelat baja tersebut dicat dasar agar tidak terjadi korosi.
3.lalu dikumpulkan dan diberi pola untuk nantinya dipotong sesuai dengan ukuran yang telah dibuat oleh desainer nya
4.setelah selesai di potong,,maka tahap selanjutnya menyambung dengan las
5.semuanya disambung per kompartemen atau per bagiannya, karenabesar. setelah bagian kecilnya selesai dirakit,lalu bagian tersebut disatukan di tempat yang dinamakan DOK
6.setelah smua bagian kapal tersebut terpasang,, maka kapal tersebut diturunkan ke air dan di tambat di dermaga.
pengerjaan di dermaga tersebut adalah untuk memasang mesin kapal, sistem kelistrikan, generator,,navigasi,,dan pengecatan kapal
7.setelah semua sistem diuji dan telah mampu bekerja maka telah selesai pembuatan kapal tersebut
PLIMSOLL MARK
April 2nd, 2010 by admin No comments »Garis deck
ditampilkan di sini hanya untuk ilustrasi. Biasanya jarak antara garis geladak dan tanda Plimsoll lebih besar dari yang ditampilkan di sini. Jarak antara garis geladak dan tanda dimana kapal tersebut dimuat adalah Freeboard tersebut. Tanda diperlukan untuk secara permanen tetap ke bagian tengah kapal kapal di kedua sisi lambung dan dicat dengan warna yang kontras dengan warna lambung.
LTF – Lumber, Tropis Segar – Ini adalah konsep dimana kapal dapat membawa beban ketika kayu di zona Segar Tropis ditunjuk.
LF – Kayu, segar – ini adalah draft kapal yang dapat membawa beban ketika kayu di zona ditunjuk segar.
LT – Lumber, Tropis – Ini adalah draft kapal yang dapat membawa beban ketika kayu di zona tropis yang ditunjuk.
WATERLINE
April 2nd, 2010 by admin No comments »The national Load Line or Plimsoll Line (waterline),
positioned amidships, indicates the legal limit to which a ship may be loaded for specific water types and temperatures. To an observer on the ship the water appears to rise or fall against the hull. Temperature affects the level because warm water provides less buoyancy, being less dense than cold water. The salinity of the water also affects the level, fresh water being less dense than salty seawater. For vessels with displacement hulls, the hull speed is determined by, amongst other things, the waterline length. In a sailing boat, the length of the waterline can change significantly as the boat heels, and can dynamically affect the speed of the boat.
In aircraft design, the term waterline refer to the vertical location of items on the aircraft. This is the (normally) “Z” axis of an XYZ coordinate system, the other two axes being the Fuselage Station (X) and Buttock Line (Y) The purpose of a ‘load line’ is to ensure that a ship has sufficientfreeboard and thus sufficient reserve buoyancy. The freeboard of commercial vessels is measured between the lowest point of the uppermost continuous deck at side and the waterline and this must not be less than the freeboard marked on the Load Line Certificate issued to that ship. All commercial ships, other than in exceptional circumstances,[1] have a load line symbol painted amidships on each side of the ship. This symbol must also be permanently marked, so that if the paint wears off it remains visible.
Ilmu Perkapalan Dan Teknologi Kelautan
April 2nd, 2010 by admin No comments »Teknologi kelautan
terutama dalam bidang perkapalan memiliki peranan penting dalam memberikan pemahaman awal tentang dunia perkapalan. Ukuran geometri kapal dapat sebagai pijakan awal dalam memahami ilmu perkapalan terutama dalam perancangan rencana garis, diantaranya :
AP After Perpendicular/garis tegak buritan adalah garis tegak yang terletak pada sisi belakang sterpost atau bila tidak ada sternpost, FP terletak pada sumbu poros kemudi.
FP Forward Perpendicular/garis tegak haluan adalah garis tegak vertikal yang melalui interseksi antara garis air muat/garis air perencanaan /DWL dan sisi dalam linggi haluan.
LBP Panjang antara garis tegak / Length between perpendicular adalah jarak horizontal antara AP dan FP.
LWL Panjang garis air/ Length of water lines adalah jarak horisontal antara FP dan interseksi antara sisi dalam linggi buritan dan garis air muat/garis air perencanaan/DWL.
