Biofouling Characterization and its Effect on Resistance of Surface Ship

Manufacture of coatings to tackle the biofouling menace has been of prime concern for the shipping industry since industrial revolution. Even though many types of coatings exist in the market, they have not been able to wipe out the problem of biofouling completely. The proposed approach which combines both the resistance due to biofouling on ships, as well as biofouling characterization, will surely serve as a critical input for the manufacture of efficient anti-fouling coatings. Resistance simulations have been carried out for a tanker ship by Maxsurf® wherein the hull fouling effect has been accounted for by modified ITTC 1978 empirical formula considering roughness. Different draft conditions were relied upon to find out the resistance at various Froude numbers. The fouling growth conditions considered are small and medium calcareous fouling. The simulated results also have been validated by towing tank experiments, for no-foul condition, for speeds varying from 0.3 to 1.1 m/s and different drafts. The additional power requirement was determined for various loading conditions and speed ranges.

Survey of Fouling Organisms at Songkhla Port in Thailand

The fouling organisms at Songkhla Port were investigated from November 2011 to December 2012. Samples were collected using PVC panels (10 cm x 20 cm) submerged for one-month and three-month periods. Analysis of fouling panels was carried out using PhotoGrid software. In addition to slime and silt, three types of fouling organisms, namely encrusting bryozoa, barnacles and calcareous polychaetes, were observed on the submerged PVC panels. Calcareous polychaetes and molluscs were the most diverse groups (ten species) on panels that were submerged for one-month and three-month periods. Barnacles (Balanus spp.) were most abundant on panels submerged for three-month periods, while calcareous polychaetes dominated one-month panels. The dominant species of mollusc was the mussel Brachidontes sp. The major polychaetes identified were Ficopomatus macrodon, F. enigmaticus and Hydroides norvegicus. A highlight of this study was the first record of the Caribbean tubeworm Hydroides sanctaecrucis in Thailand, which has previously invaded and established in Australian waters through hull fouling.

First report of the invasive macroalga Acrothamnion preissii (Rhodophyta, Ceramiales) in the Atlantic Ocean

Acrothamnion preissiiis an invasive species in the Mediterranean Sea, and is listed among the 100 worst non-indigenous species. In July and August 2009, this non-native red macroalga was found for the first time in the Azores (on Santa Maria), and this represents the first record of this species in the Atlantic. Here, we describe the establishment of this invasive species in the Atlantic. In recent surveys,A. preissiidisplayed an invasive behaviour. As suggested for the Mediterranean Sea, hull fouling is the most likely vector for its introduction into the Azores.