Effect of sulphide on corrosion of copper in seawater

The corrosion of ETP copper in natural seawater and putrid seawater has been studied. The corrosion rates and the sulphide content were monitored at regular intervals. In the absence of oxygen in the putrid media, the presence of sulphide favoured a reduction in the corrosion rate

An analytical study of the sea water slime with reference to bacterial flora

A detailed study of the primary film of slime with reference to the bacterial flora, its quality and quantity, as observed on different material surfaces exposed to sea water is carried out. A correlation has been established between bacteria and slime deposited on different surfaces

Designing of a single pack wash primer for aluminium surfaces in a marine environment

Design aspects and comparative performances of different laboratory formulations of wash primers were studied under laboratory and field conditions with reference to scratch hardness, flexibility, stability, resistance to corrosion and adhesiveness. The different formulations of single pack wash primers tested have shown superiority of the formulation prepared out of “mowital” and that it is comparable in performance to double pack wash primer

Hydrography of the Cochin harbour

The hydrography of the Cochin harbour is studied with reference to air temperature, dissolved oxygen, salinity and pH. The analysis of the data shows unique hydrographical characteristics which are influenced by the monsoon rains. The uniqueness lies mainly in the fluctuations of salinity which registers as low as 0.6‰ during monsoon period to near sea conditions (29.4‰) during the summer period. The dissolved oxygen, temperature and pH also showed fluctuations corresponding to seasons

On the development of a mercury-free ternary aluminium anode for cathodic protection

The development of a new mercury-free ternary aluminum anode (CIFTAL) for cathodic protection of marine structures is described. The new anode demonstrated a current efficiency of 83.5% to 85.4% in a current density range of 5.6 to 166.7 mAdmˉ². The current efficiency remained practically stable at 1.4 mAdmˉ² over a test period of 300 days. The service trials of the anode on steel trawlers and aluminum (Indal M 57 S) sheathed wooden boats have shown satisfactory performance in terms of uniform dissolution, current efficiency and driving voltage. In the wake of legislations restricting the use of anodes containing mercury in an endeavor to control the mercury pollution of the near shore aquatic environment, the new anode (CIFTAL) with its stable current output and high current efficiency merits significance in marine cathodic protection

Selection of materials for marine instruments

The paper describes the selection of materials for the reliable operation of oceanographic instruments. For selecting the material, raft immersion tests were carried out for one year. Results of the tests are presented. Comparisons between metals were discussed

Experimental formulation of an anti fouling paint with tributyl tin oxide as toxic pigment

Results of the experimental formulation of an antifouling paint incorporating TBTO as toxic pigment are presented in this paper. Of the various resins tested, namely, phenolic, cashew nut shell liquid (CNSL), epoxy linseed oil with rosin and limed rosin, the paint composition with limed rosin gave the critical leaching rate of TBTO. Acid alkali test showed dissolution of matrix and visible migration of toxin to the surface. Accelerated corrosion tests had not recorded any signs of corrosion in panels painted with or without barrier coat. Raft exposure studies indicated that the new formulation could resist fouling accumulation on painted panels for 9 months

On the importance of ship-bottom fouling by marine organisms: a techno-economic survey

A high attention has been paid for constant research on the preservation of materials in the marine environment. This includes all phases of design, development, applied engineering and economics which may influence the construction and operation of ships and underwater installations

Studies on arsenical creosote as a wood preservative for marine structures. Part 2. Observation on leaching, corrosion and resistance to borer attack

A detailed study on arsenical creosote with reference to leaching, corrosion and anti-borer properties was carried out. Results showed that aging had very little effect on the preservative which suggested better fixation of the preservative into the wood. Corrosion of mild steel, galvanised iron, aluminium-magnesium alloy (M57S) and copper panels in the preservative was found to be negligible. Normal creosote and low temperature creosote of Regional Research Laboratory, Hyderabad, both fortified with arsenic trioxide resisted borer damage on wooden panels for a period of over five months in the port of Cochin. The performance of low temperature creosote fortified with arsenic was found to be equally satisfactory when compared to normal creosote fortified in the same manner. A loading of 208.6 Kgs/ml³ for Haldu (Adina cordifolia) and 138 Kgs/m³ for Mango (Mangifera indica) in the case of normal creosote and 177 Kgs/m³ for Mango the case of RRL creosote were found to be sufficient for treating the wood

Studies on arsenical creosote as a wood preservative for marine structures. Part 1. Incorporation of arsenic in creosote at various temperatures

A detailed study of the fortification of normal creosote and low temperature creosote with As sub(2) O sub(3) at 40°C, 50°C, 60°C, 70°C, 80°C and 90°C was carried out. When compared to normal creosote, low temperature creosote has been found to combine more easily with As sub(2) O sub(3) when temperature was . raised from 40 to 90°C. The incorporated arsenic values obtained shows that low temperature creosote with high phenolic content, retains considerably more As sub(2) O sub(3) and a maximum of 0.2180% w/w can be incorporated in low temperature creosote at 90°C