نشریه مهندسی شناورهای تندرو
پیاپی 53 (پاییز و زمستان 1397)

Today, nanotechnology is used as one of the newest and most practical methods to reduce frictional drag force, increase speed and life span of vessels. The coatings used in the floats should be resistant to seawater, salts, corrosive agents, water penetration and algae growth. The first and most important application of coatings on the vessels is to use them to reduce surface corrosion. Corrosion usually begins at the surface of the material and permanently reduces the life span of the materials used. Nanoparticle materials exhibit unique physical and chemical properties, which can improve the corrosion resistance of these materials. Nano-colors are one of these types of coatings used in marine industries. The use of nanotechnology in the color industry prevents clogging of pockets to float and prolongs the life of floats. Another way to improve the surface properties of marine vessels and increase their lifespan is to use nano-composite coatings. The most important application of the coatings on the vessels is to increase their speed due to the reduced floating resistance against frictional drag force. The friction drag force directly measures the amount of force needed to move the body. An effective new method for reducing drag forces is the use of nano coatings, which reduces the strength of the resistor and the amount of sediment formed on the floating body.

One of the many types of vessels that have been exploring, designing, and exploiting for many years are Hydrofouil vessels .Hydrofoil vessels, despite to have The Irrefutable Benefits, because of their special structure, which, when separated from the water surface, are mounted only on two structures called hydrofoil, in different moments, such as when separating from the water surface, forming a cavitation, wave Or change the speed of falling into the water, so eliminating or discount this disadvantage will make the Practical and Advantages bold this is type of boat And can be used to build and operate Hydrofoil vessels and create a real place for them among other types of vessels.. In this paper, with the help of the experience gained in the design and construction of a one-meter hydrofoil boat and available information, longitudinal instability and methods for reduce it in this type of vessel are investigated in order to be a step in their better design.

Awareness of marine parameters is one of the main requirements for maritime missions, and in particular, sea currents are of particular importance. In the Persian Gulf which is considered a shallow water zone, this is among the priorities of environmental recognition. The origin of Gulf currents is mainly density, wind and tide. In the meantime, tide is of particular importance due to the prevailing factor in the creation of momentary flows of numerical hydrodynamic models, hydrography, sediment transport, and others. Since in many navigation and maritime affairs, port management and coastal engineering activities, marine currents are especially important for short-term tidal currents. This paper explores the tidal and sea currents In the Persian Gulf. The results indicate that the main factor in the tidal currents of the Persian Gulf is the moon. The tide type also follows a different pattern in different parts of the Persian Gulf, which is usually half a day in the northern half, but daily in the southern half.

ABSTRACT The purpose of this paper is to explore the feasibility of solar energy use in cooling systems and air conditioning in vessels. The importance of solar energy has increased in recent decades. Solar energy is known today as a widely used tool for optimization and development of cooling, heating and air conditioning processes. Solar cells absorb solar energy and convert it into electricity. due to the expensive of semiconductor materials, these cells and their low efficiency (5 to 18 percent)of the sea industry are less interested. Compatibility with the environment, renewable and being cheap is from the benefits of solar energy. The use of solar energy is not only expanding in the Majority World, but in the future as one of the factors of development. due to the effect of climate change and global warming, the need for ventilation and refrigeration is increasing, one of the important applications of solar energy use in cooling [ 1 ].there are two direct methods of photovoltaic (PV)and indirect (solar thermal)power in generating electricity. In photovoltaic , solar radiation are directly converted into electricity. Power produced by photovoltaic systems can be used for ventilation and refrigeration in vessels. This paper investigates the feasibility of using solar energy for ventilation and cooling of the command of a vessels chamber of thunder in the south of the country [2].

The design of ship maneuvers in the early stages of ship design and operation is of great importance. Having a precise model of vessel maneuvers along with the coefficients in the maneuvering equations of ships, is essential for research on maneuverability of vessels, the design of a ship motion control system, and the development of ship maneuvers simulators. Over the past few years, there have been various models of maneuvering ships that can explain ship maneuvers with an appropriate approximation. The design of ship maneuvers in the early stages of ship design and operation is of great importance. Having a precise model of vessel maneuvers along with the coefficients in the maneuvering equations of ships, is essential for research on maneuverability of vessels, the design of a ship motion control system, and the development of ship maneuvers simulators. Over the past few years, there have been various models of maneuvering ships that can explain ship maneuvers with an appropriate approximation.

Now, different advanced radar technologies are used in military missions. LPI radars are desired technologies because of their stealth properties. It is obvious that having informations about the enemy’s radar capabilities in marine missions of navy forces to guarantee to be stealth completely, is effective on the success of high speed crafts navy missions. Because, it is necessary to be invisible completely from enemy’s radars when closing to our predetermined targets to do some missions. For this, we need to detect the present LPI radars in sea more confidently to be sure that are we invisible from enemy equipments or not. Therefore, in this paper we present a multi-algorithm method detection method of determined LPI-FMCW radar for improving the capability of high speed crafts in navy missions. The computational simulations for a pilot LPI radar proves the suitability of our proposed algorithm, which has merits more than similar previous related algorithms.