Treatment behaviour of fresh and inservice catamaran logs
V Kuppusamy, M V Rao, M Balaji, K S Rao
Catamaran is a conventional fishing craft fabricated by lashing 4 - 6 shaped logs of soft timber together. Over 73,000 of these craft fabricated out of 165,000 m3 of wood are in use along the vast east coast of India. Each craft lasts for 5-7 years. Over 15,000 m3 of timber is required annually for repairs and replacements of the craft. Such huge demand exerts enormous pressure on the resources. It is apt, therefore, to extend the practice of wood preservation to the catamaran sector and conserve the precious raw material. In order to achieve this objective, our Institute took up technology demonstrations way back in 1968. However, because of illiteracy and socio-economic constraints of the traditional fishermen, the efforts did not catch up well. Under these circumstances, as a renewed measure of propagation, treatment of 3 each of fresh as well as inservice catamarans was taken up some time ago. The results of pressure impregnation of these six catamarans made of Albizia falcataria timber with copper-chrome- arsenic (CCA) preservative were analyzed to understand the preservative absorption of the constituent logs. The study revealed that there was no significant variation in the total quantity of chemical absorbed among the fresh as well as inservice catamarans that served for three different periods prior to treatment . However, significant difference was noticed between all the fresh catamarans clubbed as one group and the inservice craft as another group. The CCA absorption ranged from 13.52 to 15.30 kg.m-3 averaging at 14.60 kg.m-3 in the fresh craft and 18.65 to 22.10 kg.m-3 averaging at 20.42 kg.m-3 in the inservice catamarans. Also, each constituent log of the six catamarans differed in its chemical content from the other. The analysis proved that it is possible to treat the inservice catamarans and achieve good preservative retentions.