Temeljne zakonitosti loksodromske navigacije

In loxodromic navigation two characteristic problems are encountered when calculating the necessary navigational parameters: - a so-called first loxodromic problem in which general loxodromic course and loxodromic distance are determined based on the known absolute point of departure and point of arrival coordinates; - a so-called second loxodromic problem in which the absolute point of arrival coordinates are determined based on the known absolute point of departure coordinates , a known loxodromic course and loxodromic distance run. The current professional and scientific references deal with the modes of solving the above two problems by means of equations deriving from: - a so-called first loxodromic triangle, - a so -called second loxodromic triangle, - a so-called third loxodromic triangle. The paper aims at proving the basic loxodromic triangle regularities (infinitesimal value/final dimensions) on Earth as a sphere of unit radius R1 and their projections onto the Mercator chart. Based upon those regularities, certain theoretical solutions have been offered to calculate all navigational parameters in both loxodromic problems by means of only one loxodromic triangle, whose elements are precisely defined. The proposed calculations eliminate imprecise calculations by means of «geographical mid latitude», all limitations regarding loxodromic distance length and the limitations for angular values of loxodromic course when calculating the parameters in loxodromic navigation. The proposed system presents a contribution to the theory of loxodromic navigation.Pri plovidbi po loksodromi u izračunima potrebnih navigacijskih parametara pojavljuju se dva karakteristična problema: - tzv. prvi loksodromski problem u kojemu se iz poznatih apsolutnih koordinata pozicije polaska i pozicije dolaska određuje opći loksodromski kurs plovidbe i loksodromska udaljenost, - tzv. drugi loksodromski problem u kojemu se iz poznatih apsolutnih koordinata pozicije polaska, poznatoga loksodromskog kursa plovidbe i poznate prijeđene loksodromske udaljenosti određuju apsolutne koordinate pozicije dolaska. U postojećoj stručnoj i znanstvenoj literaturi navedena dva problema rješavaju se s pomoću jednadžba koje su izvedene iz tri loksodromska trokuta: - prvoga loksodromskog trokuta, - drugoga loksodromskog trokuta, - trećega loksodromskog trokuta. U ovom radu dokazane su osnovne zakonitosti između loksodromskih trokuta (infinitezimalne veličine/ konačnih dimenzija) na Zemlji kao kugli jediničnog radijusa R1 i njihovih projekcija na pomorskoj (Mercatorovoj) karti. Na temelju tih zakonitosti prikazana su određena teorijska rješenja kojima se mogu izračunati svi navigacijski parametri za oba loksodromska problema s pomoću samo jednog loksodromskog trokuta sa svim egzaktno definiranim elementima. Predloženim rješenjima eliminiraju se ograničenja duljine loksodromske udaljenosti i ne postoje ograničenja kutne vrijednosti loksodromskoga kursa pri izračunu navigacijskih parametara za plovidbu po loksodromi, što je doprinos unapređenju teorije lokso-dromske navigacije

International Regulations for Preventing Collisions at Sea (COLREGs) amendment proposal

International Regulations for Preventing Collisions at Sea (hereinafter: COLREGs) should apply to all vessels. The term vessel is explained in Rule No. 3, defined as water craft, including non-displacement craft, wing-in-ground craft and seaplanes, used or capable of being used as a means of transportation on water. Regulations do not make any difference between large ships and small boats, regarding all of them as vessels. COLREGs are primarily intended for large vessels, applying also to smaller boats in an appropriate manner

Towards Determining the Length of the Wind Waves of the Adriatic Sea

Valovi, kao morfološki oblik morske površine karakterizirani su visinom, duljinom i periodom, odnosno brzinom. Visinu i period vala moguće je točno odrediti na valomjernim plutačama. Duljinu vala moguće je samo približno odrediti, prema tome i brzinu vala. Najdulji su plimni valovi, kraći su seizmički, još kraći su valovi mrtvog mora, a najkraći su vjetrovni valovi. Vjetrovni valovi su najznačajniji glede sigurnosti pomorskog prometa te će se stoga njihova obilježja razmatrati u ovom radu. U literaturi se susreću matematički izrazi za duljinu vala koji daleko nadilaze vrijednosti koje se susreću na Jadranu. Empirijski izraz = 16,78 H0,71 zadovoljava u pogledu visine vala H i pripadne duljine za Jadran.Waves, as a morphologic form of the sea surface, are characterised by their height, length and period, or speed. The height and period of the wave can be measured with a high degree of accuracy by means of oceanographic measuring buoys. The length of the wave can be approximately derived, as well as the speed. The longest are the tide waves, shorter are the seismically waves, even shorter are the waves of the swell, while the windy waves are the shortest ones. The windy waves are the most important from the safety point of view and their characteristics will be analyzed in this paper. The technical literature is full of mathematical equations for the length of waves which exceed extensively the parameters of the Adriatic Sea waves. The empiric formula = 16,78 H0,71 correctly determines the lenght of the Adriatis Sea wave H and its corresponding length